Astronomy Ch. 7 Practice Quiz, Astronomy Chapter 7, ISP 205 MA Exam 2, astronomy test 2, Astronomy 101 Study Guide

Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true?

All the planets orbit counterclockwise around the Sun.

Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true?

All the planets orbit counterclockwise around the Sun.

cosmos

An alternative name for the universe.

less than the thickness of a human hair held at arm's length

An angle of 1 arcsecond is _________.

Interferometry uses two or more telescopes to achieve ...

An angular resolution equivalent to that of a much larger telescope.

small solar system body

An asteroid, comet, or other object that orbits a star but is too small to qualify as a planet or dwarf planet.

According to our theory of solar system formation, which law best explains why the central regions of the solar nebula got hotter as the nebula shrank in size?

The law of conservation of energy

Which of the following statements about the recently-discovered object Eris is not true?

It is thought to be the first example of a new class of object.

What is the purpose of adaptive optics?

It reduces blurring caused by atmospheric turbulence for telescopes on the ground.

Why has NASA sent recent orbiters to Mars on trajectories that required them to skim through Mars's atmosphere ("aerobraking") before settling into their final orbits?

It saved money because the spacecraft used atmospheric drag to slow down rather than needing to carry enough fuel to slow by firing rocket engines.

Betelgeuse is the bright red star representing the left shoulder of the constellation Orion. All the following statements about Betelgeuse are true. Which one can you infer from its red color?

Its surface is cooler than the surface of the Sun.

Betelgeuse is the bright red star representing the left shoulder of the constellation Orion. All the following statements about Betelgeuse are true. Which one can you infer from its red color? It is much more massive than the Sun. Its surface is cooler than the surface of the Sun. It is much brighter than the Sun. It is moving away from us.

Its surface is cooler than the surface of the Sun. Red light has lower energy than yellow or white light, so the red color of Betelgeuse tells us that its peak thermal radiation comes at lower energy than the peak thermal radiation of the yellow/white Sun. A lower energy of peak radiation means a lower temperature.

Pluto is different from the outer planets in all of the following ways except which one?

Its surface temperature is very cold.

b

Jupiter nudges the asteroids through the influence of a. tidal forces. b. orbital resonances. c. magnetic fields.

dark energy

Name sometimes given to energy that could be causing the expansion of the universe to accelerate. see cosmological constant.

Radio telescopes are large in part to improve their angular resolution, which is poor because of the long wavelengths at which they are used to observe the skies

True

The lens in your eye forms an upside-down image of the world.

True

Consider an atom of carbon in which the nucleus contains 6 protons and 7 neutrons. What is its atomic number and atomic mass number?

atomic number = 6; atomic mass number = 13

When we say that jovian planets contain significant amounts of hydrogen compounds, we mean all the following chemicals except ______.

carbon dioxide

When we say that jovian planets contain significant amounts of hydrogen compounds, we mean all the following chemicals except

carbon dioxide.

Most of the Sun's ultraviolet light is emitted from the narrow layer called the ______ where temperature increases with altitude.

chromosphere

A typical galaxy is a _________.

collection of a few hundred million to a trillion or more stars, bound together by gravity

The ___________ of the Hubble Space Telescope is better for shorter (bluer) wavelengths of light than for longer (redder) wavelengths of light

angular resolution

dwarf planet

orbits a star, is large enough for its own gravity to make it round

When considering light as made up of individual "pieces," each characterized by a particular amount of energy, the pieces are called _________.

photons

Which of these layers of the Sun is coolest? core radiation zone photosphere

photosphere

nearly all the visible light we see from the Sun is emitted from the ______

photosphere

Rank the layers of the Sun's atmosphere based on their density, from highest to lowest. Corona chromosphere photosphere

photosphere chromosphere corona As your answer correctly indicates, the density of the Sun's atmosphere decreases with altitude above the photosphere.

Which planet listed below has the most extreme seasons?

uranus

A television advertisement claiming that a product is light-years ahead of its time does not make sense because _________.

it uses "light-years" to talk about time, but a light-year is a unit of distance

Which of the following is farthest from the Sun?

a comet in the Oort cloud

The age of our solar system is about:

one-third of the age of the universe.

nuclear fusion

The process in which two (or more) smaller nuclei slam together and make one larger nucleus.

Which forms of light are lower in energy and frequency than the light that our eyes can see?

infrared and radio

Based on observations of the universal expansion, the age of the universe is about _________.

14 billion years

A 10-meter telescope has a larger ___________ than a 4-meter telescope.

light-collecting area

galaxy cluster

see cluster of galaxies.

Which of the following statements about the object called Eris is not true?

It is thought to be the first example of a new class of object.

Which of the following statements is not an observed pattern of motion in our solar system?

Most planets orbit at the same speed.

axis tilt

(of a planet in our solar system) The amount by which a planet's axis is tilted with respect to a line perpendicular to the ecliptic plane.

expansion

(of the universe) The idea that the space between galaxies or clusters of galaxies is growing with time.

solar system

(or star system) A star (sometimes more than one star) and all the objects that orbit it.

Suppose you have a 100-watt light bulb that you leave turned on for one minute. How much energy does it use?

6,000 joules

If the 14 billion year history of the universe were compressed to one year, and "now" is exactly midnight December 31, approximately how long ago were your grandparents born?

0.15 second ago

Suppose a photon has a frequency of 300 million hertz (300 megahertz). What is its wavelength?

1 meter

Based on the frequency with which we see comets from Earth, astronomers estimate the total number of comets in the solar system to be

1 trillion.

1. The ______ of the Hubble Space Telescope is better for shorter (bluer) wavelengths of light than for longer (redder) wavelengths of light. 2.The large research observatories on Mauna Kea use giant ______ 3._____ separate the various colors of light, allowing astronomers to determine stellar composition and many other stellar properties 4.__________ separate the various colors of light, allowing astronomers to determine stellar composition and many other stellar properties 5. The Chandra X-ray observatory focuses X rays with ____ mirrors. 6. A 10-meter telescope has a larger ______ 7.Galileo's telescope designs using lenses were examples of ____

1. Angular Resolution 2. Reflecting Telescopes 3. Spectrographs 4. Interferometry 5. Grazing Incidence 6. Light-collecting area 7. Refracting Telescopes

The value of radio and infrared astronomy is partly based on the fact that light at these wavelengths can travel through cosmic clouds of gas and dust without being absorbed. That means astronomers can observe phenomena in our Galaxy and in other galaxies that otherwise would be hidden from view at optical and shorter wavelengths. Radio emission at centimeter-to-meter wavelengths can be effectively observed from the ground. What are other unique characteristics of radio astronomy within this wavelength range?

1. Areas 2. Baselines 3. Interferometers 4. Storms

How much greater is the light-collecting area of one of the 10-meter Keck telescopes than that of the 5-meter Hale telescope?

4

Suppose astronomers built a 20-meter telescope. How much greater would its light-collecting area be than that of the 10-meter Keck telescope?

4

An atom which has 4 protons and 6 neutrons will be electrically neutral if it contains ______.

4 electrons

According to modern science, approximately how old is the Sun? 11,000 years 400 million years 4.5 billion years 25 million years

4.5 billion years

group (of galaxies)

A few to a few dozen galaxies bound together by gravity. see also cluster of galaxies.

In what part of the electromagnetic spectrum do the biggest telescopes on Earth operate? A) radio B) infrared C) visible D) ultraviolet E) X-ray

A) radio

cluster of galaxies

A collection of a few dozen or more galaxies bound together by gravity; smaller collections of galaxies are simply called groups.

cluster of galaxies (or group of galaxies)

A collection of galaxies bound together by gravity. Small collections (up to a few dozen galaxies) are generally called groups, while larger collections are called clusters.

The value of X-ray and gamma-ray astronomy is based on the fact that some of the most energetic sources in the cosmos radiate at these wavelengths. Magnetic storms in stellar atmospheres (including storms on the Sun), exploding stars and their nebular remnants, the regions surrounding neutron stars and black holes, and the innermost regions associated with active galactic nuclei characterize the highest energy, shortest wavelength regime. What would you need to obtain a successful X-ray image of a high-energy source?

A cosmic source of high temperature A telescope designed and built to be launched into space

supercluster

A gigantic region of space in which many groups and clusters of galaxies are packed more closely together than elsewhere in the universe.

galaxy

A great island of stars in space, all held together by gravity and orbiting a common center, with a total mass equivalent to millions, billions, or even trillions of stars.

galaxy

A great island of stars in space, containing millions, billions, or even trillions of stars, all held together by gravity and orbiting a common center.

Which of the following statements about thermal radiation is always true?

A hot object emits more radiation per unit surface area than a cool object.

Which of the following statements about thermal radiation is always true? A hot object produces more total infrared emission than a cooler object. All the light emitted by hot object has higher energy than the light emitted by a cooler object. A hot object emits more radiation per unit surface area than a cool object. A cold object produces more total infrared and radio emission per unit surface area than a hot object.

A hot object emits more radiation per unit surface area than a cool object. This is part of the first law of thermal radiation (the Stefan-Boltzmann law)

In what wavelength range was interferometry first routinely used? A) radio B) infrared C) optical D) ultraviolet E) X-ray

A) radio

star

A large, glowing ball of gas that generates energy through nuclear fusion in its core. The term star is sometimes applied to objects that are in the process of becoming true stars (e.g., protostars) and to the remains of stars that have died (e.g., neutron stars).

star

A large, glowing ball of gas that generates heat and light through nuclear fusion in its core. Our Sun is a star.

planet

A moderately large object that orbits a star and shines primarily by reflecting light from its star. According to the current definition, an object can be considered a planet only if it orbits a star, is large enough for its own gravity to make it round, and has cleared most other objects from its orbital path.

planet

A moderately large object that orbits a star and shines primarily by reflecting light from its star. More precisely, according to a definition approved in 2006, a planet is an object that (1) orbits a star (but is itself neither a star nor a moon); (2) is massive enough for its own gravity to give it a nearly round shape; and (3) has cleared the neighborhood around its orbit. Objects that meet the first two criteria but not the third, including Ceres, Pluto, and Eris, are designated dwarf planets.

In order for an atom to absorb a photon (a particle of light), the photon must have energy matching the difference in energy between energy levels in the atom. the atom must have lost all of its electrons. the photon must have enough energy to remove an electron from the atom. A or C B or C

A or C the photon must have energy matching the difference in energy between energy levels in the atom. the photon must have enough energy to remove an electron from the atom.

Which of the following statements best describes the difference between a refracting telescope and a reflecting telescope?

A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light

Which of the following statements best describes the difference between a refracting telescope and a reflecting telescope?

A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light.

What is the Kuiper belt?

A region of the solar system beginning just beyond the orbit of Neptune that contains many icy comets.

comet

A relatively small and ice-rich object that orbits a star.

asteroid

A relatively small and rocky object that orbits a star.

asteroid

A relatively small and rocky object that orbits a star; asteroids are officially considered part of a category known as "small solar system bodies."

comet

A relatively small, icy object that orbits a star. Like asteroids, comets are officially considered part of a category known as "small solar system bodies."

b

A rocky leftover planetesimal orbiting the Sun is a. a meteorite. b. an asteroid. c. a meteor. d. a comet. e. possibly any of the above

star system

A star (sometimes more than one star) and any planets and other materials that orbit it.

a

A star is seen to have two transiting planets. Planet 1 transits every 3 months, and Planet 2 transits every 15 months. What can we infer about their orbits? a. Planet 2's semimajor axis is larger than Planet 1's. b. Planet 1's semimajor axis is larger than Planet 2's. c. Planet 1's orbit is more eccentric than Planet 2's. d. Planet 2's orbit is more eccentric than Planet 1's.

Why was it advantageous for the Voyager mission to consist of flybys rather than orbiters?

Each individual spacecraft was able to visit more than one planet.

The diffraction limit is a limit on ...

A telescope's angular resolution.

Which of the following statements best describes the difference between a refracting telescope and a reflecting telescope? A) A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light. B) A refracting telescope produces refracted images while a reflecting telescope produces reflected images. C) Reflecting telescopes make much clearer images than can refracting telescopes of the same size. D) It is much easier to make a large refracting telescope than a large reflecting telescope.

A) A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light.

Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light? A) Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light. B) Radio telescopes are designed to collect sound rather than light. C) It is because radio telescopes are used in the daytime and visible light telescopes are used at night. D) Objects that emit radio waves are always much larger than objects that emit visible light, and therefore require larger telescopes.

A) Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light.

What is the purpose of interferometry? A) It allows two or more small telescopes to achieve the angular resolution of a much larger telescope. B) It allows two or more small telescopes to achieve a larger light-collecting area than they would have independently . C) t is designed to prevent light pollution from interfering with astronomical observations. D) It reduces the twinkling of stars caused by atmospheric turbulence.

A) It allows two or more small telescopes to achieve the angular resolution of a much larger telescope.

What is a CCD? A) It is an electronic detector that can be used in place of photographic film for making images. B) It is an abbreviation for the world's largest operating telescope. C) It refers to any kind of instrument that can be hooked up to a telescope. D) It is a unit used by astronomers to measure angular resolution.

A) It is an electronic detector that can be used in place of photographic film for making images.

Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes? A) It is closer to the stars. B) Stars do not twinkle when observed from space. C) It can observe infrared and ultraviolet light, as well as visible light. D) It never has to close because of bad weather. E) Observers on the ground can use it at any time of day (i.e., not only during their night).

A) It is closer to the stars.

Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes? A) It is closer to the stars. B) Stars do not twinkle when observed from space. C) It can observe infrared and ultraviolet light, as well as visible light. D) It never has to close because of cloudy skies.

A) It is closer to the stars.

What is the purpose of adaptive optics? A) It reduces blurring caused by atmospheric turbulence for telescopes on the ground. B) It allows several small telescopes to work together like a single larger telescope. C) It is a special technology that allows the Hubble Space Telescope to adapt to study many different types of astronomical objects. D) It allows ground-based telescopes to observe ultraviolet light that normally does not penetrate the atmosphere.

A) It reduces blurring caused by atmospheric turbulence for telescopes on the ground.

Which planet has a ring system?

A) Jupiter B) Saturn C) Uranus D) Neptune

Consider two future observatories in space. Observatory X consists of a single 50-meter telescope. Observatory Y is an interferometer consisting of five 10-meter telescopes, spread out over a region 100 meters across. Which observatory can detect dimmer stars, and which one can see more detail in its images? (Assume all else is equal, such as quality of optics, types of instruments, and so on.) A) Observatory X can detect dimmer stars and Observatory Y reveals more detail in images. B) Observatory Y can detect dimmer stars and Observatory X reveals more detail in images. C) Observatory X both detects dimmer stars and reveals more detail in images. D) Observatory Y both detects dimmer stars and reveals more detail in images.

A) Observatory X can detect dimmer stars and Observatory Y reveals more detail in images.

Which of the following statements best describes the two principal advantages of telescopes over eyes? A) Telescopes can collect far more light with far better angular resolution. B) Telescopes can collect far more light with far greater magnification. C) Telescopes have much more magnification and better angular resolution. D) Telescopes collect more light and are unaffected by twinkling. E) Telescopes can see farther without image distortion and can record more accurate colors.

A) Telescopes can collect far more light with far better angular resolution.

Which of the following statements best describes the two principle advantages of telescopes over eyes? A) Telescopes can collect far more light with far better angular resolution. B) Telescopes can collect far more light with far greater magnification. C) Telescopes collect more light and are unaffected by twinkling. D) Telescopes have much more magnification and better angular resolution.

A) Telescopes can collect far more light with far better angular resolution.

Which of the following is not a major reason why astronomers would like an observatory on the far side of the Moon? A) Telescopes on the Moon could see objects in all parts of the sky equally well, whereas telescopes on Earth can see only portions of the sky that depend on their latitude. B) Radio astronomy would be advantageous on the Moon because human radio transmissions are less likely to cause interference, especially on the far side of the Moon. C) It would be possible to put telescopes for ultraviolet and X-ray astronomy on the surface, unlike the case on the surface of the Earth. D) Telescopes on the Moon could observe stars even when it is daytime on the Moon.

A) Telescopes on the Moon could see objects in all parts of the sky equally well, whereas telescopes on Earth can see only portions of the sky that depend on their latitude.

How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope? A) The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope. B) The 8-meter telescope has 4 times the light-collecting area of the 2-meter telescope. C) The 8-meter telescope has 8 times the light-collecting area of the 2-meter telescope. D) The answer cannot be determined from the information given in the question.

A) The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope.

Which of the following telescopes would benefit most from adaptive optics? A) The Keck I Telescope on Mauna Kea. B) The Hubble Space Telescope. C) The Arecibo Radio Telescope in Puerto Rico. D) The Chandra X-Ray Observatory.

A) The Keck I Telescope on Mauna Kea.

Suppose you have two small photographs of the Moon. Although both look the same at small size, when you blow them up to poster size one of them still looks sharp while the other one becomes fuzzy (grainy) looking. Which of the following statements is true? A) The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy . B) The one that looks fuzzy at large size has better angular resolution (smaller) than the one that looks sharp. C) Both photographs have the same angular resolution, because they were both printed at the same sizes in each case. D) Both photographs have the same angular resolution, because they are both photographs of the same object.

A) The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy .

Suppose you point your telescope at a distant object. Which of the following is not an advantage of taking a photograph of the object through the telescope as compared to just looking at the object through the telescope? A) The photograph will have far better angular resolution than you can see with your eye. B) By using a long exposure time, the photograph can allow you to see objects that would be too dim to see with your eye. C) If taken with a camera with a sensitive detector such as a CCD, the photograph can capture a much larger percentage of the incoming photons than can your eye. D) The photograph provides a more reliable record of what is seen through the telescope than can a drawing made by eye.

A) The photograph will have far better angular resolution than you can see with your eye.

Which of the following is not a reason why telescopes tend to be built on mountaintops that are relatively far from cities and are in regions with dry climates? A) The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping. B) Being on a high mountain top means being relatively high in the atmosphere, which tends to limit turbulence. C) Dry regions mean less rain and clouds, and mountaintops in dry regions may even allow some infrared observations. D) Mountaintops far from cities are generally subject to less light pollution than locations nearer to cities.

A) The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.

Which of the following is always true about images captured with X-ray telescopes? A) They are always shown with colors that are not the true colors of the objects that were photographed. B) They always are made with adaptive optics. C) They show us light with extremely long wavelengths compared to the wavelengths of visible light. D) They always have very high angular resolution. E) They are always very pretty.

A) They are always shown with colors that are not the true colors of the objects that were photographed.

What is an artificial star? A) a point of light in Earth's atmosphere created by a laser for the purpose of monitoring atmospheric fluctuations B) a satellite orbiting Earth C) a meteor D) a possible source of dark matter in the universe E) the unseen member of a binary star system

A) a point of light in Earth's atmosphere created by a laser for the purpose of monitoring atmospheric fluctuations

Order the following in order of increasing efficiency of detecting photons of visible light. A) eye, photographic film, CCD B) photographic film, CCD, eye C) CCD, eye, photographic film D) CCD, photographic film, eye E) eye, CCD, photographic film

A) eye, photographic film, CCD

Which of the following is not one of the three main categories of observation generally used by astronomers? A) filtering to look at just a single color from an object B) timing to track how an object's brightness varies with time C) spectroscopy to spread an object's light into a spectrum D) imaging to get a picture of an astronomical objects

A) filtering to look at just a single color from an object

At which wavelength range is there no current or planned space observatory? A) radio B) infrared C) visible D) X-ray E) gamma-ray

A) radio

Which of the following wavelength regions can be studied with telescopes on the ground? A) radio, visible, and very limited portions of the infrared and ultraviolet regions B) all light with wavelengths longer than ultraviolet wavelengths C) all light with wavelengths shorter than infrared wavelengths D) infrared, visible, and ultraviolet light

A) radio, visible, and very limited portions of the infrared and ultraviolet regions

What does angular resolution measure? A) the angular size of the smallest features that the telescope can see B) the brightness of an image C) the size of an image D) the number of electromagnetic waves captured by an image

A) the angular size of the smallest features that the telescope can see

Which of the following could not be measured by an observation that uses only imaging? A) the rate at which a variable star brightens and dims B) the general shape of an interstellar cloud of gas C) the color of a planet D) the brightness of a star in our sky E) the number of bright stars in a nearby star cluster

A) the rate at which a variable star brightens and dims

The stars in our sky twinkle in brightness and color because of ________. A) turbulence in the Earth's atmosphere B) rapid changes in the brightnesses and colors of stars caused by changes in their spectra C) light pollution D) the bubbling and boiling of gases on the surfaces of stars

A) turbulence in the Earth's atmosphere

Which of the following effects is caused by atmospheric turbulence? A) twinkling of stars B) light pollution C) magnification of images D) diffraction of light

A) twinkling of stars

On a scale where the Sun is about the size of a grapefruit and the Earth is about 15 meters away, how far away are the nearest stars besides the Sun?

About the distance across the United States

The Hubble Space Telescope obtains higher-resolution images than most ground-based telescopes because it is ...

Above Earth's atmosphere.

a

According to modern science, approximately how old is the Sun? a. 4.5 billion years b. 25 million years c. 400 million years d. 11,000 years

a

According to modern scientific dating techniques, approximately how old is the solar system? a. 4.5 billion years b. 14 billion years c. 10,000 years d. 4.6 million years

c

According to our theory of solar system formation, what are asteroids and comets? a. chunks of rock or ice that condensed after the planets and moons finished forming b. chunks of rock or ice that were expelled from planets by volcanoes c. leftover planetesimals that never accreted into planets d. the shattered remains of collisions between planets

a

According to our theory of solar system formation, what three major changes occurred in the solar nebula as it shrank in size? a. It got hotter, its rate of rotation increased, and it flattened into a disk. b. Its mass, temperature, and density all increased. c. It gained energy, it gained angular momentum, and it flattened into a disk. d. Its gas clumped up to form the terrestrial planets, nuclear fusion produced heavy elements to make the jovian planets, and central temperatures rose to more than a trillion Kelvin.

c

According to our theory of solar system formation, what three major changes occurred in the solar nebula as it shrank in size? a. Its mass, temperature, and density all increased. b. It gained energy, it gained angular momentum, and it flattened into a disk. c. It got hotter, its rate of rotation increased, and it flattened into a disk. d. Its gas clumped up to form the terrestrial planets, nuclear fusion produced heavy elements to make the jovian planets, and central temperatures rose to more than a trillion Kelvin.

a

According to our theory of solar system formation, why do all the planets orbit the Sun in the same direction and in nearly the same plane? a. The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk. b. The original solar nebula happened to be disk-shaped. c. Any planets that once orbited in the opposite direction or a different plane were ejected from the solar system. d. We would expect that a very small fraction of all planetary systems would have planets orbiting in such a pattern, so ours turned out that way due to random chance. e. The Sun formed first, and as it grew in size it spread into a disk, rather like the way a ball of dough can be flattened into a pizza by spinning it.

a

According to scientists, the naturally occurring greenhouse effect makes Earth about 31∘C warmer than it would be if there were no greenhouse gases in our atmosphere. How do scientists "know" what Earth's temperature would be without greenhouse gases? a. They calculate this temperature from Earth's reflectivity and distance from the Sun. b. They estimate it by averaging guesses made by many individual scientists. c. Ancient fossils allow them to infer Earth's temperature at a time before our atmosphere contained greenhouse gases. d. They assume that this temperature would be about the same as the temperature of Mars, which has much less of an atmosphere than Earth.

Which technology can allow a single ground-based telescope to achieve images as sharp as those from the Hubble Space Telescope?

Adaptive optics

Which jovian planet does not have rings?

All the jovian planets have rings.

Which of the following regions of the elctromagnetic spectrum is useful for studying distant galaxies?

All of the above

b

All of the following statements are true. Which one explains why Mars has lost so much more interior heat than Earth. a. Mars has a much weaker greenhouse effect than Earth. b. Mars is smaller than Earth. c. Mars has lost much more atmospheric gas than Earth. d. Mars is farther from the Sun than Earth. e. Mars lacks a large moon.

a

All of the following statements are true. Which one provides strong observational support for the claim that greenhouse gases make a planet warmer than it would be otherwise? a. Venus has a higher average temperature than Mercury. b. Earth has a higher average temperature than Mars. c. Earth is the only planet with an ozone layer in its atmosphere. d. Mercury is much hotter than the Moon.

Which of the following is not a general difference between a planet and a star?

All planets are made of rock and all stars are made of gas.

Shown following are five different colors of visible light that travel to Earth from the Sun. Rank these colors of visible light from left to right based on the altitude in the atmosphere where they are completely absorbed, from highest to lowest (Earth's surface). If two (or more) of the choices reach the surface, rank them as equal by dragging one on top of the other(s).

All stacked on each other

Shown following are the primary mirror arrangements and total light-collecting area of five different telescopes. Each mirror uses a different segmented arrangement, but assume that they are all equivalent in quality and in their ability to focus light. Also assume that the telescopes use identical detectors and have the same observing conditions. Rank the telescopes from left to right based on their ability to detect very dim objects, from greatest to least. To rank two (or more) telescopes as equal, drag one on top of the other(s).

All stacked on each other

Shown following are the primary mirror arrangements and total light-collecting area of five different telescopes. Notice that although the arrangements look similar to those in Part B, the light-collecting areas are not the same. Also listed is an amount of time (exposure time) that each telescope will be pointed at the same distant galaxy. Again assume that the quality of these mirrors, the detectors, and the observing conditions are identical. Rank the telescopes from left to right based on the brightness of the image each telescope will take of the galaxy in the time indicated, from brightest to dimmest. To rank two (or more) telescopes as equal, drag one on top of the other(s).

All stacked on each other

1,4,5

All the following statements are true. Which of them are considered to be "exceptions" to the general trends described by the first three major features of the solar system? Check all that apply. 1. Our Moon has a diameter more than 1/4 the diameter of Earth. 2. Jupiter's largest moon, Ganymede, is even larger than Earth's moon. 3. Pluto is in the outer solar system but is ice-rich in composition. 4. Venus rotates in a direction opposite to the rotation of the other terrestrial planets. 5. Uranus rotates with an axis tilt that lies nearly in the ecliptic plane.

The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane.

All the following statements are true. Which one explains the reason that there is not a solar eclipse at every new moon?

Which jovian planet does not have rings?

All the jovian planets have rings

a

Although the Sun does not generate energy by gravitational contraction today, this energy-generation mechanism was important when the Sun was forming. a. True b. False

Which of the following transitions within an atom is not possible?

An electron begins in an excited state and then gains enough energy to jump to the ground state.

Suppose you look at a spectrum of visible light by looking through a prism or diffraction grating. How can you decide whether it is an emission line spectrum or an absorption line spectrum?

An emission line spectrum consists of bright lines on a dark background, while an absorption line spectrum consists of dark lines on a rainbow background.

d

An icy leftover planetesimal orbiting the Sun is a. an asteroid. b. a meteor. c. a meteorite. d. a comet. e. possibly any of the above

Which of the following changes would cause the fusion rate in the Sun's core to increase? Check all that apply. An increase in the core temperature An increase in the core radius A decrease in the core temperature A decrease in the core radius

An increase in the core temperature & A decrease in the core radius An increase in the core temperature increases the fusion rate because the fusion rate is very sensitive to temperature. A decrease in the core radius causes the core to heat up and increase in density, which therefore leads to an increased fusion rate.

moon

An object that orbits a planet.

moon (or satellite)

An object that orbits a planet. The term satellite is also used more generally to refer to any object orbiting another object.

The Cassini mission to Saturn consists of:

An orbiter that orbits Saturn and a probe that descended to the surface of Titan.

satellite

Any object orbiting another object.

carried the first humans to the Moon on July 20, 1969

Apollo II

b

As discussed in the video, the leading hypothesis for why Mars changed holds that interior cooling led to loss of its magnetosphere, allowing the solar wind to strip atmospheric gas away. How has the MAVEN mission provided evidence for this hypothesis? a. It has measured the strength of the magnetic field that Mars had long ago. b. It has measured rates of gas loss from the atmosphere today. c. It measured the amount of atmospheric gas that Mars had long ago. d. It has measured the rate at which Mars's interior has lost heat.

d

As you found in Part A, early Mars had both core convection and a strong magnetosphere. What is the connection between these two things? a. Both core convection and a magnetosphere can exist only a very young planet. b. Core convection creates volcanism and outgassing, the gas creates the magnetosphere. c. Both core convection and a magnetosphere are consequences of a strong greenhouse effect. d. Core convection helps generate a magnetic field, and the magnetic field creates the magnetosphere.

d

As you've seen, the nebular theory predicts that a cloud that gives birth to planets should have the shape of a spinning disk. Which observable property of our solar system supports this prediction? a. There are two basic types of planets in our solar system: terrestrial and jovian. b. The orbit of Earth's Moon lies very close to the ecliptic plane. c. The four largest planets all have disk-shaped ring systems around them. d. All the planets orbit the Sun in the same direction and in nearly the same plane.

1,3,5

Assume that the migration hypothesis is the correct explanation for the hot Jupiters. In that case, the revised nebular theory looks just like the old theory, except that it now allows for the possibility of migration. Which of the following statements are consistent with this revised theory? Check all that apply. 1. Jovian planets can migrate inward and disrupt the orbits of terrestrial planets. 2. Hot Jupiters can orbit their star in a direction opposite that of other jovian planets in the same system. 3. Terrestrial planets always form in the warm, inner regions of their star system. 4. Our solar system must be unusual because the jovian planets did not migrate inward. 5. Jovian planets always form in the cold, outer regions of their star system.

Which of the following most clearly distinguishes asteroids and comets from planets?

Asteroids and comets are much smaller than planets.

How do asteroids differ from comets?

Asteroids are rocky bodies and are denser than the comets, which are made of icy material.

Which of the following is not a real difference between asteroids and comets?

Asteroids orbit the Sun while comets just float randomly around in the Oort cloud.

c

At the center of the Sun, fusion converts hydrogen into a. plasma. b. radiation and elements like carbon and nitrogen. c. helium, energy, and neutrinos.

Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms different isotopes of the same element?

Atom 1: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons; Atom 2: nucleus with 7 protons and 7 neutrons, surrounded by 7 electrons

Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms different isotopes of the same element? Atom 1: nucleus with 4 protons and 5 neutrons, surrounded by 4 electrons; Atom 2: nucleus with 5 protons and 5 neutrons, surrounded by 4 electrons Atom 1: nucleus with 8 protons and 8 neutrons, surrounded by 8 electrons; Atom 2: nucleus with 8 protons and 8 neutrons, surrounded by 7 electrons Atom 1 : nucleus with 6 protons and 8 neutrons, surrounded by 6 electrons; Atom 2: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons Atom 1: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons; Atom 2: nucleus with 7 protons and 7 neutrons, surrounded by 7 electrons

Atom 1: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons; Atom 2: nucleus with 7 protons and 7 neutrons, surrounded by 7 electrons They are isotopes both atoms have the same atomic number but different atomic mass numbers.

What do we mean when we say that the universe is expanding?

Average distances between galaxies are increasing with time.

Which of the following best describes the principle advantage of CCDs over photographic film? A) CCDs allow long exposures (e.g., minutes or hours) and film does not. B) CCDs capture a much higher percentage of the incoming photons than film. C) CCDs can record the colors of astronomical objects accurately while film cannot. D) CCDs can be attached to modern telescopes more easily than can photographic film.

B) CCDs capture a much higher percentage of the incoming photons than film.

Telescopes operating at this wavelength must be cooled to observe faint astronomical objects. A) radio B) extreme infrared C) visible D) X-ray E) gamma-ray

B) extreme infrared

What does the technique of interferometry allow? A) It allows two or more telescopes to obtain a total light-collecting area much larger than the total light- collecting area of the individual telescopes. B) It allows two or more telescopes to obtain the angular resolution of a single telescope much larger than any of the individual telescopes. C) It allows us to determine the chemical composition of stars. D) It allows astronomers to make astronomical observations without interference from light pollution. E) It allows the same telescope to make images with both radio waves and visible light.

B) It allows two or more telescopes to obtain the angular resolution of a single telescope much larger than any of the individual telescopes.

What is meant by spectral resolution? A) It is a measure of how much energy an object emits in different parts of the electromagnetic spectrum. B) It is a measure of how close two spectral lines can be distinguished. C) It is a measure of how close two point sources can be distinguished. D) It is the same as angular resolution when applied to telescopes operating at different wavelengths.

B) It is a measure of how close two spectral lines can be distinguished.

What do we mean by the diffraction limit of a telescope? A) It describes the farthest distance to which the telescope can see. B) It is the angular resolution the telescope could achieve if nothing besides the size of its light-collecting area affected the quality of its images. C) It is the maximum size to which any telescope can be built. D) It describes the maximum exposure time for images captured with the telescope.

B) It is the angular resolution the telescope could achieve if nothing besides the size of its light-collecting area affected the quality of its images.

Which of the following best describes what we mean by the focal plane of a telescope? A) It is the upper surface of the telescope's primary lens or mirror. B) It is the place where, if we mounted film or an electronic detector, we could get a clear (not blurry) image of an object viewed through the telescope. C) It is the lower surface of the telescope's primary lens or mirror. D) It is the surface of the lens on the eyepiece, through which you would look to see objects in the telescope's field of view.

B) It is the place where, if we mounted film or an electronic detector, we could get a clear (not blurry) image of an object viewed through the telescope.

What do astronomers mean by light pollution? A) Light pollution is a type of air pollution created by lightweight gases such as hydrogen and helium. B) Light pollution is light from human sources that makes it difficult to see the stars at night. C) Light pollution means contamination of light caused by chemicals in the Earth's atmosphere. D) Light pollution is a term used to describe the appearance of the sky in regions that are crowded with stars.

B) Light pollution is light from human sources that makes it difficult to see the stars at night.

Suppose the angular separation of two stars is smaller than the angular resolution of your eyes. How will the stars appear to your eyes? A) You will not be able to see these two stars at all. B) The two stars will look like a single point of light. C) The two stars will appear to be touching, looking rather like a small dumbbell. D) You will see two distinct stars. E) You will see only the larger of the two stars, not the smaller one.

B) The two stars will look like a single point of light.

The Chandra X-Ray Observatory must operate in space because: A) X rays are too dangerous to be allowed on the ground. B) X rays do not penetrate Earth's atmosphere. C) X-ray telescopes require the use of grazing incidence mirrors. D) It was built by NASA.

B) X rays do not penetrate Earth's atmosphere.

Which of the following studies is best suited to astronomical observations that fall into the category called timing? A) studying how different planets differ in their surface compositions B) studying how a star's brightness varies over a period of 3 years C) measuring the rotation rate of a distant star D) determining the age of the solar system

B) studying how a star's brightness varies over a period of 3 years

Which of the following studies is best suited to a timing experiment? A) studying how different stars differ in their chemical compositions B) studying whether a particular star's brightness is steady or variable C) determining the age of the solar system D) measuring the rotation rate of a distant star E) estimating the time since the Big Bang

B) studying whether a particular star's brightness is steady or variable

What is the purpose of adaptive optics? A) to improve the angular resolution of telescopes in space B) to eliminate the distorting effects of atmospheric turbulence for telescopes on the ground C) to increase the collecting area of telescopes on the ground D) to increase the magnification of telescopes on the ground E) to allow several small telescopes to work together like a single larger telescope

B) to eliminate the distorting effects of atmospheric turbulence for telescopes on the ground

c

Based on our current theory of Earth's formation, the water we drink likely comes from a. material left behind during the giant impact that formed the Moon. b. chemical reactions that occurred in Earth's core after Earth formed. c. water bearing planetesimals that impacted Earth. d. chemical reactions that occurred in Earth's crust after Earth formed. e. ice that condensed in the solar nebula in the region where Earth formed.

1,2,3,4

Based on the nebular theory as it explains our own solar system, which of the following should we expect to be true for other star systems? Check all that apply. 1. Planetary systems should be common. 2. Planetary systems should generally have all planets orbiting in nearly the same plane. 3. Jovian planets always form farther from their star than terrestrial planets. 4. Many extrasolar planets should fall into the terrestrial or jovian categories. 5. Planetary systems will always have four terrestrial planets and four jovian planets. 6. Some planetary systems will have terrestrial planets that orbit their star in a direction opposite to the orbital direction of the jovian planets.

d

Based on what we know about our own solar system, the discovery of hot Jupiters came as a surprise to scientists because these planets are __________. a. so small b. made of different materials than either the terrestrial or jovian planets in our solar system c. so large d. so close to their stars

d

Based solely on an understanding of the greenhouse effect (as displayed in the figure), which one of the following statements is true? a. Global warming poses a grave threat to our future. b. We do not yet understand the greenhouse effect well enough to make predictions about how it affects our planet. c. Humans are causing global warming. d. We should expect an increase in the greenhouse gas concentration to lead to global warming.

Venus has a higher average surface temperature than Mercury. Why?

Because its surface is heated by an extreme greenhouse effect.

Why do the patterns of the stars in our sky look the same from year to year?

Because the stars in the constellations are so far away.

In what way is Venus most similar to Earth?

Both planets are nearly the same size.

Which of the following is a principal advantage of CCDs over photographic film? A) CCDs allow long exposures (e.g., minutes or hours), and film does not. B) CCDs can record the colors of astronomical objects accurately, while film cannot. C) CCDs capture a much higher percentage of the incoming photons than does film. D) Images recorded with CCDs never require any image processing, while images recorded by film often do. E) CCDs can be attached to modern telescopes more easily than cameras.

C) CCDs capture a much higher percentage of the incoming photons than does film.

What do astronomers mean by light pollution? A) Light pollution refers to pollution caused by light industry as opposed to heavy industry. B) Light pollution refers to harmful gases emitted by common street lights. C) Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations. D) Light pollution refers to the lights that must be used inside major observatories and that make it difficult for astronomers' eyes to adapt to darkness. E) Light pollution is another name for sunlight, which makes it impossible to see stars in the daytime.

C) Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations.

Why do astronomers need different telescope designs to observe across the electromagnetic spectrum? A) New telescopes incorporate new technology to increase their efficiency. B) Telescopes have to adapt to the greater distortion of the atmosphere at shorter wavelengths. C) Photons of different energy behave differently and require different collection strategies. D) Light pollution is worse at radio wavelengths than visible wavelengths. E) Astronomers and engineers enjoy the challenge of making new telescope designs.

C) Photons of different energy behave differently and require different collection strategies.

The angular separation of two stars is 0.1 arcseconds and you photograph them with a telescope that has an angular resolution of 1 arcsecond. What will you see? A) The two stars will appear to be touching, looking rather like a small dumbbell. B) The stars will not show up at all in your photograph. C) The photo will seem to show only one star rather than two. D) You will see two distinct stars in your photograph.

C) The photo will seem to show only one star rather than two.

Which of the following best describes the development of astronomical telescopes over the past 60 years? A) Over the 60-year period, telescopes have gradually gotten bigger and more powerful. B) Although there have been advances in cameras and computing power, telescopes themselves have not changed much in the last 60 years. C) The world's most powerful telescope remained the same for most of this period, but in the past 20 years many new and more powerful telescopes have been built. D) The only major change in telescope power has occurred because of our ability to launch telescopes into space rather than operating them only from the ground.

C) The world's most powerful telescope remained the same for most of this period, but in the past 20 years many new and more powerful telescopes have been built.

What is the angular resolution of the human eye? A) about 1 degree B) about 1 arcsecond (1/3600 of a degree) C) about 1 arcminute, or 1/60 of a degree D) about 1 milliarcsecond

C) about 1 arcminute, or 1/60 of a degree

Which of the following is a principal advantage of CCDs over photographic film?

CCDs capture a much higher percentage of the incoming photons than does film.

d

Complete this statement. The larger the decrease in the star's brightness as the planet transits in front of a star, _______. a. the larger the size of the star. b. the larger the distance to the star. c. the larger the size of the planet's orbit. d. the larger the size of the planet.

is currently in orbit around Saturn

Cassini

Consider an atom of oxygen in which the nucleus contains 8 protons and 8 neutrons. If it is doubly ionized, what is the charge of the oxygen ion and how many electrons remain in the ion?

Charge = +2; number of remaining electrons = 6.

2,4,5

Consider the first major feature (orderly motions). Which of the following correctly describe patterns of motion in our solar system? Select all that apply. 1. Inner planets orbit the Sun in the opposite direction from the outer planets. 2. Planets have nearly circular orbits. 3. The outer planets are so large that they nearly collide with each other on each orbit. 4. The Sun and most of the planets rotate in the same direction that the planets orbit. 5. All the planets orbit the Sun in nearly the same plane. 6. Major moons generally have polar orbits, meaning orbits that take them over the north and south poles of the planet they orbit.

c

Consider the planet that causes the stellar motion shown in Plot 2 (be sure you have clicked the "Plot 2" button in the lower window of the animation). What can be said about a different planet orbiting the same star with an orbital period of 500 days? a. The planet must be more massive. b. The planet must be less massive. c. The planet must be closer to the star. d. The planet must be farther from the star.

Following are the different layers of the Sun's atmosphere. Rank them based on the order in which a probe would encounter them when traveling from Earth to the Sun's surface, from first encountered to last. Corona chromosphere photosphere

Corona chromosphere photosphere

Rank the layers of the Sun's atmosphere based on their temperature, from highest to lowest Corona chromosphere photosphere

Corona chromosphere photosphere Scientists were quite surprised when they first learned that the temperature increases with altitude in the Sun's atmosphere, and even today the heating mechanism is not fully understood. However, we know that magnetic fields play an important role in transporting heat upward, making the chromosphere hotter than the photosphere and the corona hotter still.

Rank the layers of the atmosphere based on the energy of the photons that are typically emitted there, from highest to lowest. Corona chromosphere photosphere

Corona chromosphere photosphere The energy of the emitted light rises with temperature, so the ranking for this question is the same as that of Part C. In fact, the photosphere emits primarily visible light, the chromosphere primarily ultraviolet light, and the corona primarily X rays. This is why astronomers study the corona with X-ray telescopes and the chromosphere with ultraviolet telescopes, while we observe the photosphere with visible-light telescopes.

Currently, the largest optical telescope mirrors have a diameter of A) 1 m. B) 2 m. C) 5 m. D) 10 m. E) 100 m.

D) 10 m.

What do we mean by the diffraction limit of a telescope? A) It is the maximum size to which any telescope can be built. B) It describes the farthest distance to which the telescope can see. C) It describes the maximum exposure time for images captured with the telescope. D) It is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion.

D) It is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion.

Which of the following statements about light focusing is not true? A) In a healthy eye, light is focused on the retina. B) Film should be placed at the focal plane in a camera. C) If you try to look at an image that is not formed at the focal plane, it will be blurry. D) The focal plane of a reflecting telescope is always located within a few inches of the primary mirror.

D) The focal plane of a reflecting telescope is always located within a few inches of the primary mirror.

Which of the following is always true about images captured with X-ray telescopes? A) They are always very pretty. B) They are always displayed with the highest possible angular resolution. C) They are always useful for seeing through things. D) They are always displayed in false color. E) They are always displayed with north pointing upward in the images.

D) They are always displayed in false color.

What causes stars to twinkle? A) It is intrinsic to the stars—their brightness varies as they expand and contract. B) variations in the absorption of the atmosphere C) variable absorption by interstellar gas along the line of sight to the star D) bending of light rays by turbulent layers in the atmosphere E) the inability of the human eye to see faint objects

D) bending of light rays by turbulent layers in the atmosphere

Which of the following wavelength regions cannot be studied with telescopes on the ground? A) radio waves B) ultraviolet C) X rays D) both B and C E) both A and C

D) both B and C

Suppose you want to determine the chemical composition of a distant planet or star. Which of the following will be most useful to have? A) high angular resolution B) high turbulence C) a radio telescope D) high spectral resolution

D) high spectral resolution

Which of the following is not a good reason to place observatories on remote mountain tops? A) to reduce light pollution B) to reduce light distortion C) to reduce light absorption D) to be able to observe at radio wavelengths E) to be able to observe at infrared wavelengths

D) to be able to observe at radio wavelengths

If our eyes were sensitive only to X rays, the world would appear

Dark because X-ray light does not reach Earth's surface

Earth is catching up with and passing by Mars in their respective orbits.

During the period each year when we see Mars undergoing apparent retrograde motion in our sky, what is really going on in space?

The largest effective telescope, created by radio interferometry, is the size of A) several football fields, in a natural depression in Puerto Rico. B) tens of miles across, in the deserts of New Mexico. C) the state of New Mexico. D) the continental United States. E) Earth.

E) Earth.

Which of the following could not be determined by an observation that uses only spectroscopy? A) the chemical composition of a distant star B) the speed at which a distant galaxy is moving away from us C) the surface temperature of a distant star D) the rotation rate of a distant star E) the size of a distant galaxy

E) the size of a distant galaxy

Which is the densest planet in the solar system?

Earth

An astronomical unit is

Earth's average distance from the Sun

How do the speeds at which we are moving with Earth's rotation and orbit compare to the speeds of more familiar objects?

Earth's rotation carries most people around the axis faster than a commercial jet travels, and Earth's orbit carries us around the Sun faster than the Space Shuttle orbits Earth.

3,4,5

Earth's temperature remains fairly steady, which means that Earth must return nearly the same amount of energy to space that it receives from the Sun. In what form(s) does Earth return most of this energy to space? Check all that apply. 1. visible light emitted by the surface and atmosphere 2. ultraviolet light reflected by the surface 3. visible light reflected by clouds 4. visible light reflected by the surface 5. infrared light emitted by the surface and atmosphere

Which of the following correctly lists our "cosmic address" from small to large?

Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe

Which of the following statements about electrons is not true?

Electrons orbit the nucleus rather like planets orbiting the Sun.

Which of the following statements about electrons is not true? Within an atom, an electron can have only particular energies. Electrons have very little mass compared to protons or neutrons. Electrons orbit the nucleus rather like planets orbiting the Sun. An electron has a negative electrical charge. Electrons can jump between energy levels in an atom only if they receive or give up an amount of energy equal to the difference in energy between the energy levels.

Electrons orbit the nucleus rather like planets orbiting the Sun.

b

Energy balance in the Sun refers to a balance between _________. a. the mass that the Sun loses each second and the amount of mass converted into energy each second. b. the rate at which fusion generates energy in the Sun's core and the rate at which the Sun's surface radiates energy into space c. the force of gravity pulling inward and the force due to pressure pushing outward d. the amount of energy the Sun radiates into space and the amount of energy that reaches Earth

c

Energy moves through the Sun's _____ by means of the rising of hot gas and falling of cooler gas. a. photosphere b. radiation zone c. convection zone d. chromosphere

The term seeing is used to describe how faint an object can be detected by a telescope

False

Because gamma rays have very short wavelengths, gamma-ray telescopes can achieve extremely high angular resolution

False

Professional astronomical telescopes generally have a much greater magnification than the telescopes you can buy in stores.

False

Which of the following is not one of the three main categories of observation generally used by astronomers?

Filtering to look at just a single color from an object.

If you had only one telescope and wanted to take both visible-light and ultraviolet pictures of stars, where should you locate your telescope?

In space

Earth is stationary at the center of the universe

For most of history, the lack of observable stellar parallax was interpreted to mean that _________.

How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope?

Four times

How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope?

Four(4) times

When the temperature of the Sun's core goes down, what happens next? Fusion reactions speed up; the core expands and cools. Fusion reactions slow down; the core expands and heats. Fusion reactions slow down; the core shrinks and heats. Fusion reactions speed up; the core shrinks and cools.

Fusion reactions slow down; the core shrinks and heats.

How are galaxies important to our existence?

Galaxies recycle material from one generation of stars to the next, and without this recycling we could not exist.

dropped a probe into Jupiter on December 7, 1995

Galileo

has been collecting high-resolution images of Jupiter and its moons since 1995

Galileo Orbiter

c

Greenhouse gases in the atmosphere, such as carbon dioxide and water vapor, make Earth warmer than it would be otherwise because these gases __________. a. form clouds that emit thermal radiation b. absorb visible light coming from the Sun c. absorb infrared light emitted by the surface d. reflect visible light coming from the Sun

Suppose you want to determine the chemical composition of a distant planet or star. Which of the following will be most useful to have?

High spectral resolution.

How is Einstein's famous equation, E=mc2, important in understanding the Sun?

It explains the fact that the Sun generates energy to shine by losing some 4 million tons of mass each day.

In which case will the woman see a rainbow of color interrupted by a few dark absorption lines?

Hot light source and thin cloud of cool gas The hot light source produces a continuous spectrum, but the cool gas absorbs light at specific wavelengths, so that she sees an absorption line spectrum.

It doesn't --- Earth's orbital distance plays no significant role in the seasons.

How does Earth's varying distance from the Sun affect our seasons?

c

How is carbon dioxide initially removed from the atmosphere? a. formation of carbonate-rich rocks at the seafloor b. subduction c. dissolving carbon dioxide in water d. photosynthesis in plants

the only spacecraft listed that remains in Earth's orbit

Hubble Space telescope

According to our modern science, which of the following best explains why the vast majority of the mass of our solar system consists of hydrogen and helium gas?

Hydrogen and helium are the most common elements throughout the universe, because they were the only elements present when the universe was young.

the four seasons would each be twice as long as they are now

If our year were twice as long (that is, if Earth took twice as many days to complete each orbit around the Sun), but Earth's rotation period and axis tilt were unchanged, then _________.

c

If the freezing point of all ices was at a much lower temperature, what change would that imply for the formation of our solar system? a. The gas giants could have formed closer to the sun. b. The gas giants could not have formed at all. c. The gas giants would have to form at a larger distance from the sun. d. There would be no change in where gas giants could form, because the freezing point of ices did not aect the formation of gas giants.

Which of the following must occur for a star's core to reach equilibrium after an initial change in fusion rate? Check all that apply. If the fusion rate initially decreases, then the core expands. If the fusion rate initially increases, then the core expands. If the fusion rate initially decreases, then the core contracts. If the fusion rate initially increases, then the core contracts.

If the fusion rate initially increases, then the core expands. If the fusion rate initially decreases, then the core contracts. Increasing the fusion rate releases more energy into the core, which raises the temperature and increases the internal pressure, causing the core to expand. Decreasing the fusion rate means less energy is released, so the temperature and internal pressure decreases. As you can see in the interactive figure, the solar thermostat keeps the fusion rate fairly steady in a star like the Sun because a temperature increase causes the core to expand while a temperature decrease causes the core to contract.

Part A Sort each of the astronomical questions below into the appropriate bin based on the type of observation you would need to perform to answer it.

Imaging: How large is the Andromeda Galaxy? What are the major surface features of Mars? Are stars in the Orion Nebula surrounded by gas? Spectroscopy: What is the chemical composition of the Crab Nebula? What is the temperature of Jupiter's atmosphere? Is the star Vega moving toward us or away from us? Timing: Does the star Mira vary in brightness? Is the X-ray emission from the galactic center steady or changing?

One of the first steps is to choose what type of observation to make. Recall that three basic types of astronomical observation are imaging (taking a photograph of an object), spectroscopy (spreading an object's light into a spectrum), and timing (measuring how an object's light varies with time). ---Sort each of the astronomical questions below into the appropriate bin based on the type of observation you would need to perform to answer it.

Imaging= how large is the andromeda galaxy? =are stars in the Orion Nebula surrounded by dusty disks of gas? =what are the major surface features of mars? Spectroscopy= what is the temperature of Jupiter's atmosphere? =is the star Vega moving toward us or away from us? =what is the chemical composition of the Crab Nebula? Timing= does the star Mira vary in brightness? =is the x-ray emission from the galactic center steady or changing?

Where should you put a telescope designed for ultraviolet observations?

In Earth orbit

our evening view of space depends on where Earth is located in its orbit around the Sun

In any particular place on Earth, certain constellations are visible in the evening only at certain times of the year because _________.

b

In essence, the Kepler mission is searching for extrasolar planets by____________. a. identifying spectral lines that look like what we expect to see from a planet rather than a star b. monitoring stars for slight dimming that might occur as unseen planets pass in front of them c. observing a star carefully enough to notice that it is experiencing a gravitational tug caused by an unseen planet d. obtaining high-resolution photographs of other star systems

c

In essence, the nebular theory holds that _________. a. nebulae are clouds of gas and dust in space b. the nebular theory is a discarded idea that imagined planets forming as a result of a near-collision between our Sun and another star c. our solar system formed from the collapse of an interstellar cloud of gas and dust d. the planets each formed from the collapse of its own separate nebula

e

In the context of studying major bodies of our solar system, what category of object does our Moon best fit? a. large comet b. small asteroid c. jovian planet d. jovian moon e. terrestrial world

a

In the greenhouse effect, what is the direct cause of extra heating of the Earth's surface? a. Additional carbon dioxide makes the atmosphere more opaque to infrared light, trapping more of the infrared light emitted by Earth. b. Additional carbon dioxide makes the atmosphere more dense, so heat passes through it more slowly. c. Additional carbon dioxide makes the atmosphere more transparent to infrared light, allowing the sun to more directly heat the surface.

e

In what way(s) has Pluto long been known to be different from the planets? a. It has a highly eccentric orbit. b. Its orbit is more inclined to the ecliptic plane. c. It is composed primarily of ices. d. It is far smaller than the terrestrial planets. e. All of the above

Different telescopes are optimized for observing different wavelengths of light, so another consideration in planning an observation is deciding what type of telescope to use.---Each of the following statements describes an astronomical measurement. Place each measurement into the appropriate bin based on the type of telescope you would use to make it.

Infrared Telescopes= determine the surface temperature of Venus. = study a dense cloud of cold gas in space. Visible Light Telescope= measure the brightness of a star that is similar to our Sun. = Obtain a spectrum of sunlight reflected by Mars. X-Ray Telescope= observe the hot (1-million K) gas in the Sun's corona. =look for high-energy radiation from a supernova. (Cool objects emit in the infrared. The Sun and similar stars emit mostly in the visible; reflected light from Mars is therefore also visible light. Very hot gas emits X rays, which have very high energy (with only gamma-ray photons having more energy for light)).

The James Webb Space Telescope is designed primarily to observe __________

Infrared light

Part B Each of the following statements describes an astronomical measurement. Place each measurement into the appropriate bin based on the type of telescope you would use to make it.

Infrared telescope: Determine the surface temperature of Venus. Steady a dense cloud of cold gas in space. Visible Light telescope: Obtain a spectrum of the sunlight reflected by Mars. Measure the brightness of a star that is similar to our Sun. X-ray telescope: Observe the hot (1-million K) gas in the Sun's corona. Look for high-energy radiation from a supernova.

b

Is it possible to determine the planet's mass from the star's velocity curve? a. no, because the star's spectrum cannot tell us about the planet b. yes, by measuring both the star's orbital period and its change in velocity over the orbit c. yes, by measuring only the change in the star's orbital velocity over the orbit d. yes, by measuring the star's orbital period only

Which of the following statements is true of green grass?

It absorbs red light and reflects green light.

Which of the following statements is true of green grass? It absorbs red light and emits green light. It means the lawn is healthy. It absorbs red light and reflects green light. It transmits all colors of light except green.

It absorbs red light and reflects green light.

What is the purpose of interferometry?

It allows two or more small telescopes to achieve the angular resolution of a much larger telescope

If you see the color red in an X-ray image from the Chandra X-Ray Observatory, it means ...

It depends: the colors are chosen arbitrarily to represent something about the X rays recorded by the telescope

How is Einstein's famous equation, E= mc2, important in understanding the Sun?

It explains the fact that the Sun generates energy to shine by losing some 4 million tons of mass each day.

According to our present theory of solar system formation, which of the following best explains why the solar nebula ended up with a disk shape as it collapsed?

It flattened as a natural consequence of collisions between particles in the nebula.

Which of the following is not true of Mercury?

It has been studied closely by more than a dozen NASA spacecraft.

Which of the following is not true of Mercury?

It has been studied closely by several NASA spacecraft.

What is meant by spectral resolution?

It is a measure of how close two spectral lines can be distinguished.

How does the Sun's mass compare with that of the planets?

It is a thousand times more massive than all the planets combined.

Relative to the age of the universe, how old is our solar system?

It is about one-third the age of the universe.

Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes?

It is closer to the stars.

Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes? It never has to close because of cloudy skies. It is closer to the stars. Stars do not twinkle when observed from space. It can observe infrared and ultraviolet light, as well as visible light.

It is closer to the stars. Distance to the stars has absolutely nothing to do with it, as should be apparent if you consider the scale of the solar system and the distances to stars to scale (as discussed in Chapter 1).

According to present understanding, which of the following statements about the solar wind is not true?

It is even stronger today than it was when the Sun was young.

Which of the following best describes what we mean by the focal plane of a telescope?

It is the place where, if we mounted film or an electronic detector, we could get a clear (not blurry) image of an object viewed through the telescope.

In what way is Pluto more like a comet than a planet?

It is made mostly of rock and ice.

Figure showing a laboratory spectrum on the top and four object spectra underneath. Consider the spectra of the four objects shown beneath the laboratory spectrum. Based on these spectra, what can you conclude about Object 1? It is a star with a thin upper atmosphere. It is a very hot object, with a temperature above 1 million K. It is composed mostly of hydrogen, helium, and iron. It is moving toward us. It is moving away from us.

It is moving toward us Notice that the lines in Object 1's spectrum are all to the right of those in the laboratory spectrum. You can tell that this indicates a redshift - which means the object is moving away - because red is on the right side of these spectra (and blue is on the left).

What is the Oort cloud?

It is not really a cloud at all, but rather refers to the trillion or so comets thought to orbit the Sun at great distances.

What do we mean by the diffraction limit of a telescope?

It is the angular resolution the telescope could achieve if nothing besides the size of its light-collecting area affected the quality of its images.

What do we mean by the diffraction limit of a telescope?

It is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion

Which of the following statements about Pluto is not true?

It is the largest and most massive object that is considered to be a dwarf planet.

Which of the following statements about Pluto is not true?

It is the largest known object that is considered to be a dwarf planet.

Why has NASA sent recent orbiters to Mars (such as Mars Reconnaissance Orbiter) on trajectories that required them to skim through Mars's atmosphere before settling into their final orbits?

It saves money because the spacecraft uses atmospheric drag to slow down rather than needing to carry enough fuel to slow by firing rocket engines.

Imagine that an alien spaceship crashed onto Earth. Which statement would most likely be true?

It would crash in the ocean.

Imagine that an alien spaceship crashed onto Earth. Which statement would most likely be true?

It would crash in the ocean.

Suppose you had molecular oxygen (O2) chilled enough so that it was in liquid form. Which of the following best describes the phase changes that would occur as you heated the liquid oxygen to high temperature?

It would evaporate into a gas, then the molecules would dissociate into individual oxygen atoms, then the atoms would become increasingly ionized as you continued to raise the temperature.

third quarter

It's 6 am and the Moon is at its highest point in your sky (crossing the meridian). What is the Moon's phase?

What is the Oort cloud?

It's not really a cloud at all, but rather refers to the trillion or so comets thought to orbit the Sun at great distances.

The jovian planets in our solar system are

Jupiter, Saturn, Uranus, and Neptune.

The jovian planets in our solar system are:

Jupiter, Saturn, Uranus, and Neptune.

Listed following are the names and mirror diameters for six of the world's greatest reflecting telescopes used to gather visible light. Rank the telescopes from left to right based on their light-collecting area from largest to smallest. For telescopes with more than one mirror, rank based on the combined light-collecting area of the mirrors.

Left to Right 1. Large Binocular Telescope Two 8.4-m mirrors 2. Keck1 : One 10-m mirror 3. Hobby-Ebberly : One 9.2-m mirror 4. Subaru One 8.3-m mirror 5. Gemini North: One 8.3-m mirror 6. Magellan 11: One 6.5-m mirror

c

Leftover ice-rich planetesimals are called a. asteroids. b. meteorites. c. comets.

What do astronomers mean by light pollution?

Light pollution is light from human sources that makes it difficult to see the stars at night.

If we double the diameter of a telescope's mirror, what happens to its light-gathering ability?

Light-gathering ability quadruples

Which planet (besides Earth) has been visited by the largest number of robotic spacecraft?

Mars

Which planet, other than Earth, has visible water ice on it?

Mars

c

Mars' atmosphere is mostly carbon dioxide. Why does it not experience a runaway greenhouse effect like Venus? a. Mars does not have enough additional water to magnify the warming. b. Mars is protected by its magnetic field. c. Mars' atmosphere is too thin.

dark matter

Matter that we infer to exist from its gravitational effects but from which we have not detected any light; dark matter apparently dominates the total mass of the universe.

The terrestrial planets in our solar system are

Mercury, Venus, Earth, and Mars.

The terrestrial planets in our solar system are:

Mercury, Venus, Earth, and Mars.

The most metal-rich terrestrial planet is

Mercury.

d

Most of the Moon's surface is densely covered with craters, but we find relatively few craters within the lunar maria. What can we conclude? a. The maria formed within the past 1 billion years. b. Erosion affects the maria more than it affects other regions of the Moon. c. The regions of the maria were hit by fewer impacts than the densely cratered regions. d. The maria formed after the heavy bombardment ended.

c

Most of the Sun's ultraviolet light is emitted from the narrow layer called the _____ where temperature increases with altitude. a. core b. convection zone c. chromosphere d. radiation zone

The twinkling of stars is caused by ...

Motion of air in our atmosphere.

If you wanted a radio telescope to achieve the same angular resolution as a visible-light telescope, it would need to be ...

Much larger

If you wanted a radio telescope to achieve the same angular resolution as a visible-light telescope, it would need to be:

Much larger

Which of the following is not a major pattern of motion in the solar system?

Nearly all comets orbit the Sun in same direction and roughly the same plane

Which of the following is not a major pattern of motion in the solar system?

Nearly all comets orbit the Sun in same direction and roughly the same plane.

b

Nearly all the visible light we see from the Sun is emitted from the _____. a. radiation zone b. photosphere c. core d. corona

Using the ideas discussed in your textbook, in what sense are we "star stuff"?

Nearly every atom from which we are made was once inside of a star.

Could we see a galaxy that is 20 billion light-years away? (Assume that we mean a "lookback time" of 20 billion years.)

No, because it would be beyond the bounds of our observable universe.

Could we see a galaxy that is 50 billion light-years away?

No, because it would be beyond the bounds of our observable universe.

1,2,3,5

Now consider the second major feature (two types of planets). Which of the following statements are true for the terrestrial and jovian planets in our solar system? Select all that apply. 1. Jovian planets have more moons than terrestrial planets. 2. Jovian planets are larger in size than terrestrial planets. 3. Jovian planets orbit farther from the Sun than terrestrial planets. 4. Jovian planets are made most of metal, rock, and helium. 5. Jovian planets are larger in mass than terrestrial planets.

b

Nuclear fusion of hydrogen into helium occurs in the ___. a. convection zone b. core c. corona d. radiation zone

b

Nuclear power plants on Earth create energy in the same way as the Sun. a. True b. False

Figure showing a laboratory spectrum on the top and four object spectra underneath. Now consider Object 2. What can you say about Object 2 in comparison to Object 1? Object 1 had a higher temperature than Object 2. Object 2 contains more hydrogen than Object 1. Object 2 is moving away from us faster than Object 1. Object 2 is moving toward us while Object 1 is moving away from us.

Object 2 is moving away from us faster than Object 1. Object 2's lines are shifted farther to the right than Object 1's, which means it has a greater redshift and is moving away faster.

Consider two future observatories in space. Observatory X consists of a single 50-meter telescope. Observatory Y is an interferometer consisting of five 10-meter telescopes, spread out over a region 100 meters across. Which observatory can detect dimmer stars, and which one can see more detail in its images? (Assume all else is equal, such as quality of optics, types of instruments, and so on.

Observatory X can detect dimmer stars and Observatory Y reveals more detail in images.

d

On a cloudless day, what happens to most of the visible light headed toward Earth? a. It is reflected by Earth's atmosphere. b. It is absorbed and reemitted by gases in Earth's atmosphere. c. It is completely reflected by Earth's surface. d. It reaches Earth's surface, where some is reflected and some is absorbed.

Suppose that two stars are separated in the sky by 0.1 arcsecond. If you look at them with a telescope that has an angular resolution of 0.5 arcsecond, what will you see?

One point of light that is the blurred image of both stars.

How long does it take the Earth to complete one orbit around the Sun?

One year

Why are terrestrial planets denser than jovian planets?

Only dense materials could condense in the inner solar nebula.

According to our present theory of solar system formation, which of the following objects now reside quite far from the place where they formed originally?

Oort cloud comets

Radio telescopes would NOT represent a good choice for astronomical study of ________

Ordinary stars

a

Our modern theory of solar system formation—the nebular theory—successfully accounts for all the major features of our own solar system. However, when the first hot Jupiters were discovered, their existence seemed inconsistent with the nebular theory because this theory predicts that __________. a. jovian planets can form only in the cold, outer regions of a solar system b. any system with jovian planets should also have terrestrial planets c. jovian planets located close to their stars should have evaporated by now d. planetary systems should be extremely rare

Which of the following is not an advantage of spacecraft flybys over ground-based telescope observations?

Spacecraft can monitor changes in a planet's atmosphere over long times.

Which of the following is not a pattern of motion in our solar system?

Planets all rotate in the same direction.

What is the difference between energy and power?

Power is the rate at which energy is used, so its units are a unit of energy divided by a unit of time.

________ astronomy uses dishes like satellite dishes to observe objects. In some cases, the dishes work together to form images at a much higher resolution than any one of them could achieve alone. An example is Very Large Array in New Mexico. _________ telescopes are very similar to optical telescopes, except that they use different detectors to sense the light. An example is the Spitzer ___________Space Telescope. Most of the ___________ wavelengths act enough like the visible wavelengths that we can use the same sorts of telescopes, with different detectors. An example is the Hubble Space Telescope. _________ telescopes have to gently redirect the light because it tends to go straight through things in its path. Mirrors are arranged so that the light just grazes them. An example is the Chandra Space Telescope. ____________ telescopes must be massive in order to intercept this high-energy light. An example is the Fermi ______________ Telescope.

Radio, Infared, Infared, Uktraviolet,X-ray, Gamma-ray, Gamma-ray

How do scientists determine the age of the solar system?

Radiometric dating of meteorites

What is meant in astronomy by the phrase "adaptive optics"?

Rapid modifications are made to the tilt and location of the elements of a telescope to correct for the effects of atmospheric and instrumental distortion

The primary reason professional observatories are built on the highest mountaintops is to

Reduce atmospheric blurring

Listed following are distinguishing characteristics and examples of reflecting and refracting telescopes. Match these to the appropriate category. Reflecting Telescopes: Refracting Telescopes: The world's largest is 1-meter in diameter, most commonly used by professional astronomers today, very large telescopes become "top- heavy", The Hubble Space Telescope, world's largest telescope, incoming light passes through glass

Reflecting Telescopes: most commonly used by professional astronomers today, The Hubble Space Telescope, world's largest telescope Refracting Telescopes: The world's largest is 1-meter in diameter, Galileo's telescopes, very large telescopes become "top- heavy", incoming light passes through glass

Where is our solar system located within the Milky Way Galaxy?

Roughly halfway between the center and the edge of the visible disk of the galaxy

Suppose you built a scale-model atom in which the nucleus is the size of a tennis ball. About how far would the cloud of electrons extend?

Several kilometers

If you could count stars at a rate of about one per second, how long would it take to count all the stars in the Milky Way Galaxy?

Several thousand years

What is the primary reason that astronomers suspect that some jovian moons were captured into their current orbits?

Some moons have orbits that are "backwards" (compared to their planet's rotation) or highly inclined to their planet's equator.

Astronomical sources emit electromagnetic radiation at various wavelengths. Some sources might emit just visible and infrared radiation. Other sources might emit gamma, UV, visible, and infrared radiation. Some of that radiation travels in the direction of Earth and can be detected with the right telescopes placed in the right locations. Some wavelengths can be read in the atmosphere. However, the majority of wavelengths are either read from space or Earth's surface. Which observations would require you to launch a telescope above the Earth's atmosphere? Please drag each observing mode below into either the ground-based (Surface) zone or space-borne (Space) zone, depending on the respective observing requirements.

Space Zone: - Far-infrared observations - Gamma-ray observations - X-ray observations - Far-ultraviolet observations Surface Zone: - Visible observations - Radio observations

_____________ separate the various colors of light, allowing astronomers to determine stellar composition and many other stellar properties.

Spectrographs

Suppose that Star X and Star Y both have redshifts, but Star X has a larger redshift than Star Y. What can you conclude?

Star X is moving away from us faster than Star Y.

Suppose that Star X and Star Y both have redshifts, but Star X has a larger redshift than Star Y. What can you conclude? Star X is moving away from us faster than Star Y. Star X is coming toward us faster than Star Y. Star X is moving away from us and Star Y is moving toward us. Star Y is moving away from us faster than Star X. Star X is hotter than Star Y.

Star X is moving away from us faster than Star Y. The redshifts mean that both stars are moving away from us, and a larger redshift means a faster speed.

Which of the following is a general difference between a planet and a star?

Stars glow in infrared and visible light, while planets glow only in the infrared.

Which of the following best explains why we can rule out the idea that planets are usually formed by near-collisions between stars?

Stellar near-collisions are far too rare to explain all the planets now known to orbit nearby stars.

Which of the following studies is best suited to astronomical observations that fall into the category called time monitoring?

Studying how a star's brightness varies over a period of 3 years.

a

Sunsets are red because sunlight must pass through more atmosphere when the sun is low in the sky, and the atmosphere scatters even more of the shorter wavelengths, leaving mostly red light to color the sky. a. True b. False

The length of each season (for example, the number of days from the summer solstice to the fall equinox) would be significantly longer than it is now.

Suppose Earth's axis tilt was significantly greater than its current 23.5 degrees, but Earth's rotation period and orbital period were unchanged. Which statement below would not be true?

Which of the following conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space?

The cloud is cool and lies between you and a hot star.

new Earth

Suppose it is full Moon. What phase of Earth would someone on the Moon see at this time?

c

Suppose the Sun had been born with less mass, making it a small, cooler star only able to heat everything around it to a level one-half as hot as its current temperature. According to the solar nebular theory, how would the formation of the solar system have been dierent? a. There would be no comets. b. Asteroids would have formed farther from the Sun. c. Both terrestrial and jovian planets would have generally formed closer to the Sun. d. There would be no terrestrial planet systems.

To the right of Polaris; that is, 90 degrees counterclockwise from its current position

Suppose you are facing north and you see the Big Dipper close to your northern horizon, with Polaris (and the Little Dipper) above it. Where will you see the Big Dipper in six hours?

Your friend will also see a crescent moon.

Suppose you live in the United States and you see a crescent moon in your evening sky tonight. What will a friend in South America see tonight?

the Galileo spacecraft that orbited Jupiter in the 1990s

Suppose you see a photo showing Jupiter half in sunlight and half in shadow (that is, a first quarter Jupiter). This photo might have been taken by _________.

b

Suppose you start with 1 kilogram of a radioactive substance that has a half-life of 10 years. Which of the following statements will be true after 20 years pass? a. You'll have 0.5 kilogram of the radioactive substance remaining. b. You'll have 0.25 kilogram of the radioactive substance remaining. c. All the material will have completely decayed. d. You'll have 0.75 kilogram of the radioactive substance remaining.

latitude 40 degrees south

Suppose you use the Southern Cross to determine that the south celestial pole appears 40 degrees above your horizon. Then you must be located at _________.

Which of the following statements best describes the two principle advantages of telescopes over eyes?

Telescopes can collect far more light with far better angular resolution.

Which of the following is not a major difference between the terrestrial and jovian planets in our solar system?

Terrestrial planets contain large quantities of ice and jovian planets do not.

Which of the following is not a major difference between the terrestrial and jovian planets in our solar system?

Terrestrial planets contain large quantities of ice and jovian planets do not.

How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope? The 8-meter telescope has 8 times the light-collecting area of the 2-meter telescope. The answer cannot be determined from the information given in the question. The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope. The 8-meter telescope has 4 times the light-collecting area of the 2-meter telescope.

The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope. The 8-meter telescope is 4 times larger in diameter, so its light collecting area is 42 = 16 times greater.

We could not see it at all.

The Andromeda Galaxy is faintly visible to the naked eye in the constellation Andromeda. Suppose instead it were located in the same direction in space as the center of the Milky Way Galaxy (but still at its current distance). How would it appear to the eye in that case?

c

The Doppler method can be used to measure the orbital period of a planet by a. measuring the speed at which the star orbits the mutual center-of-mass of the star and planet. b. measuring the asymmetries in the velocity curve. c. measuring the time it takes for the star's line-of-sight velocity to cycle from peak to peak. d. measuring the amount by which the starlight is reduced when the planet transits.

d

The Doppler method of discovering extrasolar planets works best for a. high mass planets far from their host star. b. low mass planets close to their host star. c. planets that have been ejected from their systems. d. high mass planets close to their host star. e. low mass planets far from their host star.

Which of the following telescopes benefits most from adaptive optics?

The Keck I telescope on Mauna Kea

Consider the following statement: "Rocky asteroids are found primarily in the asteroid belt and Kuiper belt while icy comets are found primarily in the Oort cloud." What's wrong with this statement?

The Kuiper belt contains icy comets, not rocky asteroids

Consider the following statement: "Rocky asteroids are found primarily in the asteroid belt and Kuiper belt while icy comets are found primarily in the Oort cloud." What's wrong with this statement?

The Kuiper belt contains icy comets, not rocky asteroids.

Which of the following is not a line of evidence supporting the hypothesis that our Moon formed as a result of a giant impact?

The Pacific Ocean appears to be a large crater - probably the one made by the giant impact.

Which of the following statements is an inference from a model (rather than an observation)? The photosphere emits visible light. The photosphere is made out of mainly hydrogen and helium. The Sun's core is gradually turning hydrogen into helium. The Sun emits neutrinos. The corona is hotter than the photosphere.

The Sun's core is gradually turning hydrogen into helium.

What would happen if the fusion rate in the core of the Sun were increased but the core could not expand? The Sun's core would start to cool down and the rate of fusion would decrease. The Sun's core would reach a new equilibrium at a lower temperature. The Sun's core would reach a new equilibrium at a higher temperature. The Sun's core would start to heat up and the rate of fusion would increase even more.

The Sun's core would start to heat up and the rate of fusion would increase even more As you know from Part B, an increase in the fusion rate will cause the core to expand in a normal (or main-sequence) star like the Sun, and this expansion will restore core equilibrium. But if for some reason the core could not expand, the higher temperature would make the fusion rate increase even more, creating a positive feedback loop in which the fusion rate and temperature would keep getting higher and higher. (That is, there would be no equilibrium.) In fact, as you'll learn when you study stellar life cycles, this is essentially what will occur when the Sun is near the end of its life.

Which of the following statements about our Sun is not true?

The Sun's diameter is about 5 times that of Earth.

the spring and fall equinoxes

The Sun's path, as viewed from the equator, is highest in the sky on _________.

d

The ______ is the layer of the Sun between its core and convection zone. a. photosphere b. chromosphere c. corona d. radiation zone

What does angular resolution measure?

The angular size of the smallest features that the telescope can see

What does angular resolution measure?

The angular size of the smallest features that the telescope can see.

b

The asteroid belt lies between the orbits of a. Earth and Mars. b. Mars and Jupiter. c. Jupiter and Saturn.

Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. What is its atomic number and atomic mass number? The atomic number is 118, and the atomic mass number is 197. The atomic number is 79, and the atomic mass number is 197. The atomic number is 118, and the atomic mass number is 79. The atomic number is 79, and the atomic mass number is 118.

The atomic number is 79, and the atomic mass number is 197.

astronomical unit (au)

The average distance (semimajor axis) of Earth from the Sun, which is about 150 million km.

astronomical unit (AU)

The average distance between Earth and the Sun, which is about 150 million kilometers. More technically, 1 AU is the length of the semimajor axis of Earth's orbit.

When we say the universe is expanding, we mean that:

The average distance between galaxies is growing with time

Suppose you see two stars: a blue star and a red star. Which of the following can you conclude about the two stars? Assume that no Doppler shifts are involved. (Hint: Think about the laws of thermal radiation.) The blue star has a hotter surface temperature than the red star. The red star has a hotter surface temperature than the blue star. The blue star is more massive than the red star. The red star is more massive than the blue star. The blue star is farther away than the red star.

The blue star has a hotter surface temperature than the red star.

Which of the following conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space? The cloud is cool and very dense, so that you cannot see any objects that lie behind it. The cloud is cool and lies between you and a hot star. The cloud is extremely hot. The cloud is visible primarily because it reflects light from nearby stars.

The cloud is cool and lies between you and a hot star. Atoms or molecules in the cloud therefore absorb specific wavelengths of light from the hot star.

Which of the following statements about the asteroid belt is not true?

The combined mass of all the asteroids is roughly the same as the mass of Earth.

Which of the following statements about the asteroid belt is not true?

The combined mass of all the asteroids is roughly the same as the mass of the Earth.

Suppose you find a rock that contains 10 micrograms of radioactive potassium-40, which has a half-life of 1.25 billion years. By measuring the amount of its decay product (argon-40) present in the rock, you conclude that there must have been 80 micrograms of potassium-40 when the rock solidified. How old is the rock?

The current 10 micrograms of potassium-40 is 1/8 of the original 80 grams, which means the amount of potassium-40 has declined by a factor of 8. Therefore, three half-lives have passed (since 23 = 8) and the rock is 3x1.25 = 3.75 billion years old.

The visible spectrum of the Sun. This photo shows the visible light spectrum of the Sun. Why does it have all those dark lines on it? The dark lines are caused by Doppler shifts. The dark lines represent wavelengths of light at which atoms near the Sun's surface absorb radiation from the hotter solar interior. The dark lines are not real, but rather are artifacts of the photographic process used to record the spectrum. The dark lines come from sunspots on the Sun, which are dark in color.

The dark lines represent wavelengths of light at which atoms near the Sun's surface absorb radiation from the hotter solar interior. In other words, the Sun has an absorption line spectrum because its surface (photosphere) acts like a cooler cloud over the much hotter interior.

The following statements are all true. Which one counts as an "exception to the rule" in being unusual for our solar system?

The diameter of Earth's Moon is about 1/4 that of Earth.

The following statements are all true. Which one counts as an "exception to the rule" in being unusual for our solar system?

The diameter of Earth's Moon is about 1/4 that of Earth.

d

The discovery of hot Jupiters led scientists to reconsider the nebuar theory. Which of the following best explains why the nebular theory(as it stood before the discoveries of extrasolar planets) had not predicted the existence of hot Jupiters? a. Scientists had no evidence that other stars could have disks of gas in which planets could form around. b. The nebular theory was fundamentally flawed and was incorrect about how planets form. c. The nebular theory was designed to apply only to our solar system, so there was no reason to think it would apply to others. d. There are no hot Jupiters in our solar system.

light-year (ly)

The distance that light can travel in 1 year, which is 9.46 trillion km.

light-year

The distance that light can travel in 1 year, which is about 10 trillion kilometers (more precisely, 9.46 trillion km).

The diagram represents energy levels in a hydrogen atom. The labeled transitions (A through E) represent an electron moving between energy levels. Suppose that an electron in a hydrogen atom absorbs 10.2 eV of energy, so that it moves from level 1 to level 2. What typically happens next? The electron remains in level 2 until it absorbs an additional 10.2 eV of energy. The electron jumps to level 3 as soon as it absorbs any additional energy. The electron returns to level 1 by emitting an ultraviolet photon with 10.2 eV of energy. A different electron drops into level 1, since it is now unoccupied.

The electron returns to level 1 by emitting an ultraviolet photon with 10.2 eV of energy.

d

The energy that warms Earth's surface comes primarily in the form of __________. a. heat from Earth's interior b. infrared light from the Sun c. heat from the Sun d. visible light from the Sun e. ultraviolet light from the Sun

Suppose that two stars are identical in every way - for example, same distance, same mass, same temperature, same chemical composition, and same speed relative to Earth - except that one star rotates faster than the other. Spectroscopically, how could you tell the stars apart?

The faster rotating star has wider spectral lines than the slower rotating star.

Which moons are sometimes called the Galilean moons?

The four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto.

What is the primary reason why a Pluto flyby mission would be cheaper than a Pluto orbiter?

The fuel needed for an orbiter to slow down when it reaches Pluto adds a lot of weight to the spacecraft.

You observe a distant galaxy. You find that a spectral line of hydrogen that is shifted from its normal location in the visible part of the spectrum into the infrared part of the spectrum. What can you conclude?

The galaxy is moving away from you.

c

The graph above shows how a star's orbital speed varies with time due to the gravitational tug of an orbiting planet. These data were obtained by measuring ___________. a. the precise wavelengths of spectral lines in the spectrum of the orbiting planet b. the orbital period of the planet that is orbiting the star c. the precise wavelengths of spectral lines in the spectrum of the star d. the precise brightness of the star divided by the precise brightness of the planet

c

The greenhouse effect raises Earth's surface temperature (from what it would be otherwise) because the infrared light radiated by Earth's surface __________. a. travels directly out to space b. becomes permanently trapped by greenhouse gases c. is absorbed by greenhouse gases, slowing the escape of this energy to space

local group

The group of about 40 galaxies to which the Milky Way Galaxy belongs.

expansion (of the universe)

The increase in the average distance between galaxies as time progresses.

c

The jovian planets are thought to have formed as gravity drew hydrogen and helium gas around planetesimals made of __________. a. only rocks and metals b. only ices c. rocks, metals, and ices d. rocks, metals, ices, and hydrogen and helium gases

According to our present theory of solar system formation, which of the following statements about the growth of terrestrial and jovian planets is not true?

The jovian planets began from planetesimals made only of ice, while the terrestrial planets began from planetesimals made only of rock and metal.

superclusters

The largest known structures in the universe, consisting of many clusters of galaxies, groups of galaxies, and individual galaxies.

According to our theory of solar system formation, which law best explains why the solar nebula spun faster as it shrank in size?

The law of conservation of angular momentum

Many meteorites appear to have formed very early in the solar system's history. How do these meteorites support our theory about how the terrestrial planets formed?

The meteorites appearance and composition is just what we'd expect if metal and rock condensed and accreted as our theory suggests.

observable universe

The portion of the entire universe that can be seen from Earth, at least in principle. The observable universe is probably only a tiny portion of the entire universe.

Which statement about motion in the universe is not true?

The mysterious dark matter is the fastest-moving material in the universe.

big bang

The name given to the event thought to mark the birth of the universe.

c

The nebular theory also predicts that the cloud will flatten into a disk as it shrinks in size. Which of the following best explains why the collapsing cloud should form a disk? a. As a star forms near the cloud center, its wind blows away material that is not aligned with its equator, thereby leaving an equatorial disk of material. b. Gravity pulls more strongly on material along the rotation axis than perpendicular to it, bringing this material downward into a disk. c. Colliding cloud particles exchange angular momentum and, on average, end up with the rotation pattern for the cloud as a whole. d. All collapsing objects tend to flatten into a disk, regardless of their rotation.

c

The northern hemisphere of Mars has fewer craters than the southern hemisphere. This indicates that a. the northern hemisphere did not experience as many impacts. b. oceans of water once covered the southern hemisphere. c. geologic processes have resurfaced much of the northern hemisphere. d.volcanoes were more common in the southern hemisphere.

Put the following into perspective: the size of our solar system; the distance to nearby stars; the size of the Milky Way Galaxy; the size of the observable universe. Rank from largest to smallest. To rank items as equivalent, overlap them.

The observable universe, The Milky Way Galaxy, Distances to nearby stars, solar system

orbit (or revolution)

The orbital motion of one object around another due to gravity. For example, Earth orbits the Sun once each year.

revolution

The orbital motion of one object around another.

c

The overall result of the proton-proton chain is that __________. a. 6 H becomes 1 He + energy b. individual protons are joined into long chains of protons c. 4 H becomes 1 He + energy d. p + p becomes 2H + energy

Which of the following best describes why we say that light is an electromagnetic wave?

The passage of a light wave can cause electrically charged particles to move up and down.

observable universe

The portion of the entire universe that, at least in principle, can be seen from Earth.

Which of the following best describes why we say that light is an electromagnetic wave? Which of the following best describes why we say that light is an electromagnetic wave? Light is produced only when massive fields of electric and magnetic energy collide with one another. The term electromagnetic wave arose for historical reasons, but we now know that light has nothing to do with either electricity or magnetism. Light can be produced only by electric or magnetic appliances. The passage of a light wave can cause electrically charged particles to move up and down.

The passage of a light wave can cause electrically charged particles to move up and down.

orbit

The path followed by a celestial body because of gravity; an orbit may be bound (elliptical) or unbound (parabolic or hyperbolic).

The angular separation of two stars is 0.1 arcseconds and you photograph them with a telescope that has an angular resolution of 1 arcsecond. What will you see? The photo will seem to show only one star rather than two. The stars will not show up at all in your photograph. The two stars will appear to be touching, looking rather like a small dumbbell. You will see two distinct stars in your photograph

The photo will seem to show only one star rather than two. Because the angular separation of the stars is smaller than the telescope's angular resolution, the light of the two stars will be blurred together to look like a single star.

What is the ecliptic plane?

The plane of Earth's orbit around the Sun

ecliptic plane

The plane of Earth's orbit around the Sun.

If we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet?

The planet is rotating.

If we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet? The planet is actually two bodies, one moving toward us, the other away from us. The planet is in the process of falling apart. The planet is in the process of formation. The planet is rotating.

The planet is rotating.

Suppose we make a scale model of our solar system, with the Sun the size of a grapefruit. Which of the following best describes what the planets would look like?

The planets are all much smaller than the Sun. Four planets are within about 20 meters of the Sun, while the rest planets are spread much farther apart.

a

The proton-proton chain converts four hydrogen nuclei into one helium nucleus plus energy. a. True b. False

Suppose you are listening to a radio station that broadcasts at a frequency of 97 Mhz (megahertz). Which of the following statements is true?

The radio waves from the radio station are causing electrons in your radio's antenna to move up and down 97 million times each second.

An image showing two stars. An image showing one star. The first telescopic photo shows what appears to be a single star. The second photo shows the same object, now revealed to be two distinct stars. What is the difference between the two photos? The second photo was taken by two telescopes rather than one. The second photo was taken with a telescope that has greater light-collecting area. The second photo has better (smaller) angular resolution than the first photo. The second photo comes from a radio telescope while the first photo comes from a visible-light photo.

The second photo has better (smaller) angular resolution than the first photo. Better angular resolution means we can see (resolve) the two individual sources that are blurred together in the first photo.

1,4,6

The solar system contains vast numbers of small bodies, which we call asteroids when they are rocky and comets when they are icy. These small bodies are concentrated in the region(s) of the solar system that we call __________. Select all that apply. 1. the Oort cloud 2. the Doppler belt 3. the solar corona 4. the asteroid belt 5. the comet belt 6. the Kuiper belt

d

The solar system has two types of planets, terrestrial and jovian. According to the nebular theory, why did terrestrial planets form in the inner solar system and jovian planets in the outer solar system? a. All the planets started out large, but the Sun's heat evaporated so much material that the inner planets ended up much smaller. b. Denser particles of rock and metal sank into the inner solar system, leaving only gases in the outer solar system. c. After the planets formed, the Sun's gravity pulled the dense terrestrial planets inward, leaving only jovian planets in the outer solar system. d. Ices condensed only in the outer solar system, where some icy planetesimals grew large enough to attract gas from the nebula, while only metal and rock condensed in the inner solar system, making terrestrial planets.

c

The source of energy that keeps the Sun shining today is _________. a. gravitational contraction b. nuclear fission c. nuclear fusion d. chemical reactions (fire)

rotation

The spinning of an object around its axis.

rotation

The spinning of an object around its axis. For example, Earth rotates once each day around its axis, which is an imaginary line connecting the North and South Poles.

Laboratory measurements show hydrogen produces a spectral line at a wavelength of 486.1 nanometers (nm). A particular star's spectrum shows the same hydrogen line at a wavelength of 486.0 nm. What can we conclude?

The star is moving toward us.

Laboratory measurements show hydrogen produces a spectral line at a wavelength of 486.1 nanometers (nm). A particular star's spectrum shows the same hydrogen line at a wavelength of 486.0 nm. What can we conclude? The star is moving away from us. The star is moving toward us. The star is getting hotter. The star is getting colder.

The star is moving toward us. The wavelength is shifted from 486.1 to 486.0 nm, which means a shift to a shorter wavelength. A shorter wavelength means a shift to the blue end of the spectrum (a blueshift) so that the object is moving toward us.

Which of the following best describes what we mean by the universe?

The sum total of all matter and energy

universe

The sum total of all matter and energy.

universe (or cosmos)

The sum total of all matter and energy—that is, all galaxies and everything between them.

d

The transit method of planet detection works best for a. small planets in edge-on orbits around big stars. b. Earth-like planets in any orbit. c. small planets in face-on orbits around big stars. d. big planets in edge-on orbits around small stars. e. big planets in face-on orbits around small stars.

All of the following statements about the Sun's corona are true. Which one explains why it is a source of X rays?

The temperature of the corona's gas is some 1 to 2 million Kelvin.

What is the primary basis upon which we divide the ingredients of the solar nebula into four categories (hydrogen/helium; hydrogen compound; rock; metal)?

The temperatures at which various materials will condense from gaseous form to solid form.

c

The terrestrial planets are made almost entirely of elements heavier than hydrogen and helium. According to modern science, where did the elements heavier than hydrogen and helium come from? a. They were produced by gravity in the solar nebula as it collapsed. b. They have been present in the universe since its birth. c. They were produced by stars that lived and died before our solar system was born. d. They were made by chemical reactions in interstellar gas.

Which of the following is not a reason why telescopes tend to be built on mountaintops that are relatively far from cities and are in regions with dry climates?

The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.

Studying a spectrum from a star can tell us a lot. All of the following statements are true except one. Which statement is not true?

The total amount of light in the spectrum tells us the star's radius.

Studying a spectrum from a star can tell us a lot. All of the following statements are true except one. Which statement is not true? We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals. The total amount of light in the spectrum tells us the star's radius. Shifts in the wavelengths of spectral lines compared to the wavelengths of those same lines measured in a laboratory on Earth can tell us the star's speed toward or away from us. The peak of the star's thermal emission tells us its temperature: hotter stars peak at shorter (bluer) wavelengths.

The total amount of light in the spectrum tells us the star's radius. We cannot measure radius from a spectrum without additional information.

The planet Neptune is blue in color. How would you expect the spectrum of visible light from Neptune to be different from the visible-light spectrum of the Sun?

The two spectra would have similar shapes, except Neptune's spectrum would be missing a big chunk of the red light that is present in the Sun's spectrum.

The fact that nearly all galaxies are moving away from us, with more distant ones moving faster, helped us to conclude that:

The universe is expanding

According to our present theory of solar system formation, how did Earth end up with enough water to make oceans?

The water was brought to the forming Earth by planetesimals that accreted beyond the orbit of Mars.

Which of the following observations indicates that conditions on Mars may have been suitable for life in the past?

There are dried-up riverbeds on Mars.

About 2% of our solar nebula consisted of elements besides hydrogen and helium. However, the very first generation of star systems in the universe probably consisted only of hydrogen and helium. Which of the following statements is most likely to have been true about these first-generation star systems?

There were no comets or asteroids in these first-generation star systems.

The region of our solar system between Mercury and Mars has very few asteroids, while the region between Mars and Jupiter has many asteroids. Based on what you have learned, what is the most likely explanation for the lack of asteroids between Mercury and Mars?

There were very few planetary leftovers in this region, because most of the solid material was accreted by the terrestrial planets as the planets formed.

Which of the following is not a characteristic of the inner planets?

They all have substantial atmospheres.

Which of the following is always true about images captured with X-ray telescopes?

They are always shown with colors that are not the true colors of the objects that were photographed.

Which of the following is always true about images captured with X-ray telescopes? They are always very pretty. They always are made with adaptive optics. They show us light with extremely long wavelengths compared to the wavelengths of visible light. They always have very high angular resolution. They are always shown with colors that are not the true colors of the objects that were photographed.

They are always shown with colors that are not the true colors of the objects that were photographed. "True colors" make sense only for visible light, not X rays.

Suppose you watch a leaf bobbing up and down as ripples pass it by in a pond. You notice that it does two full up and down bobs each second. Which statement is true of the ripples on the pond? They have a frequency of 2 hertz. They have a frequency of 4 hertz. They have a wavelength of two cycles per second. We can calculate the wavelength of the ripples from their frequency.

They have a frequency of 2 hertz - Remember that hertz are units meaning "cycles per second."

Suppose you watch a leaf bobbing up and down as ripples pass it by in a pond. You notice that it does two full up and down bobs each second. Which statement is true of the ripples on the pond?

They have a frequency of 2 hertz.

Which of the following best describes the fundamental difference between two different chemical elements (such as oxygen and carbon)?

They have different numbers of protons in their nucleus.

Which of the following is not a characteristic of the outer planets?

They have very few, if any, satellites.

c

Today, the leading hypothesis for the existence of hot Jupiters is that they formed in their outer solar systems and then migrated inward. Why did this hypothesis gain favor over alternative ideas? a. Scientists did not find any reason to favor any of the alternate explanations, so by process of elimination they settled on the migration hypothesis. b. The migration hypothesis requires the least modification to the nebular theory and therefore was preferred over any alternatives. c. Computer models that simulate planetary formation show that interactions between young planets and other material in the surrounding disk can cause planetary migration. d. Telescopic observations have revealed several star systems in which planets can be seen migrating rapidly inward.

a

Two stars with about the same mass are found to have transiting planets with similar semi-major axes. Star 1 exhibits a Doppler shift twice as large as Star 2. What can we determine about these two systems? a. The planet around Star 1 is more massive than the planet around Star 2. b. The planet around Star 1 has a thicker atmosphere than the planet around Star 2. c. The planet around Star 2 is more massive than the planet around Star 1. d. The planet around Star 2 has a thicker atmosphere than the planet around Star 1.

Which of the following wavelength regions cannot be studied with telescopes on the ground?

Ultraviolet, X-rays

What is the Kuiper belt?

a region of the solar system beginning just beyond the orbit of Neptune that contains many icy comets

Suppose you decide to make a graph of intensity against wavelength for the spectrum shown here. Which of the following shows what the graph will look like?

Upside down spike wavelength graph Notice that the downward spikes on the graph occur at wavelengths corresponding to the dark lines in the spectrum.

Which planet listed below has the most extreme seasons?

Uranus

milky way

Used both as the name of our galaxy and to refer to the band of light we see in the sky when we look into the plane of our galaxy.

a

Venus has a thicker atmosphere than Earth. a. True b. False

Which planet has the highest average surface temperature, and why?

Venus, because of its dense carbon dioxide atmosphere

The planet closest in size to Earth is

Venus.

The planet in our solar system with the highest average surface temperature is

Venus.

landed on mars in 1976

Viking 1,2

Which of the following forms of light can be observed with telescopes at sea level?

Visible light Radio waves

c

We can see the Sun's _____ most easily during total solar eclipses. a. core b. photosphere c. corona d. radiation zone

Which of the following statements about Mars is not true?

We could survive on Mars without spacesuits, as long as we brought oxygen in scuba tanks.

b

What do we mean by the frost line when we discuss the formation of planets in the solar nebula? a. It marks the special distance from the Sun at which hydrogen compounds become abundant; closer to the Sun, there are no hydrogen compounds. b. It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ice to condense. c. It is the altitude in a planet's atmosphere at which snow can form. d. It is another way of stating the temperature at which water freezes into ice.

a

What happens to the energy that the ground absorbs in the form of visible sunlight? a. It is returned upward in the form of infrared light. b. It is returned upward in the form of visible light. c. It makes the ground continually get hotter and hotter.

c

What is the chief difficulty in attempting to detect planets around other stars? a. As viewed from Earth, planets often hide behind their stars and cannot be seen. b. Even the largest planets are thousands of times smaller than their host stars. c. Planets do not emit visible light, and they are typically at least a billion times fainter than their host stars. d. Planets do not glow in the infrared, so infrared telescopes cannot be used to study them, either. e. all of the above

d

What is the giant impact hypothesis for the origin of the Moon? a. The Moon formed when two gigantic asteroids collided with one another. b. The Moon originally was about the same size as Earth, but a giant impact blasted most of it away so that it ended up much smaller than Earth. c. The Moon formed just like the Earth, from accretion in the solar nebula. d. The Moon formed from material blasted out of the Earth's mantle and crust by the impact of a Mars-size object.

d

What is the importance of the carbon dioxide (CO2) cycle? a. It allows for an ultraviolet-absorbing stratosphere. b. It makes the growth of continents possible. c. It will prevent us from suffering any consequences from global warming. d.It regulates the carbon dioxide concentration of our atmosphere, keeping temperatures moderate.

a

What is the main reason that Mars, compared to Earth, has become so geologically inactive? a. its size b. its rotation rate c. its tilt d. its composition e. its distance from the Sun

d

What is the transit method of finding extrasolar planets? a. observing a star during the rare occasion of another star passing directly in front of it; slight changes in how the light is bent by gravity can indicate the presence of planets around the closer star b. monitoring a star to detect periodic dips in its brightness from the planet passing behind the star c. measuring the spectrum of the star for a periodic variation in its Doppler shift d. monitoring a star to detect periodic dips in its brightness from the planet passing in front of the star

d

What keeps the Sun's outer layers from continuing to fall inward in a gravitational collapse? a. electromagnetic repulsion between protons b. neutrinos produced by nuclear fusion drag gas outward c. the strong force between protons d. outward pressure due to super-heated gas

a

What key process underlies why Mars changed so much from its early conditions to its conditions today? a. Interior cooling. b. Evaporation of its ocean. c. Outgassing. d. Slowing of its rotation rate.

a

What kind of material in the solar nebula could condense at temperatures as high as 1,500 K, such as existed in the inner region of the nebula? a. metals b. rocks c. hydrogen compounds d. silicon-based minerals e. molecules such as methane and ammonia

b

What must be true about the orbit of a planet discovered by the transit method? a. The planet's orbit must be very close to circular. b. As seen from Earth, the planet's orbit must be nearly parallel to our line of sight. c. The planet's orbit must be very eccentric. d. As seen from Earth, the planet's orbit must be nearly perpendicular to our line of sight. e. The planet must be closer to its star than Mercury is to the Sun.

e

What percentage of the solar nebula's mass consisted of hydrogen and helium gases? a. 0.5 percent b. 50 percent c. 5 percent d. 100 percent e. 98 percent

a

What substances existed as solid flakes within the innermost regions (within about the inner 0.3 AU) of the solar system before planets began to form? a. none b. only rocks and metals c. only hydrogen compounds d. only hydrogen and helium gases

e

What substances were found in the innermost regions (within about the inner 0.3 AU) of the solar system before planets began to form? a. nothing at all b. only rocks and metals c. only hydrogen compounds d. only hydrogen and helium gases e. rocks, metals, hydrogen compounds, hydrogen, and helium, all in gaseous form

d

What two physical processes balance each other to create the condition known as gravitational equilibrium in stars? a. the strong force and the electromagnetic force b. the strong force and the weak force c. gravitational force and surface tension d. gravitational force and outward pressure

d

What would happen if the fusion rate in the core of the Sun were increased but the core could not expand? a. The Sun's core would start to cool down, and the rate of fusion would decrease. b. The Sun's core would reach a new equilibrium at a lower temperature. c. The Sun's core would reach a new equilibrium at a higher temperature. d. The Sun's core would start to heat up, and the rate of fusion would increase even more.

c

What's the best explanation for the location of hot Jupiters? a. The strong gravity of their stars pulled them in close. b. They formed closer to their stars than Jupiter did. c. They formed farther out like Jupiter but then migrated inward.

b

Which of the following is not a major difference between the terrestrial and jovian planets in our solar system? a. Jovian planets have rings, and terrestrial planets do not. b. Terrestrial planets contain large quantities of ice, and jovian planets do not. c. Terrestrial planets are higher in average density than jovian planets. d. Terrestrial planets orbit much closer to the Sun than jovian planets.

Which of the following correctly describes how the process of gravitational contraction can make a star hot? Gravitational contraction involves the generation of heat by chemical reactions, much like the burning of coal. When a star contracts in size, gravitational potential energy is converted to thermal energy. Gravitational contraction involves nuclear fusion, which generates a lot of heat. Heat is generated when gravity contracts, because gravity is an inverse square law force.

When a star contracts in size, gravitational potential energy is converted to thermal energy.

higher in the sky

When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting _________.

Which of the following statements about X rays and radio waves is not true? X rays travel through space faster than radio waves. X rays have higher frequency than radio waves. X rays and radio waves are both forms of light, or electromagnetic radiation. X rays have shorter wavelengths than radio waves.

X rays travel through space faster than radio waves.

b

Where would you expect terrestrial planets to form in the solar nebula? a. within the innermost regions (within about the inner 0.3 AU) b. anywhere between the innermost regions (within about the inner 0.3 AU) and the frost line c. anywhere outside the innermost regions (within about the inner 0.3 AU) d. anywhere outside the frost line

a

Which extrasolar planet has the smallest Doppler shift? a. a planet 2.5 AU away from its star b. a planet 1.5 AU away from its star c. a planet 2.0 AU away from its star d. a planet 1.0 AU away from its star

b

Which is not a characteristic of asteroids? a. compositions similar to that of the terrestrial planets b. normally found in Kuiper belt or Oort cloud c. typically orbit the Sun at approximately 3 AU

b

Which is not a characteristic of comets? a. most are located in either the Kuiper belt or Oort cloud. b. dust particles entering Earth's atmosphere at a high speed c. visible in the sky as a fuzzy patch of light that rises and sets with the stars d. form a coma when near the sun

c

Which is not a characteristic of meteors? a. visible in the sky as a bright streak of light for only a few seconds. b. dust particles entering Earth's atmosphere at high speed. c. typically orbit the Sun at approximately 3 AU.

a

Which of the following best explain what we think happened to outgassed water vapor on Venus? a. Ultraviolet light split the water molecules, and the hydrogen then escaped to space. b. Water was removed from the atmosphere by chemical reactions with surface rock. c. It turned into carbon dioxide by reacting with nitrogen in Venus's atmosphere. d. It is frozen as water ice in craters near the poles.

1,4

Which of the following changes would cause the fusion rate in the Sun's core to increase? Check all that apply. 1. an increase in the core temperature 2. an increase in the core radius 3. a decrease in the core temperature 4. a decrease in the core radius

c

Which of the following is not evidence supporting the idea that our Moon formed as a result of a giant impact? a. Computer simulations show that the Moon could really have formed in this way. b. The Moon has a much smaller proportion of easily vaporized materials than Earth. c. The Pacific Ocean appears to be a large crater-probably the one made by the giant impact. d. The Moon's average density suggests it is made of rock much more like that of the Earth's outer layers than that of the Earth as a whole.

2,3

Which of the following must occur for a star's core to reach equilibrium after an initial change in fusion rate? Check all that apply. 1. If the fusion rate initially decreases, then the core expands. 2. If the fusion rate initially increases, then the core expands. 3. If the fusion rate initially decreases, then the core contracts. 4. If the fusion rate initially increases, then the core contracts.

a

Which of the following properties can be inferred from the star's orbital period? a. the planet's orbital radius b. the planet's mass c. both the planet's orbital radius and its mass d. neither the planet's orbital radius nor its mass

b

Which of the following show evidence of ancient river beds? a. Venus b. Mars c. the Moon d. Mercury e. all of the above

The "celestial sphere" is another name for our universe.

Which of the following statements about the celestial sphere is NOT true?

c

Which one has the strongest gravitational force exerted by an extrasolar planet on its central star? a. a planet with one Jupiter mass with an orbital period 2 AU away from its star b. a planet with four Jupiter masses with an orbital period 4 AU away from its star c. a planet with two Jupiter masses 1 AU away from its star

e

Which one of the following is not one of the four major features of the solar system? a. Planets fall into two major categories (terrestrial and jovian). b. Large bodies in the solar system have orderly motions. c. Several exceptions to the general trends stand out. d. Swarms of asteroids and comets populate the solar system. e. The solar system contains eight planets plus dwarf planets (such as Ceres, Pluto, and Eris).

c

Why are planets with long orbital periods among the last to be discovered? a. They will never block any of the light from their host star. b. Very few of these planets exist. c. Astronomers have to watch a long time before they repeat their orbits. d. They are harder to see against the bright light of the host star.

c

Why did the solar nebula heat up as it collapsed? a. Radiation from other nearby stars that had formed earlier heated the nebula. b. Nuclear fusion occurring in the core of the protosun produced energy that heated the nebula. c. As the cloud shrank, its gravitational potential energy was converted to thermal energy. d. The shock wave from a nearby supernova heated the gas. e. As the cloud shrank, its kinetic energy was converted to gravitational potential energy.

d

Why didn't a planet form where the asteroid belt is now located? a. There was not enough material in this part of the solar nebula to form a planet. b. There was too much rocky material to form a terrestrial planet, but not enough gaseous material to form a jovian planet. c. The temperature in this portion of the solar nebula was just right to prevent rock from sticking together. d. Gravitational tugs from Jupiter prevented material from collecting together to form a planet.

b

Why does Venus have such a large difference in temperature between its "no atmosphere" temperature and its actual temperature? a. It is so close to the Sun. b. It has a large amount of carbon dioxide in its atmosphere. c. It has a slow rotation. d. It has a high level of volcanic activity.

When did humans learn that the Earth is not the center of the universe?

Within the past 500 years

a

Without greenhouse gases, water on Earth's surface would be completely frozen. a. True b. False

Why can't X-ray and gamma-ray telescopes use the same designs as visible-light telescopes?

X rays and gamma rays have so much energy that they cannot be reflected in the same way as visible light.

The Chandra X-ray Observatory must operate in space because:

X rays do not penetrate Earth's atmosphere.

The Chandra X-ray Observatory must operate in space because: X rays do not penetrate Earth's atmosphere. X-ray telescopes require the use of grazing incidence mirrors. It was built by NASA. X rays are too dangerous to be allowed on the ground.

X rays do not penetrate Earth's atmosphere. To detect X rays, the observatory must be above Earth's atmosphere.

Which of the following statements about X rays and radio waves is not true?

X rays travel through space faster than radio waves.

Shown following are six different types of light that travel to Earth from sources in space. Rank these types of light from left to right based on the altitude in the atmosphere where they are completely absorbed, from highest to lowest (Earth's surface). If two (or more) of the choices reach the same altitude or the surface, rank them as equal by dragging one on top of the other(s).

X-rays, most ultraviolet, most infared light, stacked on each other =most radio waves, green visible light

A full moon high in the sky

You observe a full Moon rising at sunset. What will you see at midnight?

Which of the following has your "cosmic address" in the correct order?

You, Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe

Visible light from a distant star can be spread into a spectrum by using a glass prism or ______.

a diffraction grating

The number of stars in the Milky Way Galaxy is approximately _________.

a few hundred billion

No object produces a perfect thermal radiation spectrum, but many objects produce close approximations. Which of the following would not produce a close approximation to a thermal radiation spectrum?

a hot, thin (low-density, nearly transparent) gas

The spacecraft called Curiosity is _____.

a rover on Mars

According to the laws of thermal radiation, hotter objects emit photons with _________.

a shorter average wavelength

What is the angular resolution of the human eye?

about 1 arcminute, or 1/60 of a degree

A light-year is _________.

about 10 trillion kilometers

This Figure showing blackbody curves for several stars and a human. This figure shows idealized thermal radiation spectra from several stars and a human. Based on this graph, at about what wavelength does a 15,000 K star emit its most intense light? about 20 nanometers about 100 nanometers About 100,000 nanometers about 1,000 nanometers

about 100 nanometers The blue curve represents the 15,000 K star and it peaks close to 102 = 100 nm on the wavelength axis.

The Hubble Space Telescope obtains higher-resolution images than most ground-based telescopes because it is: larger. closer to the stars. above Earth's atmosphere.

above Earth's atmosphere.

The Hubble Space Telescope obtains higher-resolution images than most ground-based telescopes because it is:

above the Earth's atmophere

If we say that a material is opaque to ultraviolet light, we mean that it _________.

absorbs ultraviolet light

Consider a raisin cake expanding uniformly in an oven. Viewed from one of the raisins, you would see _____.

all other raisins moving away from you, with more distant raisins moving faster

Interferometry uses two or more telescopes to achieve:

an angular resolution equivalent to that of a much larger telescope.

If you heat a gas so that collisions are continually bumping electrons to higher energy levels, when the electrons fall back to lower energy levels the gas produces an emission line spectrum. radio waves. thermal radiation. X-rays. an absorption line spectrum.

an emission line spectrum.

The Cassini mission to Saturn consists of

an orbiter that orbits Saturn and a probe that descended to the surface of Titan.

When we look at an object that is 1,000 light-years away we see it _

as it was 1,000 years ago

When we look at an object that is 1,000 light-years away we see it _________.

as it was 1,000 years ago

Astronomers infer that the universe is expanding because distant galaxies all appear to

be moving away from us, with more distant ones moving faster

Astronomers infer that the universe is expanding because distant galaxies all appear to _________.

be moving away from us, with more distant ones moving faster

Venus has a higher average surface temperature than Mercury. Why?

because its surface is heated by an extreme greenhouse effect

Where are most of the known asteroids found?

between the orbits of Mars and Jupiter

What causes stars to twinkle?

bending of light rays by turbulent layers in the atmosphere

carried a probe that landed on Titan

cassini

Energy moves through the sun's _____ by means of the rising of hot gas and falling of cooler gas.

convection zone

Nuclear fusion of hydrogen into helium occurs in the _____.

core

we can see the sun's ______ most easily during total solar eclipses

corona

used a sky crane to lower itself to the surface of Mars

curiosity

If our eyes were sensitive only to X rays, the world would appear __________. If our eyes were sensitive only to X rays, the world would appear __________. gray, black, and white like a medical X ray brighter than normal because X rays carry more energy than visible light photons dark because X-ray light does not reach Earth's surface green, yellow, and orange, because those are the colors of X rays

dark because X-ray light does not reach Earth's surface Because X rays from the Sun do not reach Earth's surface, eyes that were sensitive only to X rays would have nothing to see.

The Earth rotates one a _ on its acis and orbits the Sun once each _ The eliptic plane is the plane defines by _ 's orbit around _. Axis tolt of a planet is the amount that _ is tipped relative to a line perpendicular to the ecliptic plane.

day, year, Earth, the Sun, its axis

Hubble Space Telescope

earth orbiter

voyager 2

flyby

How do we know how old the Sun is? from Newton's version of Kepler's third law and the orbits of the planets from its speed and distance from us from ages of solar system meteorites, based on radioactive elements from calculating its fuel supply and how fast it is using it up

from ages of solar system meteorites, based on radioactive elements

From shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation?

gamma rays, X rays, ultraviolet, visible light, infrared, radio

What two physical processes balance each other to create the condition known as gravitational equilibrium in stars? the strong force and the electromagnetic force gravitational force and surface tension gravitational force and outward pressure the strong force and the weak force

gravitational force and outward pressure

In which case will the woman see a just a spectrum that is almost entirely black except for few bright emission lines?

hot, glowing cloud of hydrogen gas The hot cloud emits light only at specific wavelengths, producing an emission line spectrum.

The spectra of most galaxies show redshifts. This means that their spectral lines _________.

have wavelengths that are longer than normal

Suppose you want to determine the chemical composition of a distant planet or star. Which of the following will be most useful to have?

high spectral resolution

What are the main constituents of the jovian planets?

hydrogen and helium

Where does nuclear fusion occur in the Sun?

in its core

If you had only one telescope and wanted to take both visible-light and ultraviolet pictures of stars, where should you locate your telescope? on Earth's surface on a tall mountain in an airplane in space

in space While visible light can be observed from the ground, ultraviolet light can be easily observed only from space. Indeed, the capability of observing ultraviolet light is a major advantage of the Hubble Space Telescope over larger ground-based telescopes.

The Chandra X-ray observatory focuses x-rays with ___________ mirrors. grazing

incidence

Listed following are distinguishing characteristics and examples of reflecting and refracting telescopes. Match these to the appropriate category. Refracting telescopes

incoming light passes through the glass, very large telescope becomes top heavy, the worlds largest is 1 meter in diameter, galileos telescope

The twin 10-m Keck telescopes can work together to obtain better angular resolution through a technique known as ________.

interferometry

An atom that has fewer electrons than protons is called a/an _________.

ion

A television advertisement claiming that a product is light-years ahead of its time does not make sense because

it uses "light-years" to talk about time, but a light-year is a unit of distance

Suppose you know the frequency of a photon and the speed of light. What else can you determine about the photon?

its wavelength and energy

Curiosity

lander

mapped most of the surface of Venus with radar observations from Venusian orbit

magellan

Sublimation is the process in which ___________.

molecules go directly from the solid phase to the gas phase

A gas heated to millions of degrees would emit mostly radio waves. an equal amount of all wavelengths of light. mostly X-rays. mostly ultraviolet light. no light, because it is too hot.

mostly X-rays.

Compared to the distance between Earth and Mars, the distance between Jupiter and Saturn is ______.

much larger

Compared to the distance between Earth and Mars, the distance between Jupiter and Saturn is

much larger.

is soon to become the first spacecraft to fly by Pluto

new horizon

The source of energy that keeps the Sun shining today is _________. chemical reactions (fire) nuclear fission gravitational contraction nuclear fusion

nuclear fusion

the main part of the Galileo spacecraft (i.e., not its atmospheric probe)

planetary orbiter

Assume the woman in the figure uses her prism to look at a spectrum of light coming from the object(s) shown. In which case will she see a continuous rainbow of thermal radiation?

prism to hot light source A hot light source produces a continuous spectrum (of thermal radiation)

Thermal radiation is defined as _________.

radiation with a spectrum whose shape depends only on the temperature of the emitting object

The ______ is the layer of the Sun between its core and convection zone

radiation zone

In what part of the electromagnetic spectrum do the biggest telescopes on Earth operate?

radio

In what wavelength range was interferometry first routinely used?

radio

The Very Large Array. What kinds of light are these telescopes designed to detect? radio waves X rays ultraviolet light infrared and visible light light with extremely short wavelengths

radio waves This is the Very Large Array in New Mexico; the many radio telescopes are used together for interferometry.

Which of the following wavelength regions can be studied with telescopes on the ground?

radio, visible, and very limited portions of the infrared and ultraviolet regions

The large research observations on Mauna Kea use giant __________.

reflecting telescopes

Without telescopes or other aid, we can look up and see the Moon in the night sky because it glows through radioactive decay. reflects visible light. emits thermal radiation. emits visible light. reflects infrared light.

reflects visible light.

Galileo's telescope designs using lenses were examples of ____________.

refracting telescopes

When your eye forms an image, the _____ plays a role analogous to the detector in a camera.

retina

star system

see solar system.

Which of the following best describes Pluto in terms of the general characteristics of terrestrial and jovian planets?

size and solid surface similar to terrestrial planets; distance similar to jovian planets

Mars has two moons that are most similar in character to:

small asteroids

Mars has two moons that are most similar in character to

small asteroids.

On a scale in which the distance from Earth to the Sun is about 15 meters, the distance from Earth to the Moon is _________.

small enough to fit within your hand

Which of the following studies is best suited to a time monitoring experiment?

studying whether a particular star's brightness is steady or variable

What is the "Raisin Cake model" intended to explain?

that every raisin in a raisin cake moves farther away from every other raisin: there is no special central raisin (and no special central galaxy)

The term observable universe refers to

that portion of the universe that we can see in principle, given the current age of the universe

The term observable universe refers to _________.

that portion of the universe that we can see in principle, given the current age of the universe

Astronomers have decided that, rather than being a planet, Pluto is really just a large member of

the Kuiper belt.

Our solar system consists of _________.

the Sun and all the objects that orbit it

Einstein's famous equation, E=mc 2, explains the fact that __________.

the Sun generates energy to shine by losing some 4 million tons of mass each second

An astronomical unit (AU) is _________.

the average distance between Earth and the Sun

What do astronomers mean by the Big Bang?

the event that marked the beginning of the expansion of the universe

Which moons are sometimes called the Galilean moons?

the four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto

The total number of stars in the observable universe is roughly equivalent to

the number of grains of sand on all the beaches on Earth.

If we represent the solar system on a scale that allows us to walk from the Sun to Pluto in a few minutes, then:

the planets would all be marble size or smaller and the nearest stars would be thousands of miles away.

Which of the following could not be measured by an observation that uses only imaging?

the rate at which a variable star brightens and dims

Which of the following is not an exception to the general patterns in the solar system?

the rings of Saturn

The total number of stars in the observable universe is about

the same as the number of grains of sand on all the beaches on Earth

The total number of stars in the observable universe is about _________.

the same as the number of grains of sand on all the beaches on Earth

Which of the following could not be determined by an observation that uses only spectroscopy?

the size of a distant galaxy

What is aerobraking?

the technique of using a planetary atmosphere to change the orbit of a spacecraft

Our solar system consists of

the sun and all the objects that orbit it

Suppose you want to know the chemical composition of a distant star. Which piece of information is most useful to you?

the wavelengths of spectral lines in the star's spectrum

Which of the following is not a good reason to place observatories on remote mountain tops? to reduce light distortion to be able to observe at radio wavelengths to reduce light absorption to reduce light pollution

to be able to observe at radio wavelengths

What is the purpose of adaptive optics?

to eliminate the distorting effects of atmospheric turbulence for telescopes on the ground

The stars in our sky twinkle in brightness and color because of ______.

turbulence in the Earth's atmosphere

Which of the following effects is caused by atmospheric turbulence?

twinkling of stars

The planet in our solar system with the highest average surface temperature is:

venus

Which of the following forms of light can be observed with telescopes at sea level? Select all that apply. Select all that apply. X rays ultraviolet light visible light infrared light radio waves

visible light radio waves

visited all four giant planets between 1979 and 1989

voyager 2

Gamma rays have a very small ______.

wavelength

Suppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2. In that case

we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy 2

Suppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2. In that case _________.

we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy 2

The star Betelgeuse is about 600 light-years away. If it explodes tonight,

we won't know about it until 600 years from now.

Listed following are distinguishing characteristics and examples of reflecting and refracting telescopes. Match these to the appropriate category. Reflecting telescopes

worlds largest telescope, most commonly used by professionals astronomers today, the hubble space telescope

If we imagine the history of the universe compressed into one year, dinosaurs became extinct

yesterday morning

If we imagine the history of the universe compressed into one year, dinosaurs became extinct _________.

yesterday morning