Astronomy Hw

From which of the following will a wave of light show the greatest gravitational redshift:

a white dwarf

A Congressman from Texas visits our National Observatory in Tucson, Arizona, and wants to be shown an object in the universe with the "biggest darn redshift you ever saw". What type of object should the astronomers show him?

a quasar

To predict whether a star will ultimately become a black hole, what is the key property of the star we should look at?

mass

Today, astronomers find compelling evidence that the energy source of the quasars and active galaxies is

matter falling toward a supermassive black hole at the center of a galaxy

Our Milky Way Galaxy is what type of galaxy?

spiral

What method was used to discover Pluto in 1929-1930?

take pairs of photographs several days apart and "blink" them

The large reservoir of comet nuclei far beyond Pluto, from which we believe new long-period comets come into the inner solar system, is called:

the Oort Cloud

Which theory of the Moon's origin do astronomers (and the evidence) favor:

the giant impact theory

Edwin Hubble developed a classification scheme for galaxies. By what characteristic did he classify galaxies?

their shape

Which of the following objects is considered useful to astronomers as a "standard bulb" for determining distances?

type Ia supernovae

After several decades of observation, astronomers have concluded that quasars are

very powerful and compact sources of energy at the centers of distant galaxies

A spot where magma rises to the surface can be seen as a

volcano

Which of the following statements about the nuclear bulge of our Galaxy is FALSE?

the best way to learn more about it is to observe higher energy radiation, such as ultraviolet and x-rays

Edwin Hubble was able to show that (with the exception of our nearest neighbors) the farther a galaxy is from us, the

the faster it is moving away from us

What have we learned from the work of Harlow Shapley and others about the location of the Sun in the Milky Way Galaxy?

we are in the disk of the Galaxy, about 3/5 of the way from the center Correct! Grade Summary

A single star in the process of forming starts by spinning slowly (while it is quite large and relatively cool.) As the star collapses under the pull of its own gravity, its size decreases. As a result, its rate of spinning:

will increase

Short-period comets like Comet Halley

you can't fool me, the only short-period comet we know is Halley

When one member of a binary star system is a black hole, and astronomers detect flickering x-rays coming from the system, where are these x-rays usually coming from?

from a disk of material around the black hole (material that has been pulled from the companion star and is falling toward the black hole)

What phase of the Moon must it be to have a lunar eclipse?

full moon

Which of the following has the highest frequency?

gamma rays

Layers of the Sun - inside to out

Core Radiative Zone Convective zone Photosphere Prominence Sunspot Corona

The first astronomer who did photometry in a systematic way (even though he did not have a telescope) was

Hipparchus

Which type of galaxy is observed to contain mostly older stars?

elliptical

Layers of Earth - Inside to out

Inner core Core Mantle Crust

Layers of Earth's atmosphere - Bottom to Top

Troposphere Stratosphere Mesosphere Ionosphere

The 17th century astronomer who kept a roughly 20 year continuous record of the positions of the Sun, Moon, and planets was:

Tycho Brahe

In the future, astronomers believe that the Milky Way Galaxy has additional collisions in store. Which of the following nearby galaxies are eventually going to collide with our own?

all of these

Astronomers now know that surrounding the main body of our Galaxy (which our various kinds of telescopes have shown to us) and our fainter halo of stars there is

an invisible halo made of what astronomers are calling "dark matter"

According to the general theory of relativity, the presence of mass

causes a curvature (or warping) of spacetime

Where would you look for the youngest stars in the Milky Way Galaxy?

in the disk

For galaxies that have super-massive black holes at their centers, how do astronomers find that the mass of the host galaxy and the mass of the black hole are related?

the more massive the galaxy, the more massive the central black hole

Which part of a comet is the DENSEST?

the nucleus

How do quasars demonstrate that the universe evolves with time?

the number of quasars reached a maximum some time ago, and now the numbers have been declining

According to Einstein's general theory of relativity, the stronger a star's gravity,

the slower time runs near it

The largest continental (highland) area on Venus is called:

Aphrodite

Which of the following types of stars will spend the longest time (the greatest number of years) on the main sequence?

K

How Bright the Stars Are: Because distance causes light to spread out and get dimmer, astronomers need to distinguish between the total energy output of a star, called its ______________ and how bright a star looks from Earth, called its ____________. For historical reasons, astronomers still use a system for how bright a star looks from Earth, which assigns a number to each star called its _________. The larger this number, the _______ the star.

Luminosity Apparent brightness Magnitude Fainter

Which of the following types of star is the coolest (has the lowest surface temperature)?

M

The gradual drifting of the Earth's continents and the formation of new mountains and great rifts under the ocean can all be explained by the theory of ________________. These movements are powered by the process of _________ of heat in the Earth's __________. The segments of the Earth's crust pull apart along great __________ and are forced under one another in _______________.

Plate tectonics Convection Mantle Rift zones Subduction zones

The largest volcano on Mars is called:

Olympus Mons (Mt. Olympus)

The Sun is so hot that its material is in the form of a _________. Gravity is always producing a force that tends to make the Sun collapse toward its center. To balance this force, the energy produced by nuclear fusion produces an outward _________, allowing the Sun to be in a condition of ___________. Inside the Sun, energy is transported via __________, where hot material rises and cooler material falls downward. Energy is also transported outward via ____________, but photons take between 100,000 and 1,000,000 years to reach the Sun's surface. On the other hand, ________ produced by nuclear fusion at the center reach the surface of the Sun in just a little more than 2 seconds.

Plasma Pressure Equilibrium Convection Radiation Neutrinos

The first evidence for the existence of an 11 year cycle of activity on the Sun came from the study of ___________. Key to all the activity that the Sun's outer regions experience is the idea that the Sun is a strong and complicated ________. Another part of the explanation of activity is that the Sun's spin is not the same as you change latitudes, a phenomenon known as ______________. We can detect activity in the Sun's outer regions in a variety of different ways. Bright "clouds" or regions in the chromosphere are called _________. Huge loops of hot gas, which can sometimes erupt, are known as ________. Most violent are the very dramatic and rapid eruptions of material and energy from the Sun are called _______.

Sunspots Magnet Differential rotation Plages Prominences Flares

The Earth's escape speed (the speed you need to get away forever) is about 25,000 miles per hour. Escape speed depends on the gravity of the object trying to hold the spacecraft from escaping. Based on your understanding of gravity, how will the escape speed from the Moon compare to the escape speed from Earth?

The Moon's escape speed will be smaller than Earth's

Please match the following instruments with the band of the electromagnetic spectrum they are used to observe (a band may be used more than once):

The SOFIA Airborne Observatory - infrared Very Large Array in New Mexico - radio The Chandra Space Telescope - x-rays Arecibo Telescope in Puerto Rico - radio The Very Large Telescope (4 of the in Chile) - visible The Yerkes Observatory Refractor - visible

How does the Sun influence the tides that we experience on Earth?

The Sun also raises tides on Earth, but its effect is smaller than that of the Moon

The Astronomical Unit (AU) is defined as

The average distance of the Earth from the Sun

From the list below, select the main reason that the following happens (match the phenomenon in the left column with the reason for it).

The cycle of day and night - The Earth turns The different amounts of daylight during the cycle of the seasons - The Earth's axis is tilted The phases of the Moon - The Moon orbits the Earth Eclipses don't happen every month - The Moon turns on its axis

Which of the following statements about Saturn's rings is TRUE?

The rings are made of billions and billions of individual "moonlets" (small chunks)

Astronomers observe a typical star using a telescope and a spectrometer. They will see:

more than one of these

Which of the following is the smallest?

neutron star

What phase of the Moon must it be to have a solar eclipse?

new moon

The most abundant gas in the Earth's atmosphere is

nitrogen

A very wealthy donor decides to give a large sum of money to your college or university to build the world's largest visible-light gathering telescope. From an astronomical perspective, where would be the best location to put such a telescope?

on a tall, dry mountain peak

When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it:

retrograde motion

According to the theory of plate tectonics,

slow motions within the mantle of the Earth move large sections of the crust around

The largest impact basin on Mercury (located on that part of the planet which is closest to the Sun at noon) is called:

Caloris

Our two neighbor planets have similarities, but also many differences. One similarity is that both their atmospheres have _______ as the main gas. But because of its lower ________, Mars has lost much of its early atmosphere, while Venus has not. From orbit, Mars's air is pretty transparent, except when there are global __________. The air on Venus is never transparent; all we can see are the tops of the ________. One kind of geological feature that both planets have are __________.

Carbon dioxide Gravity Dust storms Clouds Mountains

Your friend, a graduate student in astronomy, is giving you a special tour of the local observatory. You notice that you are viewing the image from the big telescope from underneath the primary mirror; the beam of light has come through a small hole in the main mirror to an eyepiece below. This telescope uses what focusing arrangement?

Cassegrain focus

The Renaissance astronomer who wrote the pioneering book that suggested the Earth probably orbits the Sun (instead of the other way around) was:

Copernicus

Even though ancient thinkers considered the circle to be the perfect form and thus imagined that the planets followed orbits that were circles, in fact the orbit of a planet is in the shape (or figure) of an __________. Planets orbit the Sun, which is at located at one of the ______ of this figure. The line across the widest part of this figure is called its _______. Some of the planets orbits are almost circles and others are more stretched out. The degree to which the shape of the orbit resembles a circle is called its ________.

Eclipse Foci Major axis Ecentricity

The source of the Sun's energy was only identified in the 20th century; before that humans enjoyed sunshine without having any explanation of its source. Today we know that the source of the Sun's energy is the conversion of mass into ________, through the process of nuclear ________. For this process to star, temperatures in the core of a star must be at least __________ degrees. If the temperature is hot enough, two protons (hydrogen nuclei) can turn into a ___________ nucleus, an antimatter particle called a __________, and a ______________. This is the first step in a three-step sequence of nuclear reactions that astronomers call the _______________.

Energy Fusion 12 million Deuterium Positron Neutrino Proton-proton chain

Match the following ancient thinkers with their achievements

Eratosthenes: Measuring the size of the Earth Hipparcus: Developing a pioneering star catalog Aristarchus of Samos: Suggesting that the Earth moved around the Sun Ptolemy: Developing a model of the solar system that fit with observations

In what fundamental way did the work of Galileo differ from his predecessors who had thought about the sky?

Galileo used instruments and experiments to show him what nature was doing, instead of relying on pure logic

Why is an absorption spectrum especially useful for astronomers?

It has dark lines in it that allow astronomers to determine what elements are in the star

The lakes found in the north polar region of Titan are filled with liquid

methane

The moon Triton orbits which of the planets?

Neptune

The method of measuring distance in space using parallax is equivalent to surveyors on Earth doing _______________. The smaller the parallax of an object, the greater its __________. When we measure parallax, the distance between the two observers (or two vantage points) is called the ___________. The first parallax to a star was not measured until 1838 because the stars are so _______________. The distance at which a star has a parallax of one second of arc is called a __________. In 1989, astronomers launched a satellite called __________ to measure parallax even better from outer space.

Triangulation Distance Baseline Far away Parsec Hipparcos

What specific event really made it possible for the three laws of planetary motion to be discovered?

Tycho Brahe died and his assistant was able to get full access to his data

The planet that orbits "on its side" (i.e. has its rotation axis perpendicular to the plane of its orbit) is:

Uranus

Of the following planets, which do NOT have satellites (moons)?

Venus

Which of the following is NOT a correct statement about the rotation of Venus?

Venus rotates in roughly the same time period as Earth

Which of the following has the greatest average energy of random atomic and molecular motion?

a cube of the Sun

Astronomers believe that Jupiter's strong magnetic field is caused by

a huge layer of metallic hydrogen inside Jupiter

Within a constellation, a smaller, recognizable pattern of stars is often called:

an asterism

A graduate student is trying to follow the weather on Jupiter for her PhD thesis. To see the big weather patterns in the upper atmosphere of the planet, she needs to have excellent resolution. What type of telescope would be best for her to use?

a large reflector located in orbit above the Earth's atmosphere

What happens as an electron falls from a higher level to a lower level in an atom?

a photon is given off

Astronomers call a ball of matter that is contracting to become a star

a protostar

The Van Allen belt is

a region of trapped charged particles in the Earth's magnetosphere

The typical meteor is

a small solid particle, no bigger than a pea

To break up light into the component colors that it contains, astronomers use a device called:

a spectrometer

Consider a circle with a diameter D = 12 cm. a) What is the semimajor axis of this circle in cm? b) What is the eccentricity e of this circle?

a) Semimajor axis = 6 b) e = 0

We believe the maria on the Earth's Moon are:

ancient impact craters in which lava beds welled up from inside the Moon

To overcome the problems that blur images and don't provide the best resolution from Earth, astronomers have started using flexible mirrors that change shape many times each second. This technique is called:

adaptive optics

Why do many people consider Isaac Newton one of the greatest scientists who ever lived?

all of the listed reasons

The Red Spot of Jupiter is:

all of these

A friend of yours (who has not had the benefit of an astronomy course) tells you about a report he has read in a tabloid newspaper. They claim that on the dark side of the Moon, which is never in sunlight, there is a secret base of aliens who cannot stand light, and who send UFO's to Earth under the cover of darkness. Ignoring the UFO claim for a moment, what is the scientific error in this story?

all sides of the Moon are illuminated by sunlight in the course of a month; there is no dark side

Why were asteroids not discovered until the 19th century?

asteroids are generally small compared to planets and require a good telescope and patient searching to spot them

If you could see the new moon, at what time of day (roughly) would it rise?

at sunrise

Where on Earth do stars always circle the zenith (and never rise and set)?

at the north pole

How fast do electro-magnetic waves travel?

at the speed of light

The bluish color that makes the atmosphere of Neptune so beautiful to the human eye is caused by the interaction of sunlight with what gas?

methane

Today, astronomers can measure distances directly to worlds like Venus, Mars, the Moon, or the satellites of Jupiter by

bouncing radar beams off them

More than 75% of the known asteroids:

can be found in a belt between Mars and Jupiter

The most important function of an astronomical telescope is to:

collect as much light as possible and bring it to a focus

The 88 sectors into which astronomers today divide the celestial sphere (the whole sky) are called:

constellations

The Sun's chromosphere and corona were discovered

during total eclipses of the Sun

At the largest and most modern astronomical observatories on Earth today, which of the following regularly happens to the image formed by the telescope?

it is recorded using an electronic detector called a CCD for later analysis

In radioactive dating, the measure scientists use to note how long (on average) a particular radioactive nucleus will take to decay is called its

half-life

When it comes to our place in the solar system today, which model do we accept?

heliocentric

Atoms typically consist of electrons, protons, and neutrons. The most common isotope of one element, however, only has two of these three types of particles. This element is:

hydrogen

If you want to find stars that are just being born, where are the best places to search?

in giant molecular clouds

The idea that objects (in the absence of an outside force) tend to continue doing what they are already doing is called the law of

inertia

When an atom has lost one or more electrons, it is said to be:

ionized

Which of the following statements about the force of gravity is FALSE?

its strength is inversely proportional to the mass: the more mass, the less gravity

Which of the following is a way that the planet Mercury is similar to the Moon?

its surface is heavily cratered

Which of the following ways that jovian (giant) planets differ from the terrestrial planets is NOT CORRECT?

jovians (being larger) rotate significantly more slowly than terrestrials

In a bad late-night science fiction film, a villain is using a large collection of rare radioactive atoms as energy for a weapon to threaten the good guys. The atoms have a half-life of 1 hour. The villain has 4 kilograms of the radioactive material now, and he needs a minimum of 1 kg. for his weapon to work. After how much time will the weapon no longer be a threat?

just a little after 2 hrs

We have two waves of light, A and B. Wave A has a higher frequency than wave B. Then wave B must have:

longer wavelength

The Stefan-Boltzmann Law relates the energy flux coming from a blackbody (such as a star) to its:

temperature

If the Earth goes around the Sun, why is the ecliptic not lined up with the celestial equator?

the Earth's axis is tilted by about 23 degrees from the vertical

What was a surprise to astronomers when they carefully examined Neptune with the Hubble Space Telescope in 1994?

the Great Dark Spot had disappeared

We observe a glowing cloud of gas in space with a spectroscope. We note that many of the familiar lines of hydrogen that we know on Earth seem to be in a different place. They are shifted toward the blue or violet end of the spectrum compared to their positions in the spectrum of glowing hydrogen gas on Earth. From this we can conclude that:

the cloud is moving toward us

Which of the following is NOT evidence that objects from space collide with the Earth?

the crater at the top of the Mount St. Helens volcano

Which of the following statements about temperature changes on Mercury is correct?

the difference in temperature between Mercury's daylight side and its night side is the greatest difference of any planet in the solar system

Which of the following is a characteristic of degenerate matter in a white dwarf star?

the electrons get as close to each other as possible and resist further compression

What is the cause of its many volcanic/geyser-like eruptions on the moon Io?

the gravitational stress of being so close to Jupiter and its other large moons heats the Io's inside

If you could somehow return to the Earth in many millions of years, which of the following will be different?

the length of the month

Which of the following is NOT a way that Venus resembles the Earth?

the thickness and pressure of its atmosphere

Which of the following characteristics do all four terrestrial planets have in common?

they all have solid surfaces with signs of geological activity on them

When the outer layers of a star like the Sun expand, and it becomes a giant, which way does it move on the H-R diagram?

toward the upper right