Astro 101 Online Quiz ?'s

Compared to a photon that has a wavelength equal to 8000 , a photon having a wavelength equal to 4000 has a. 1/2 the energy. b. double the energy. c. exactly the same energy. d. twice the frequency. e. both choices (b) and (d) are correct

both choices (b) and (d) are correct

The cloud of gas and dust out of which the Solar System is believed to have formed is known as the a. solar nebula. b. asteroid belt. c. cometary cloud. d. reactive region. e. protokaryotic cloud.

solar nebula.

The apparent path that the Sun makes around the celestial sphere during the course of a year is called a. the ecliptic. b. the horizon. c. the circumpolar zone. d. the south celestial pole. e. the celestial equator.

the ecliptic.

The bright star Altair is located at a distance of about 5 parsecs from Earth. What parallax would you expect to be observed for this star? a. 0.2 arcsec. b. 0.2 seconds. c. 0.2 degrees. d. 5 arcsec.

0.2 arcsec.

Suppose you are driving 60 miles per hour. What is your rate of speed in miles per minute? (That is, how many miles are you traveling in each minute?) a. 3,600 miles per minute. b. 1/60 miles per minute. c. 1 mile per minute. d. 360 miles per minute. e. 60 miles per minute.

1 mile per minute.

How would we write the number 0.0000000001 using scientific notation?

1 x 10 ^-10

If the population of human beings keeps increasing on this planet, estimates are that we will soon have more than ten billion members of our species on the increasingly crowded surface of the Earth. How would you express this number (ten billion) using scientific (or, "PowerofTen") notation?

1 x 10^10

The average distance from the Earth to the sun is equal to: a. 0.25 Astronomical Units (AU). b. 0.5 AU. c. 1.0 AU. d. 1.5 AU. e. 2.0 AU.

1.0 AU

The Sun is an enormous ball of gas. Left to itself, a ball of so many gas atoms should collapse under its own tremendous gravity. Why is our Sun not collapsing? a. The sun is, in fact, slowly collapsing at a rate of about 250 feet per century. b. King Kong lives in the center of the Sun, and holds up the outer layers. c. Neutrinos from the core exert an enormous pressure on the layers of the Sun as they travel outward, and keep our star from collapsing. d. The gravity of the planets around the Sun pulls its material outward, preventing collapse. e. Nuclear fusion in the core keeps the temperature high, and the resulting gas pressure and radiation pressure inside the Sun exactly balance gravity

Nuclear fusion in the core keeps the temperature high, and the resulting gas pressure and radiation pressure inside the Sun exactly balance gravity

Astronomers refer to the distance that light travels in one year as a. one year. b. one nebula. c. one mile. d. one light year. e. None of the above: astronomers have no specific term that is defined to be the distance that light travels in one year!

One light year

When a large atomic nucleus breaks apart (or is broken apart) into two or more smaller pieces and releases energy, it is called a. nuclear fusion. b. the protonproton chain. c. ionization. d. hydrostatic equilibrium. e. nuclear fission.

nuclear fission.

Astronomers currently believe that a Type Ia supernova a. occurs when a white dwarf accumulates matter from a companion star and steadily increases its mass until a critical density is reached at (or near) its center, triggering a thermonuclear runaway that completely incinerates the star. b. results from the corecollapse, and subsequent envelope ejection, of a highmass star (i.e., one born with an initial mass greater than about 8 MSun. c. occurs when an isolated white dwarf (i.e., one without a "companion star") cools down to a critical temperature (about 100 K), at which point it suddenly collapses down to the size of a small city, and ejects its envelope. d. occurs when a neutron star collides with a white dwarf. e. occurs when a white dwarf accumulates matter from its own planetary nebula, gains mass, and is induced to explode

occurs when a white dwarf accumulates matter from a companion star and steadily increases its mass until a critical density is reached at (or near) its center, triggering a thermonuclear runaway that completely incinerates the star.

As astronomers use the term, the parallax of a star is a. the amount of time it takes a star to circle once around a celestial pole in the sky. b. the time it takes for a star's apparent position in the sky to move one arcsecond due to the precession of Earth's axis. c. always equal to one astronomical unit. d. one half the angle that a star shifts when viewed from opposite sides of the Earth's orbit around the Sun. e. one half of the Doppler shift measured in a star's spectrum due to its radial velocity towards or away from the Earth.

one half the angle that a star shifts when viewed from opposite sides of the Earth's orbit around the Sun.

When a positron and an electron collide, they produce: a. a hydrogen nucleus. b. a deuterium nucleus. c. a neutron. d. pure energy in the form of a photon. e. a neutrino.

pure energy in the form of a photon.

The bright star Pollux is located at a distance of about 10 parsecs from Earth. What parallax would you expect to be observed for this star? a. 0.1 arcseconds. b. 10 arcseconds. c. 2.5 arcseconds. d. 0.1 degrees. e. None of the above answers are correct, since it is impossible to know the parallax that will be observed for a star by only knowing its distance.

0.1 arcseconds.

At a distance of about 4 LY, Alpha Centauri is the closest star to the Earth (other than the Sun) and is clearly visible to the unaided eye for observers located in the Southern hemisphere. If it were located instead at a distance of 8 LY, its apparent brightness in our night sky would be a. half of its present value. b. four times its present value. c. 1/4 its present value. d. the same as its present value. e. twice its present value.

1/4 its present value.

In class and in your textbook reading (section 2.2.3) you learned about the technique by which Eratosthenes estimated the circumference of the Earth. Specifically, he found the circumference of the Earth to be roughly 250,000 stadia (note that stadia were a unit of distance used in ancient times). Carefully reread textbook section 2.2.3 again now, and then answer the following question: If Eratosthenes had measured the angle that the Sun made with the vertical at noon on June 22 in Alexandria to have been 14 degree instead of 7 degree, approximately what value would he have estimated for the Earth's circumference? (Give answer in units of stadia.) a. 62,500 stadia. b. 125,000 stadia. c. 250,000 stadia. d. 500,000 stadia. e. 1 million stadia.

125,000 stadia.

Polaris is currently located very close to the North Celestial Pole. However, due to the effects of precession, we know that it has not always been located as close to the North Celestial Pole as it is today. Of the following, at which point in the past was Polaris located farthest from the North Celestial Pole? a. 12 hours ago. b. 365 days ago. c. 100 years ago. d. 13,000 years ago. e. 26,000 years ago.

13,000 years ago.

Suppose that, at aphelion, a planet's orbital speed around the Sun is 20 km/sec. Which one of the following could be the speed of that planet when it is at perihelion? a. 10 km/sec. b. 0 km/sec. c. 15 km/sec. d. 25 km/sec. e. None of the above answers is correct, since planets orbit the Sun at exactly the same speed, regardless of their distances from the Sun.

25 km/sec.

Suppose an asteroid orbits the Sun exactly once every 8 years. Its mean orbital distance to the Sun must be equal to a. 4 AU. b. 8 AU. c. 4 LY. d. 64 AU. e. 4 kilometers.

4 AU

What is the approximate range of wavelengths for the visible part of the electromagnetic spectrum? a. 1 to 1000 micrometers. b. 400 to 700 nanometers. c. All wavelengths smaller than 400 nanometers. d. 20 to 400 nanometers. e. 400 to 700 meters.

400 to 700 nanometers.

Water waves are striking a shoreline with a frequency of 3 waves per second. If the waves have a wavelength of 2 meters per wave, then the speed of the waves is a. 1.5 meters per second. b. 5 meters per second. c. 2/3 meters per second. d. 2 meters per second. e. 6 meters per second.

6 meters per second.

The temperature of the Sun's photosphere (i.e., the Sun's "surface") is most nearly equal to: a. 100 K b. 6,000 K c. 6,000,000 K d. 15,000,000 K e. 6 x 109 K

6,000 K

The H spectral line of the Balmer series of hydrogen has a wavelength of 6563 Angstroms for a hydrogen source that is at rest. Of the following, which observed wavelength of this line in a star's spectrum would indicate that the star is approaching us (i.e., moving towards us) at the greatest speed? a. 6530 Angstroms. b. 6540 Angstroms. c. 6563 Angstroms. d. 6570 Angstroms. e. 6600 Angstroms.

6530 Angstroms.

Which of the following has the greatest density? a. A cubic meter of wood. b. A cubic meter of snow. c. A cubic meter of feathers. d. A cubic meter of gold. e. None of the above choices is correct since, by definition, a cubic meter of any substance will have the same density

A cubic meter of gold.

Who "pays the bill'' for the energy generated by nuclear fusion in the Sun? In other words, from where does all of the energy pouring out of the Sun ultimately come? a. Heavy nuclei are breaking apart into lighter nuclei, releasing energy. b. A little bit of mass is lost in each nuclear reaction, and is turned into energy that is, the Sun is (slowly) losing mass! c. Material is falling into the Sun and being vaporized to produce energy. d. American taxpayers pay this bill, as they do so many others. e. The Sun is spinning more slowly as time goes on; rotation energy is being lost.

A little bit of mass is lost in each nuclear reaction, and is turned into energy that is, the Sun is (slowly) losing mass!

The asteroid belt is: a. A new fashion accessory being sold by NASA to raise funds for future missions. b. A spherical region of icy chunks of material surrounding the Sun at a distance of about 1 LY. c. A series of orbital zones around the Moon, from which fragments drop down to form craters on its surface. d. A spherical region surrounding the Earth at the distance of the Moon. e. A region between the orbits of Mars and Jupiter in which many small, stony, or metallic objects orbit the Sun.

A region between the orbits of Mars and Jupiter in which many small, stony, or metallic objects orbit the Sun.

Which of the following solar system bodies is most likely to NOT have experienced differentiation? a. Venus. b. A small asteroid. c. Jupiter. d. Ganymede, the largest moon in the solar system. e. Earth.

A small asteroid.

Roughly how long does it take for the energy from photons created by hydrogen fusion at the center of the Sun to reach the surface of the Sun? a. About 2 seconds. b. About 3 or 4 days. c. About 10 billion years. d. About 1,000,000 years. e. About 8 minutes

About 1,000,000 years.

If a star is 10 parsecs away, roughly how long ago did the light that we see coming from it begin its journey toward us? a. About 1 million years. b. About 10 days. c. About 30 years. d. About 10 seconds. e. None of the above answers are correct, since the light from all stars, including this one, reaches us instantly since light travels at an infinite speed!

About 30 years.

Kepler's Laws can give us the relative distances of the planets in our solar system. To convert these relative distances into actual distances, however, it is first necessary to: a. Measure the length of the year exactly. b. Accurately measure the actual distance to one of the planets. c. Accurately measure the radius of the Earth. d. Measure very precisely the time that it takes for the Earth to spin once on its axis. e. Accurately measure the mass of the Earth.

Accurately measure the actual distance to one of the planets.

Which of the following has the lowest mass? a. A neutron. b. The nucleus of a helium atom. c. A hydrogen atom. d. An electron. e. A proton

An electron.

What mechanism do we believe to be responsible for the fact that most neutron stars are "born" spinning very rapidly? a. The young neutron star absorbs the spin of planets that are sucked into them during the collapse of the star. b. Angular momentum is conserved as the slowly rotating star collapses down to the very small size of the neutron star. c. The neutron star accretes matter from a close companion star and gets ``spun up''. d. It is a consequence of all the energy that is converted to matter during "corecollapse". e. None of the above choices is correct; young neutron stars typically take over a year to rotate even once!

Angular momentum is conserved as the slowly rotating star collapses down to the very small size of the neutron star.

Which ancient Greek thinker is known to have suggested that the Earth is moving around the Sun? a. Aristotle. b. Aristarchus. c. Plato. d. Hipparchus. e. All of the above thinkers are known to have considered a "heliocentric" cosmology

Aristarchus

Which of the following is a correct chronological sequence of famous thinkers, ordered from longest ago to most recent? a. Galileo, Copernicus, Aristotle, Ptolemy. b. Copernicus, Aristotle, Ptolemy, Galileo. c. Ptolemy, Aristotle, Copernicus, Galileo. d. Aristotle, Ptolemy, Copernicus, Galileo. e. None of the above represents a correct chronological sequence of famous thinkers.

Aristotle, Ptolemy, Copernicus, Galileo.

Which of the following statements about the life of a star with a mass equal to that of our Sun is correct? a. Before the star dies, it will fuse dozens of different kinds of elements in its core. b. The star will become a "red giant" star roughly 10 million years after it was born. c. As the star is dying, a considerable amount of its mass will be lost into space. d. After the star is no longer a main sequence star, there is no further fusion of hydrogen anywhere in the star. e. Fusion will end in the core of this star once iron has been produced there.

As the star is dying, a considerable amount of its mass will be lost into space

Which of the following concerning total solar eclipses is FALSE? a. Total solar eclipses are observed far less frequently from a given place on Earth than are total lunar eclipses. b. When totally eclipsed, the Sun's corona becomes visible. c. Total solar eclipses occur when the Earth moves into the Moon's shadow. d. At least one total solar eclipse is visible each month from some location on Earth's surface. e. Total solar eclipses always last a short amount of time never more than 10 minutes.

At least one total solar eclipse is visible each month from some location on Earth's surface.

What do we assume when we use a ``standard candle'' to determine the distance to an astronomical object? a. That the force of gravitational attraction is inversely proportional to distance squared. b. That the apparent brightness of an object decreases as the inverse square of the distance to the object. c. That we know the luminosity of the ``standard candle''. d. Both a and c above. e. Both b and c above.

Both b and c above.

Stars `A' and `B' have identical radii, and are both located the same distance from Earth. Star `A' has a surface temperature of 12,000 K, while star `B' has a surface temperature of 6,000 K. For an observer located on Earth, which of the following statements is TRUE? a. The two stars' continuous spectra will peak at the same wavelength. b. Star `B' will appear bluer in color than star `A'. c. Star `B' will appear fainter in the sky than star `A' will. d. Star `A' will appear appear bluer in color than `B'. e. Both choices (c) and (d) are true.

Both choices (c) and (d) are true.

Which one of the following statements concerning galaxies is true? a. All galaxies start out as elliptical galaxies, although some later evolve to become spirals and irregulars. b. Elliptical galaxies tend to have lots of interstellar gas and dust, out of which new stars are constantly forming. c. Collisions and mergers between galaxies can sometimes change a galaxy's type. d. 90% of all galaxies are spirals; elliptical and irregular galaxies are very rare. e. It is thought that all galaxies actually possess the same, basic, intrinsic shape the "type" that we see a galaxy to be only depends on the angle at which we happen to see it in the sky (i.e., its orientation).

Collisions and mergers between galaxies can sometimes change a galaxy's type.

What property of Jovian planets is less than that of terrestrial planets? a. Mass. b. Distance from the Sun. c. Density. d. Period of revolution around the Sun. e. Diameter.

Density.

If the Sun were to suddenly shrink down and become a black hole of the same mass, what would happen to the orbit of Earth? a. Earth would immediately fly radially away from the black hole, as though released from a stretched rubber band. b. Earth would drift off into space in the exact direction it was moving in its orbit when the Sun became a black hole, since the Sun's gravity would vanish when it became a black hole. c. Earth would slowly spiral towards the black hole over a few years before being consumed by it. d. Earth's orbit would not change. e. Earth would be immediately (i.e., in less than a second) sucked into the black hole because of the intense gravity.

Earth's orbit would not change.

Deep inside a red supergiant star near the end of its life are several concentric shells of different elements around a central core. What are the properties of these layers, going from outside inward? a. Element nuclei get heavier, temperature decreases, and time for each layer to develop decreases. b. Element nuclei get heavier, temperature decreases, and time for each layer to develop increases. c. Element nuclei get heavier, temperature increases, and time for each layer to develop decreases. d. Element nuclei get lighter, temperature increases, and time for each layer to develop increases. e. Element nuclei get heavier, temperature increases, and time for each layer to develop increases

Element nuclei get heavier, temperature increases, and time for each layer to develop decreases.

Suppose that you observe a galaxy that appears to be rather spherical in shape, and find that it contains mostly old stars spread smoothly throughout its volume. You also discover that it has little interstellar gas or dust. What type of galaxy are you most likely observing? a. Barred spiral. b. Irregular. c. Unbarred (or, "regular") spiral. d. Elliptical. e. This galaxy has about an equal likelihood of being any one of the above galaxy types.

Elliptical.

According to Kepler's 2nd Law, an object in the Solar System that has a very eccentric orbit, which carries it far beyond the orbits of the planets, should spend the majority of its time: a. In the asteroid belt. b. Inside of the Sun. c. Close to the Sun. d. Close to the planets. e. Far from the Sun and planets

Far from the Sun and planets

In what fundamental way did the work of Galileo differ most from his ancient predecessors who had thought about the sky? a. Galileo relied on experiments to test theories, and rejected those theories whose predictions conflicted with what he observed. b. Galileo consulted many authorities before coming to scientific conclusions, instead of working on his own. c. Galileo believed that the Earth was the center of the solar system, and that everything revolved around it. d. Galileo translated the works of the ancient Greek astronomers, and relied on their abilities to think through difficult problems without actually observing phenomena. e. Galileo relied on the revelations of the Bible to tell him what was happening in the sky

Galileo relied on experiments to test theories, and rejected those theories whose predictions conflicted with what he observed.

The scientist who worked out the mathematics of the connections between electricity, magnetism, and light in the 19th century was: a. Gustav Kirchoff. b. Christian Doppler. c. Josef Fraunhofer. d. Isaac Newton. e. James Clerk Maxwell.

James Clerk Maxwell.

In a binary system in which a red giant and black hole are in orbit about a common center of mass, what is believed to be responsible for the occasional bursts of Xrays seen to come from near the black hole's event horizon? a. The ultimate collapse of the black hole's companion star into a white dwarf. b. Heating of the infalling material caused by internal friction in the accretion disk. c. Ionization of material caused by intense radiation from nearby stars. d. Ionization of material caused by tidal forces. e. The fusion of hydrogen directly into gold within the inner part of the accretion disk.

Heating of the infalling material caused by internal friction in the accretion disk.

The second most abundant element in the Sun, by mass, is: a. Iron. b. Hydrogen. c. Carbon. d. Helium. e. Oxygen

Helium

One of the great triumphs of spectroscopy was when astronomers identified a new element in the spectrum of the Sun; this element was only later found on Earth. Today, this element is called: a. Oxygen. b. Hydrogen. c. Solarium. d. Lithium. e. Helium.

Helium.

Astronomers must often know the distance to a star before they can fully understand its characteristics. Which of the following properties of a star typically requires a knowledge of distance before it can be determined? a. Its luminosity. b. Its temperature. c. Its apparent brightness. d. Its radial velocity. e. All of the above require knowledge of distance to determine.

Its luminosity.

Which of the following statements about forces is FALSE? a. Forces can change the momentum of a body. b. If no external forces act on it, an object that is moving with a constant velocity will continue to move with the same, constant, velocity it will not speed up, slow down, or change direction. c. Forces always occur in equal and opposite pairs. d. Forces can cause an acceleration to take place. e. If there is no force acting on an object, it must be at rest with respect to surrounding objects.

If there is no force acting on an object, it must be at rest with respect to surrounding objects.

The star Betelgeuse in the constellation of Orion is estimated to be 500 light years (LY) away from Earth. Suppose that right now, Betelgeuse explodes as a supernova. In what year would people on Earth first become aware that Betelgeuse had exploded? a.Sometime in the year 2019 (i.e., in about 500 days from today). b. In the year 2018 (i.e., we would learn about Betelgeuse exploding right away). c. In 2118 (i.e., about 100 years from now). d. In 2518 (i.e., in about 500 years from now). e. About 1518 (i.e., we would have already learned of Betelgeuse's demise about 500 years ago).

In 2518 (i.e., in about 500 years from now).

Which of the following statements about the Crab Nebula is FALSE? a. Inside the nebula, astronomers have discovered many newly formed, highmass stars (i.e., stars with greater than eight times the mass of the Sun). b. The neutron star inside the Crab Nebula shows clear evidence of slowing down just a little bit in its rotation over time. c. It is the remnant of a supernova explosion first seen on Earth in 1054 AD. d. In addition to pulses of radio energy, we can observe pulses of visible light and Xrays from the Crab Nebula's "pulsar". e. The Crab Nebula glows with radiation at many wavelengths, and its overall energy output is more than 100,000 times that of the Sun.

Inside the nebula, astronomers have discovered many newly formed, highmass stars (i.e., stars with greater than eight times the mass of the Sun).

When an atom has lost one or more electrons, it is said to be: a. Ionized. b. In its ground state. c. Excited. d. Blueshifted. e. Redshifted.

Ionized.

What is so "catastrophic" about electrons and protons being forced together in the iron core during the first moments of a corecollapse supernova explosion? a. The combining of protons with electrons produces the element helium, a very "heavy" element, whose gravity causes the core of the star to collapse. b. When protons and electrons combine, they "annihilate" and release pure energy, which blows up the star immediately. c. It is the electrons, now being destroyed, which were providing much of the core's pressure support against gravitational collapse. d. The energy released when this happens makes antineutrons combine with neutrons which releases a tremendous amount of energy. e. This question has no correct answer since electrons and protons can never be "forced together", even in the extreme conditions that exist at the start of a corecollapse supernova.

It is the electrons, now being destroyed, which were providing much of the core's pressure support against gravitational collapse.

When a white dwarf star has matter from a companion star "dumped" onto it, it can erupt as a nova. As a result of this eruption, what do astronomers believe happens to the white dwarf? a. It is thought to change very little. b. It is ejected from the binary star system. c. It merges with the companion star. d. It is destroyed by the sudden burst of fusion. e. It is transformed into a neutron star.

It is thought to change very little.

In terms of size (i.e., radius), which of the following represents a correct sequence, ordered from largest to smallest: a. Saturn, Jupiter, Earth, Pluto. b. Earth, Jupiter, Saturn, Pluto. c. Jupiter, Saturn, Earth, Pluto. d. Pluto, Earth, Jupiter, Saturn. e. None of the above represents a correct sequence.

Jupiter, Saturn, Earth, Pluto.

In which one of the following situations would you feel ``weightless''? a. Flying inside a commercial airplane at a constant speed. b. Standing on Earth in an elevator as it starts to move quickly upward. c. Driving in a car as it turns sharply at an intersection. d. Living inside the Space Station as it orbits around the Earth. e. Standing on Earth in an elevator that is moving downward at a constant speed.

Living inside the Space Station as it orbits around the Earth.

Which of the following is the correct life sequence for a lowmass star? a. Main sequence, white dwarf, red giant. b. White dwarf, red giant, main sequence. c. Main sequence, red giant, white dwarf. d. Red giant, main sequence, white dwarf. e. White dwarf, main sequence, red giant.

Main sequence, red giant, white dwarf.

Which one of the following planets contains the largest known volcano in the Solar System? a. Mars b. Mercury c. Earth d. Venus. e. Jupiter.

Mars

Which two planets have no moons? a. Mars and Neptune. b. Venus and Mars. c. Mercury and Venus. d. Mercury and Earth. e. Uranus and Neptune.

Mercury and Venus.

In what part of the sun is the fusion of hydrogen occuring today? a. Only in the corona. b. Only in the central, "core" regions of the sun. c. Pretty much throughout the sun. d. Only right near the photosphere. e. Fusion of hydrogen is not occurring anywhere in the sun anymore!

Only in the central, "core" regions of the sun.

Which of the following statements about Pluto is false? a. Pluto has several moons. b. Pluto has an orbit that is more inclined and more eccentric than any of the 8 planets. c. Pluto has a solid surface. d. Pluto is just a bit larger than Earth's Moon. e. Pluto is now classified as a "dwarf planet".

Pluto is just a bit larger than Earth's Moon.

Which ancient thinker wrote Tetrabiblos, the foundational book on astrology that astrologers still consult today? a. Plato. b. Eratosthenes. c. Aristotle. d. Ptolemy. e. Hipparchus.

Ptolemy

Far away from a black hole (i.e., say, at least 100 LY from it), which of the following is a possible way to detect it? a. Look for the neutrinos that always escape from the event horizon. b. Look for the pulsed radio waves it gives off as it rotates like a lighthouse. c. Notice what a large amount of star light it blocks from behind it. d. Search for xrays being given off as it ``eats'' part of a companion star. e. None of the above astronomers currently know of no way to detect a black hole!

Search for xrays being given off as it ``eats'' part of a companion star.

Consider the following four constituents of the Solar System: (1) Jupiter; (2) Sun; (3) comets; (4) moons and rings of planets. Which of the following represents the proper ordering, arranged from MOST massive to LEAST massive (when considering a class of objects like comets or moons and rings, this means the sum total of all of the comets or moons and rings combined): a. Jupiter, Sun, Comets, moons and rings. b. Comets, Jupiter, Sun, moons and rings. c. Moons and rings, Sun, Jupiter, comets. d. Sun, Jupiter, comets, moons and rings. e. Sun, comets, Jupiter, moons and rings.

Sun, Jupiter, comets, moons and rings.

The reason that sunspots appear darker than the regions surrounding them is: a. Sunspots represent shadows cast by nearby mountainous regions on the Sun's surface. b. Sunspots represent regions on the Sun's surface that are cooler than the surrounding gases. c. Sunspots arise from gases falling into the sun, and thus the light they emit is strongly redshifted towards the "dark'' end of the visible spectrum. d. Sunspots are composed of nearly pure iron, which does not emit much visible light. e. Sunspots represent lakes of water on the Sun's surface, which do not emit much light.

Sunspots represent regions on the Sun's surface that are cooler than the surrounding gases.

The first successful detections of stellar parallax were made in which century? a. The 5th century BC. b. The 2nd century, AD. c. The 16th century, AD. d. The 19th century, AD. e. We have never successfully detected stellar parallax.

The 19th century, AD.

Jupiter's radius is roughly 10 times that of the Earth. Assuming the Earth and Jupiter to be spheres, about how many times larger is Jupiter's surface area than that of the Earth? a. Jupiter's surface area is the same as that of the Earth. b. Jupiter's surface area is 4pi x 10^2 times larger than that of the Earth. c. The Jupiter's surface area is 100 times larger than that of the Earth. d. Jupiter's surface area is pi x 10^2 times larger than that of the Earth. e. Jupiter's surface area is 100 times larger than that of the Earth.

The Jupiter's surface area is 100 times larger than that of the Earth

The ancient Greeks identified 7 objects that change their location night-to-night relative to the background, "fixed" stars of the celestial sphere. They dubbed these objects the "wanderers". Which one of the "wanderers" wanders the most (i.e., changes its position the most from one night to the next) relative to the fixed stars of the celestial sphere? a. The Moon. b. Polaris, the North Star. c. Mars. d. The Sun. e. Venus.

The Moon

Which of the following is NOT an argument for showing that the Earth must be round? a. The elevation of the North Star above the horizon changes as we travel to different latitudes. b. When a ship travels a large distance away, we see the bottom part of the ship (the hull) disappear first and its top (the mast) disappear last. c. During an eclipse of the Moon, the shadow of the Earth is always seen to be a curve rather than a straight line. d. Photographs of the earth from space always show a round body. e. The Sun is seen to be located within different constellations during the course of a year.

The Sun is seen to be located within different constellations during the course of a year.

The Sun's radius is roughly 100 times that of the Earth. Assuming both the Sun and Earth to be spheres, about how many times larger is the Sun's circumference than that of the Earth? a. The Sun's circumference is 2 pi x 100 times larger than that of the Earth. b. The Sun's circumference is 100 times larger than that of the Earth. c. The Sun's circumference is 10 times larger than that of the Earth. d. The Sun's circumference is 2pi times larger than that of the Earth. e. The Sun's circumference is the same as that of the Earth.

The Sun's circumference is 100 times larger than that of the Earth.

The Sun's radius is roughly 100 times that of the Earth. Assuming the Earth and Sun to be spheres, about how many times larger is the Sun's surface area than that of the Earth? a. The Sun's surface area is the same as that of the Earth. b. The Sun's surface area is 4pi x 100^2 times larger than that of the Earth. c. The Sun's surface area is 100 times larger than that of the Earth. d. The Sun's surface area is pi x 100^2 times larger than that of the Earth. e. The Sun's surface area is 10,000 times larger than that of the Earth.

The Sun's surface area is 10,000 times larger than that of the Earth.

What is true about the location of the "center of mass" of a binary star system that consists of two stars with different masses? a. The center of mass is located at the exact midpoint of the line connecting the centers of the two stars. b. The center of mass is located closer to the lower mass star. c. The center of mass is located closer to the higher mass star. d. The center of mass is located at the exact center of the star with the lower mass. e. The center of mass is located at the exact center of the star with the higher mass.

The center of mass is located closer to the higher mass star.

The Earth has a radius of 6400 km. The space station typically orbits the Earth at an altitude of 400 km above Earth's surface. To calculate the gravitational force exerted by the Earth on the orbiting space shuttle you must use Newton's law of gravitation: F= G M1 M2/ R^2 . For this situation, the R in Newton's gravity law represents: a. The radius of the Earth (i.e., 6400 km). b. The distance between the shuttle and the surface of the Earth (i.e., the shuttle's altitude, 400 km). c. The distance between the shuttle and the center of the Earth (i.e., 6400 km + 400 km = 6800 km). d. The mass of the Earth. e. This is a silly question, since there is no gravity in outer space where the space station is orbiting.

The distance between the shuttle and the center of the Earth (i.e., 6400 km + 400 km = 6800 km).

To leave the gravitational pull of the Earth, and explore other planets, a spacecraft must acquire a speed of at least: a. The so called "perigee velocity''. b. The speed that will get you a ticket on I8. c. The escape velocity of Earth. d. The circular satellite velocity around the Earth. e. 100 miles per hour.

The escape velocity of Earth.

Of the following experimental ``tests'' of Einstein's general theory of relativity, which one had actually already been observed at the time he proposed his theory in 1916? a. The fact that clocks on the top floor of a building run a little bit faster than do clocks in the basement, where the gravity is a little bit stronger. b. The fact that light leaving the surface of the Earth is found to be gravitationally redshifted when it is received by an orbiting spacecraft. c. The deflection of starlight during a solar eclipse. d. The extra advance in the perihelion point of the planet Mercury's orbit around the sun beyond what was predicted by Newton's theory of gravity. e. None of the above had been observed one of the amazing things about Einstein's General Theory of Relativity is that he proposed it before there was any observational evidence that it was correct.

The extra advance in the perihelion point of the planet Mercury's orbit around the sun beyond what was predicted by Newton's theory of gravity.

For a black hole, the size of the Schwarzschild radius depends only on: a. The mass enclosed within the event horizon. b. The radius of the star that collapsed to form the black hole. c. The chemical composition of the material that formed the black hole. d. The time since the black hole formed. e. None of the above every black hole has a Schwarzschild radius of exactly the same size.

The mass enclosed within the event horizon.

Suppose that instead of orbiting the Sun, the Earth was orbiting a star that had twice the mass the Sun has. If the orbit of the Earth around this new star has a semimajor axis of 1 AU, which of the following is true? a. The orbital period of the Earth around this new star will be less than one year. b. The orbital period of the Earth around this new star will be equal to one year. c. The orbital period of the Earth around this new star will be greater than one year. d. The speed of the Earth in its orbit around this new star will be less than the speed the Earth has in its orbit around the Sun. e. Both choices (c) and (d) are correct.

The orbital period of the Earth around this new star will be less than one year

With what speed does general relativity predict that gravitational waves should travel through space? a. The orbital speed of Earth around the Sun. b. The precise speed of sound in air. c. The speed of light. d. Precisely onehalf the speed of light. e. None of the above is correct general relativity predicts that gravitational waves should not actually "travel" at all they should remain precisely at the location at which they were produced.

The speed of light.

The absorption lines present in the spectra of white dwarfs usually show small red shifts. This is most likely due to the fact that: a. Their surface temperatures decrease with time, which makes the wavelengths of any absorption lines in their spectra look redder and redder. b. White dwarfs are usually rotating fairly quickly. c. The inhabitants of the white dwarfs are playing a trick on us. d. Most white dwarfs are moving away from us, because the massloss during the last stages of a lowmass star's evolution is often uneven, and this will usually give them a ``push'' that is typically not in our direction. e. The strong gravitational field that exists at their surface warps spacetime to such a degree that the light they give off is gravitationally redshifted as it leaves the white dwarf.

The strong gravitational field that exists at their surface warps spacetime to such a degree that the light they give off is gravitationally redshifted as it leaves the white dwarf.

You are creating waves in a shallow pan of water by gently tapping your finger on the water's surface once per second. If you increase the rate at which you tap the water's surface to two times per second, which of the following will happen? a. The wavelength of the resulting waves will be smaller than it was before. b. The frequency of the resulting waves will be lower than it was before. c. The speed with which the waves move through the water will be greater than it was before. d. The wavelength, frequency, and velocity of the waves will all remain unchanged. e. Both (a) and (c) will happen.

The wavelength of the resulting waves will be smaller than it was before.

Imagine yourself standing in a windowless room at an unknown location. Which of the following experiments will reveal to you whether the room is in a gravitational field resting on the surface of a planet, or is in space accelerating upward at a constant rate? a. Shine light from one side of the room to the other; the apparent path of the light will be a curve (the path will appear bent) only if you are in the accelerating room, not the one on the planet. b. Throw a ball against the opposite wall of the room; in space the ball will appear to rise whereas on Earth it will remain at the same height above the floor at all times. c. Weigh yourself; you will be weightless if you are in the room that is accelerating upward in space. d. Drop balls and other objects; they will fall to the floor only if you are in a gravitational field. e. There is no known experiment that will reveal which of the two situations you are in.

There is no known experiment that will reveal which of the two situations you are in.

What specific historical event really made it possible for the three laws of planetary motion to be discovered? (Hint: Remember that these are Reading Quizzes reread section 3.1 in your text if you need to!) a. Tycho Brahe died and his assistant was able to get full access to his data. b. Galileo's books were published in Danish and became widely available to the public. c. An alignment of all the known planets in one part of the sky called everyone's attention to them. d. Johannes Kepler came across the complete written works of Aristotle, in which the Greek philosopher had worked out the basics of planetary motion under a heliocentric cosmology. e. A star was seen to explode, creating the famous Crab nebula.

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

The light that allows you to see this very interesting reading quiz is made up of waves. In these waves, the distance between successive crests is called the: a. Wavelength. b. Frequency. c. Velocity. d. crestal longitude. e. Dispersion.

Wavelength.

A hot, glowing lump of coal is taken out of a fireplace. When you look at the glowing coal through a glass prism, the spectrum that you see is a. an absorptionline spectrum. b. an emissionline spectrum. c. a continuous spectrum. d. a brightline spectrum. e. both choices (b) and (d) are correct, since "brightline spectrum" and "emissionline spectrum" are the same thing.

a continuous spectrum.

According to the Einstein's famous formula a. energy can travel much faster than light (in fact, its speed can approach the speed of light squared). b. a little bit of mass can be converted into a substantial quantity of energy. c. mass has to travel at the speed of light before it can produce any energy. d. when two masses collide, a lot of light is always produced. e. Albert Einstein was a tremendous tapdancer.

a little bit of mass can be converted into a substantial quantity of energy.

Many names used by astronomers are misleading or outdated. A good example is the term planetary nebula, which astronomers use to refer to: a. a shell of gas ejected by, and expanding away from, an extremely hot lowmass star that is nearing the end of its life. b. the swirling disk of material out of which planets will form around a young star. c. an entire "cluster" of thousands of stars all close together which, through a small telescope, looks like thousands of individual planets. d. the remains of an exploded highmass star. e. a region of gas and dust in the interstellar medium out of which new stars are forming.

a shell of gas ejected by, and expanding away from, an extremely hot lowmass star that is nearing the end of its life.

For an observer standing today in San Diego (latitude = 30 degrees North), Polaris (also known as the North Star) will always appear a. at no particular position in the sky; it will rise due east and set due west during the course of a night. b. at the observer's zenith. c. is below the observer's horizon at all times. d. about 30 degrees above the observer's northern horizon. e. on the observer's horizon.

about 30 degrees above the observer's northern horizon

Which of the following might be termed a ``black widow pulsar'' by astronomers (hint: Remember that this is a reading quiz!): a. a neutron star that is no longer spinning. b. a mainsequence star that is in orbit around a neutron star. c. a white dwarf that is in the process of collapsing to become a neutron star. d. a white dwarf that is no longer rotating. e. an apparently isolated pulsar that is spinning very rapidly (i.e., more than 500 times per second).

an apparently isolated pulsar that is spinning very rapidly (i.e., more than 500 times per second).

An artist who likes working with sources of light decides to make a modern sculpture out of electrified glass tubes that contain very thin (i.e., not dense) neon gas. When the sculpture is finished, and the electricity is turned on, the tubes glow with a rich red color (just like the neon "gas discharge tube" we looked at in class). What we are seeing is the result of: a. a continuous spectrum. b. an emissionline spectrum. c. a Doppler shift. d. an absorptionline spectrum. e. a Fraunhofer line.

an emissionline spectrum.

An absorptionline spectrum: a. is produced when a thin (i.e., not dense) gas is heated and starts to glow. b. is a continuous "rainbow" of all the colors red, orange, yellow, green, blue, indigo, violet no colors are missing. c. appears as a pattern or series of bright lines, consisting of only certain, specific, colors. d. consists of a series or pattern of dark lines superimposed upon the continuous spectrum of a source. e. is produced by a hot, solid, opaque object, like the filament in a lightbulb.

consists of a series or pattern of dark lines superimposed upon the continuous spectrum of a source.

Professor Leonard claims to have found a mainsequence star onehalf the mass of the Sun that is in the process of collapsing to form a black hole. This would be a. no big deal, since a star with onehalf the Sun's mass always ends up as a black hole. b. unusual, because hardly any stars form with onehalf the Sun's mass. c. impossible, because black holes are only produced when two very massive stars collide. d. impossible, because such a lowmass star would end up as a neutron star. e. extremely surprising, because such a lowmass star would lack sufficiently strong gravity to crush it into a black hole.

extremely surprising, because such a lowmass star would lack sufficiently strong gravity to crush it into a black hole.

The apparent brightnesses of stars in general tells us nothing about their distances (that is, we cannot assume that stars that appear dimmer in our sky are farther away). In order for apparent brightness to be a good indicator of distance, all stars would have to: a. have the same luminosity. b. exhibit exactly the same Doppler shift of its spectral lines. c. have exactly the same radius. d. be at least 100 LY away from us, so that the changing distance from Earth, due to its annual orbit around the Sun, becomes negligible. e. not have any exoplanets in orbit around them.

have the same luminosity.

Interstellar gas consists primarily of a. neon. b. mercury c. oxygen. d. hydrogen. e. iron.

hydrogen.

As we learned in the first class, the Moon is located about 1 lightsecond from the center of the Earth. If the moon were instead located half a lightsecond away from the center of the Earth, the gravitational force exerted on it by the Earth would a. double. b. increase by a factor of four. c. increase by a factor of 30. d. be cut in half. e. remain unchanged

increase by a factor of four.

When four hydrogen nuclei fuse to form a helium nucleus through the "protonproton chain", the mass of the resulting helium nucleus: a. is about 0.7% less than the sum of the masses of the four hydrogen nuclei. b. is about 43% less than the sum of the masses of the four hydrogen nuclei. c. is about 43% greater than the sum of the masses of the four hydrogen nuclei. d. is about 0.7% greater than the sum of the masses of the four hydrogen nuclei. e. None of the above is correct: We all know that matter can neither be created nor destroyed, so the helium nucleus has a mass exactly equal to the sum of the masses of the four hydrogen nuclei.

is about 0.7% less than the sum of the masses of the four hydrogen nuclei.

The theory of gravity that was proposed in 1916 by Albert Einstein is called a. the Big Bang. b. the conservation of angular momentum. c .the general theory of relativity. d. the theory of electromagnetism. e. None of the above answers is correct; while Albert Einstein did many things, he certainly did not come up with an entirely new theory of gravity!

the general theory of relativity.

Kris is falling feet first towards a black hole. As he approaches the event horizon, he feels the lower part of his body (the part closer to the black hole) being pulled more strongly than the upper part of his body (which is further from the black hole). The resulting uncomfortable stretching sensation that he experiences is said to be a direct result of a. gravitational redshift. b. the effects of entering the event horizon. c. gravitational time dilation. d. tidal forces. e. a bad bowl of cereal he ate for breakfast.

tidal forces.