Astronomy Final Exam

1. The natural object (not one that humans built) in space that's closest to Earth is a. The Moon b. The Sun c. Mars d. Alpha Centauri e. Jupiter

a. The Moon

32. Solar wind particles can be captured by the Earth's magnetosphere. When these particles spiral down along the magnetic field into the atmosphere, they are responsible for: a. aurorae (northern and southern lights) b. tropical storms (regions of rapidly rotating air) c. the greenhouse effect d. the reddish color we see during sunsets

a. aurorae (northern and southern lights)

33. Today we realize that the source of energy for the Sun is a process called a. nuclear fusion b. Kelvin-Helmholtz contraction c. mechanical to thermal energy conversion d. radioactivity

a. nuclear fusion

15. The material that would eventually make all the major bodies in our solar system first gathered together as smaller pieces which astronomers call: a. planetesimals b. nebuloids c. satellites d. differentiated objects e. jovians

a. planetesimals

3. The slow tipping of the Earth's axis in a circle with a period of about 26,000 years is called: a. precession b. ecliptic motion c. retrograde motion d. deferential motion e. revolution

a. precession

11. When a star or galaxy is moving away from us, we observe the Doppler effect by seeing the lines in its spectrum a. red-shifted (shifted toward the red end of the light spectrum) b. blue-shifted (shifted toward the blue or violet end of the light spectrum) c. yellow-shifted (shifted so all the colors become a little bit yellower) d. become darker and darker (like a blackbody)

a. red-shifted (shifted toward the red end of the light spectrum)

35. Why are astronomers much more interested in the luminosity of a star than its apparent brightness? a. because luminosity can be measured exactly, but apparent brightness can only be roughly estimated b. because the luminosity tells us how bright a star really is, while apparent brightness only tells us how bright it happens to look from Earth c. because the luminosity also tells us what elements the star is made of, while apparent brightness cannot tell us a star's chemical make-up d. because luminosity can tell us how bright it is inside the star's core, while apparent brightness only tells us about its outside layers

b. because the luminosity tells us how bright a star really is, while apparent brightness only tells us how bright it happens to look from Earth

24. The rings of the outer planets consist of a. sheets of ice that stretch in round planes millions of miles wide around each planet b. billions of chunks (of various sizes) that all orbit the equator of each planet c. many large moons, about the size of Jupiter's moon Io, all crowded together d. subatomic charged particles, all kept in line by each planet's magnetic field

b. billions of chunks (of various sizes) that all orbit the equator of each planet

16. The average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this? a. solid material hitting the Earth from space heats it up b. carbon dioxide (and other gases) in the atmosphere cause a greenhouse effect c. the rubbing of the continental plates warms up the Earth's surface d. the heat given off by living things makes our planet warmer

b. carbon dioxide (and other gases) in the atmosphere cause a greenhouse effect

26. Short-period comets like Comet Halley a. return to the Oort Cloud during each of their orbits b. come back again and again at predictable intervals c. have a long tail visible during their entire orbit around the Sun d. can never be observed without a telescope

b. come back again and again at predictable intervals

6. To leave the gravitational pull of the Earth, and explore other planets, satellites must have at least: a. circular satellite velocity b. escape velocity c. perigee velocity d. three orbit perturbation

b. escape velocity

28. When a periodic comet leaves its dusty debris behind in its orbit, the Earth can intercept this debris and a. show new impact craters b. have a meteor shower as the dust burns up c. lose ozone from its atmosphere d. speed up the orbit of the Moon

b. have a meteor shower as the dust burns up

4. When it comes to our place in the solar system today, which model do we accept? a. geocentric b. heliocentric c. Ptolemaic d. Aristotelean

b. heliocentric

5. 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 a. eccentricity b. inertia c. action-reaction d. angular momentum

b. inertia

17. The most likely models of the planet Mercury indicate that more than half the planet may be composed of: a. water b. metals c. ammonia and methane ice d. very light and porous rocks e. the element mercury

b. metals

30. When the solar system was forming, the building blocks from which the protoplanets gathered together were the: a. gold, iron, and nickel atoms b. planetesimals (a few km to tens of km wide) c. giant accretion grains about the size of Mars d. extremely hot clouds of gas torn out of the Sun, which was already shining brilliantly e. pure water ice crystals, about the size of a snowflake

b. planetesimals (a few km to tens of km wide)

8. Which of the following is an important part of the reason it is hotter in summer in North America than in winter? a. the Earth is closer to the Sun in summer b. the Sun's rays hit the Earth more directly in the Summer, and spread out less c. the cloud cover over the entire surface of the Earth is much less in summer d. the nights are much longer in summer, allowing temperatures to stabilize e. we see the full Sun in summer, instead of one of its partial phases

b. the Sun's rays hit the Earth more directly in the Summer, and spread out less

20. What allowed the Voyager 2 spacecraft to make a "tour" of all four of the jovian planets in the late 1970's and the 1980's? a. NASA had developed a completely new kind of rocket that could send the craft from planet to planet b. the four planets were approximately aligned on one side of the Sun, and we used the gravity of each planet to speed up the spacecraft to get to the next one in its path c. the spacecraft stopped off to collect fuel on the satellites of each planet before proceeding to the next one d. we used laser beams to propel the spacecraft into the outer solar system, where sunlight is dim

b. the four planets were approximately aligned on one side of the Sun, and we used the gravity of each planet to speed up the spacecraft to get to the next one in its path

31. The Sun's photosphere is a. the central region where the energy of the Sun originates b. the part of the Sun from which the light comes that we see when we look at the Sun with our eyes c. the hottest region of the Sun d. the outermost layers of the Sun's atmosphere e. the first region you would come to when leaving the core

b. the part of the Sun from which the light comes that we see when we look at the Sun with our eyes

19. What is one way that we humans are currently making the atmosphere of the Earth more like that of Venus? a. we are adding more oxygen to the atmosphere by growing more plants and trees b. we are adding carbon dioxide and other greenhouse gases to the atmosphere, which is leading to global warming c. we are setting up a lot of equipment at the north and south poles to cool our planet down d. we have more than doubled the mass of the Earth's atmosphere by making additional air in our factories e. the Earth's atmosphere already resembles the atmosphere of Venus in all ways that are significant

b. we are adding carbon dioxide and other greenhouse gases to the atmosphere, which is leading to global warming

18. Why are there no smaller craters on the surface of Venus, only bigger ones? a. Because Venus is so close to the Sun, the Sun's gravity pulls all smaller chunks of material into the Sun before they can reach Venus b. The seas and lakes of Venus erode away all the smaller craters when they flood c. In Venus' thick atmosphere all smaller chunks of material burn up before they can reach the surface d. Venus is so hot that smaller craters generally melt in the heat, becoming smooth surface

c. In Venus' thick atmosphere all smaller chunks of material burn up before they can reach the surface

29. How can astronomers measure the age of a meteorite that fell from the skies? a. Just like for planets, we measure the age by counting the number of craters on the meteorite b. Meteorites all contain metals and the metal conducts electricity better and better as it ages c. They measure the amount still left of radioactive materials in the meteorite, and how much has turned into decay products d. The age of a meteorite can be found from the angle at which it enters the Earth's atmosphere; so scientists can only get the ages of meteorites they observe falling

c. They measure the amount still left of radioactive materials in the meteorite, and how much has turned into decay products

21. Astronomers believe that Jupiter's strong magnetic field is caused by a. a core of molten iron and nickel b. electric charges from the moon Io c. a huge layer of metallic hydrogen inside Jupiter d. the circulation of large reddish storms containing magnetic ammonia crystals

c. a huge layer of metallic hydrogen inside Jupiter

22. What do astronomers think is the origin of the many irregular moons around the outer planets (irregular meaning they are orbiting backwards and/or have eccentric orbits)? a. These moons were likely formed elsewhere and captured by the giant planets b. These moons are fragments of a much larger moon around each planet that exploded c. These moons were expelled by volcanoes on the surfaces of the giant planets d. These moons had an early interaction with the rings of the giant planets and were moved to strange orbits as a result

c. a huge layer of metallic hydrogen inside Jupiter

34. Which of the following, produced at the core of the Sun, will take the shortest time to emerge from the Sun's photosphere (surface)? a. a photon (wave) of gamma-rays b. a positron c. a neutrino d. a deuteron e. an x-ray produced after radiation has interacted with matter in the core

c. a neutrino

12. The size of the device that collects radiation (such as light) is called a telescope's: a. magnification b. resolution c. aperture d. focal width e. Galilean criterion

c. aperture

27. When a chunk of cosmic material the size of a golf ball or a baseball hits the Earth's atmosphere it makes a a. meteor shower b. radiant c. fireball d. meteorite which breaks into pieces when hitting the ground

c. fireball

14. In radioactive dating, the measure scientists use to note how long (on average) a particular radioactive nucleus will take to decay is called its a. radioactive ratio b. parent-daughter criterion c. half-life d. geological activity

c. half-life

13. During the process of differentiation, a. satellites separate from the parent planets and go into their own orbits b. the faster planets move further out from the Sun c. heavier materials sink to the centers of molten planets d. the atmosphere of a planet changes from oxidized to reduced

c. heavier materials sink to the centers of molten planets

25. A main difference between asteroids and comets is that asteroids are mostly made of rock and comets are mostly made of a. metals b. carbon compounds c. ice d. vapor (gas)

c. ice

2. 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: a. precession b. ecliptic motion c. retrograde motion d. circumpolar motion

c. retrograde motion

9. The period of the moon's rotation on its axis is a. much longer than its revolution around the Earth b. much shorter than its revolution around the Earth c. the same as its revolution around the Earth d. longer or shorter depending on what part of the year we are in

c. the same as its revolution around the Earth

10. The light which allows you to see this very interesting exam is made up of waves. In these waves, the distance between crests is called the: a. frequency b. velocity c. wavelength d. amplitude

c. wavelength

36. Astronomers call the motion of a star across the sky (perpendicular to our line of sight) its a. radial velocity b. Doppler shift c. light travel time d. proper motion e. spectral type

d. proper motion

7. If you want to locate someone precisely on the surface of the Earth, you specify her exact latitude and longitude. If you want to locate a star precisely in the sky, you need to specify its exact: a. meridian and great circle b. constellation c. north and east point d. right ascension and declination e. solstice and equinox

d. right ascension and declination

23. What method was used to discover Pluto in 1929-1930? a. look at irregularities (wobbles) in the motions of Uranus and Neptune b. use one of the first radio telescopes to measure cold radio waves from Pluto c. look for patterns in the orbits of the moons of Neptune to see in which direction Pluto would have escaped d. take pairs of photographs several days apart and "blink" them

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