Astronomy assign

Quiz 1

Name: ___________________________________ Section: _____________

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Chapter 8: Jovian Planets 1) Why is Jupiter denser than Saturn? 1)

A) The extra mass of Jupiter compresses its interior to a greater extent than that of Saturn. B) Its core is much larger than Saturn's. C) It has a greater proportion of helium to hydrogen compared to Saturn. D) It is made of a different composition than Saturn, including a higher proportion of hydrogen

compounds and rocks. E) Scientists do not know why this is so.

2) Why is Neptune denser than Saturn? 2) A) The extra mass of Neptune compresses its interior to a greater extent than that of Saturn. B) It has a greater proportion of hydrogen than Saturn. C) It has a different composition than Saturn, including a higher proportion of hydrogen

compounds and rocks. D) Its hydrogen is molecular, whereas Saturn's hydrogen is atomic. E) It is not denser than Saturn.

3) How do the jovian planet interiors differ from one another? 3) A) The core mass decreases with the mass of the planet. B) All have cores of about the same mass, but differ in the amount of surrounding hydrogen and

helium. C) The composition changes from mostly ammonia in Jupiter and Saturn to mostly methane in

Uranus and Neptune. D) The composition changes from mostly hydrogen in Jupiter and Saturn to mostly helium in

Uranus and Neptune. E) All have about the same amount of hydrogen and helium but the proportion of rocks is

greater in those planets closer to the Sun.

4) Why are there no visible impact craters on the surface of Io? 4) A) Any craters that existed have been eroded through the strong winds on Io's surface. B) Its close proximity to Jupiter protects it from impacts. C) They have been covered up by Io's active surface geology. D) It is too small to have been bombarded by planetesimals in the early solar system. E) Io's thick atmosphere obscures the view of the craters.

5) What is the primary reason an icy moon is likely to be more geologically active than a rocky moon of the same size?

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A) Ice has a lower melting point than rock. B) Ice is less rigid than rock. C) Ice is affected by tidal forces to a greater extent than rock. D) Ice contains more radioactive elements than rock. E) Ice is less dense than rock.

Descriptive Astronomy 201 Spring 2019

6) What mechanism is most responsible for generating the internal heat of Io that drives its volcanic activity?

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A) radioactive decay B) bombardment C) accretion D) differentiation E) tidal heating

7) Which of the following statements about Titan is not true? 7) A) Its temperature is too cold for liquid water to exist. B) It is the coldest moon in the solar system. C) It may have oceans of liquid methane. D) Its atmosphere is mostly nitrogen. E) Its surface is hidden from view by its thick atmosphere.

8) Which of the following best describes the composition of the particles forming Saturn's rings? 8) A) hydrogen and helium B) water ice C) volcanic rock D) metallic grains E) methane ice

9) Planetary rings 9) A) are composed of a large number of individual particles that orbit their planet in accord with

Kepler's laws. B) exist around all of the jovian planets. C) orbit in the equatorial plane of their planet. D) all of the above

10) Where is Jupiter's strong magnetic field generated? 10) A) rocky core B) gaseous hydrogen layer C) metallic hydrogen layer D) cloud tops E) liquid hydrogen layer

11) Why do Uranus and Neptune appear blue? 11) A) The methane gas in their atmospheres absorbs all colors except blue. B) The nitrogen gas in their atmospheres absorbs all colors except blue. C) Oceans that are visible through their atmospheres are blue. D) Small dust grains preferentially scatter blue light.

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Chapter 8: Small bodies 12) How do asteroids differ from comets? 12)

A) Asteroids and comets are both made of rocky and icy material, but asteroids are smaller in size than comets.

B) Asteroids are made mostly of icy material. Comets are made of mostly rocky material. C) Asteroids and comets are both made of rocky and icy material, but asteroids are larger in size

than comets. D) Asteroids are made mostly of rocky and/or metallic material. Comets are made mostly of icy

material.

13) What causes the "gaps" observed in the asteroid belt between Mars and Jupiter? 13) A) Jupiter's gravity causes orbital resonances that nudge asteroids out of these areas. B) There are either pure metal or pure rock asteroids, but no mixtures. Thus there is a "gap" in

the composition of asteroids. C) Asteroids cluster together due to their mutual gravity and this creates gaps in their

distribution. D) There are very few asteroids with diameters between 1 and 100 kilometers, creating a gap in

the size distribution. E) There is a large population of asteroids too faint to see called the "gap" asteroids.

14) Why aren't small asteroids spherical in shape? 14) A) Large asteroids were once molten and therefore became spherical, but small asteroids were

never molten. B) The force of gravity in small asteroids is less than the resistance of the rock to deform. C) Small asteroids have odd shapes because they were all chipped off larger objects. D) Large asteroids became spherical because many small collisions chipped off pieces until only

a sphere was left; this did not occur with small asteroids.

15) What is a meteorite? 15) A) a fragment of material from the solar system that has fallen to Earth's surface B) a comet that burns up in Earth's atmosphere C) a streak of light caused by a small particle from space burning up in Earth's atmosphere D) a streak of light caused by a star moving across the sky E) a small moon that orbits one of the giant planets

16) Why does the plasma tail of a comet always point away from the Sun? 16) A) Gases from the comet, heated by the Sun, push the tail away from the Sun. B) The conservation of the angular momentum of the tail keeps it always pointing away from

the Sun. C) The solar wind pushes the plasma ions directly away from the Sun. D) The particles in the plasma tail are more massive than those in the dust tail. E) Radiation pressure from the Sun's light pushes the ions away.

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17) Where did comets that are now in the Oort cloud originally form? 17) A) inside Jupiter's orbit B) outside Neptune's orbit C) near the jovian planets D) within the solar nebula, but far outside the orbit of Pluto E) all of the above

18) How is Pluto's moon system thought to have formed? 18) A) by gravitational capture of passing comets B) by gravitational capture of passing asteroids C) from accretion in a disk surrounding Pluto D) from a giant impact E) by stealing them during a close encounter with Neptune

19) What surprising discovery did the New Horizons spacecraft make during its recent flyby of Pluto? 19) A) Pluto really is a lost moon of Neptune. B) Pluto's surface shows signs of very recent geological activity. C) Pluto has the largest known volcano in the solar system. D) Pluto's surface consists mostly of rocky material. E) all of the above

Chapter 11: The Sun 20) The core of the Sun is 20)

A) at the same temperature but much denser than its surface. B) at the same temperature and density as its surface. C) much hotter and much denser than its surface. D) constantly rising to the surface through convection. E) composed of iron.

21) Sunspots are cooler than the surrounding gas in the photosphere because 21) A) magnetic fields lift material from the sunspot and quickly cool the material. B) strong magnetic fields slow convection and prevent hot plasma from entering the region. C) they are regions where convection carries cooler material downward. D) magnetic fields trap ionized gases that absorb light. E) there is less fusion occurring there.

22) By what process does the Sun generate energy? 22) A) nuclear fusion B) nuclear fission C) gradual expansion D) gravitational contraction E) chemical reactions

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23) Why do sunspots appear dark? 23) A) They are regions that are significantly cooler than the rest of the photosphere. B) They are composed of different elements than the rest of the sun. C) They are regions that do not emit any radiation. D) They are regions nearly devoid of gas.

24) At the center of the Sun, nuclear fusion converts hydrogen into 24) A) hydrogen compounds such as methane. B) radiation and elements such as carbon and nitrogen. C) molecular hydrogen. D) radioactive elements such as uranium and plutonium. E) helium, gamma rays, and neutrinos.

25) How much mass does the Sun lose through nuclear fusion per second? 25) A) 4 million tons B) 600 tons C) 4 tons D) 600 million tons E) None; mass-energy is conserved so the sun cannot be losing mass.

26) The light radiated from the Sun's surface reaches Earth in about 8 minutes. However, the energy of this light was released by fusion in the Sun's core about

26)

A) 11 years ago. B) 8 minutes ago. C) several hundred years ago. D) several thousand years ago.

27) What are coronal holes? 27) A) areas of the corona where magnetic field lines project out into space, allowing charged

particles to escape and form the solar wind B) areas in the corona that allow us to see through to the photosphere C) regions in the photosphere where magnetic lines gather, creating cooler areas with much less

plasma D) tunnels in the outer layers of the Sun that allow photons to escape and form the solar wind E) all of the above

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28) It takes ________ for the sun to progress through one sunspot cycle from a maximum area covered with sunspots, to a minimum, and back to a maximum. Refer to the graph above.

28)

A) about 1 year B) about 110 years C) about 11 years D) This figure cannot be used to answer this question.

29) What observations characterize solar maximum? 29) A) The Sun rotates faster at its poles. B) The Sun becomes much brighter. C) The Sun emits light of longer average wavelength. D) There are many sunspots visible on the surface of the Sun. E) all of the above

30) Which of the following processes is involved in the sunspot cycle? 30) A) the winding up of magnetic field lines inside the Sun due to its differential rotation B) an imbalance in the operation of the solar thermostat C) a slight gravitational contraction of the Sun D) a large change in the amount of visible light emitted by the Sun E) small variations in the rate of nuclear energy generation in the solar interior

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