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University of Mississippi
ASTR 103, First Summer Session 2008

Test 2

Circle the letter next to your choice of answer for each multiple-choice question (do not write the letter next to the question). Write no more than three lines for each short-answer question (one or two lines are often sufficient).

(1) Does the Sun rotate?
a. Yes, it makes one full rotation every 8 minutes.
b. Yes, once every 27 days approximately (at the equator).
c. Yes, once every 365 days (so the same side always faces us).
d. No, but we see different parts of it because we orbit around it.

(2) Can asteroids be seen with the naked eye?
a. Yes, they look as bright as planets but they move faster.
b. Yes, they look like some of fainter stars.
c. Only the four brightest asteroids can be seen.
d. No, they are all way too dim.

(3) What does Jupiter look like?
a. A rocky ball with volcanic and meteorite craters.
b. A smooth ice ball with cracks caused by internal activity.
c. An orange-brown gas ball with cloud bands and turbulence patterns.
d. A blue-green gas ball with a few weather patterns and dark spots.

(4) How does the far side of the Moon differ from the one we see?
a. It is older and more cratered, and has almost no "maria".
b. It is almost completely smooth, with fewer craters.
c. It is covered in ice because it never sees the sunlight.
d. It is not that different, on average it looks about the same.

(5) Which of these does Neptune most resemble, in terms of appearance and size?
a. Venus.
b. Jupiter.
c. Uranus.
d. Pluto.

(6) To what extent have we explored Pluto?
a. Pluto is too far for NASA to consider sending a spacecraft there.
b. Spacecraft from Earth have flown by Pluto a few years ago.
c. A spacecraft from Earth is orbiting Pluto right now.
d. A spacecraft is on its way to Pluto and will arrive in a few years.

(7) How big is the radius of Venus compared to the Earth's?
a. About 1/4 the size.
b. About 95% the size.
c. About twice the size.
d. About 10 times the size.

(8) Does any meteoroid ever enter the Earth's atmosphere?
a. So far not, we have been lucky; any meteoroid would cause major destruction.
b. No, all meteoroids disappeared millions of years ago.
c. An occasional one does every few years, but they all burn up before reaching the ground.
d. Yes, every day, and some of the larger ones end up on the surface as meteorites.

(9) Why are most asteroids not round like planets are?
a. Because they have suffered many more collisions.
b. Their gravity is not strong enough to make them round.
c. They are irregularly shaped pieces of a planet that broke up.
d. Because they don't rotate as fast as planets do.

(10) What was the Tunguska event?
a. The impact of a large asteroid that killed the dinosaurs 65 million years ago.
b. A comet or asteroid that reached Earth in 1908, flattening a large area in Siberia.
c. One of the brightest meteor showers in recorded history, which happened in 1833.
d. The largest gathering of meteor watchers ever, that drew a crowd of 40,000 people.

(11) Which of the following planets looks most like the Moon?
a. Mercury.
b. Venus.
c. Earth.
d. Mars.

(12) What effect has the moon Mimas had on Saturn's rings?
a. Its resonance with ring particles produces the gap called the Cassini division.
b. It collides with ring particles and prevents them from extending further out.
c. Its orbit crosses the rings and produces holes in them when Mimas goes through.
d. The rings were produced when Mimas broke up long ago into small fragments.

(13) How big is the Great Red Spot on Jupiter?
a. About the size of a large city.
b. About 200 miles across.
c. Bigger than the whole Earth.
d. Bigger than the whole planet Saturn.

(14) How many known moons does Pluto have?
a. None, it is too small to have a moon. b. One.
c. Three. d. 12.

(15) To what extent have our spacecraft explored Mercury?
a. No spacecraft has even been in that part of the Solar System.
b. So far it has only been visited and photographed during spacecraft flybys.
c. Some of the Mariner spacecraft landed on its surface and sent pictures.
d. One of the Apollo missions took three astronauts there.

(16) How large is Mars compared to Earth, in terms of its radius?
a. About half the size.
b. About 95% the size.
c. About twice the size.
d. About 5 times the size.

(17) What is the Kuiper belt?
a. A ring found around an impact crater on the surface of an asteroid.
b. The region around a planet inside which tidal forces are strongest.
c. One of the gaps in the asteroid belt produced by resonances with Jupiter.
d. The region of the Solar System beyond Neptune where Pluto is located.

(18) What are the best times for viewing Mercury from Earth with the naked eye?
a. In the middle of the day, around noon.
b. In the middle of the night, close to midnight.
c. Right before dawn or after sunset.
d. Mercury cannot be seen with the naked eye.

(19) What is interesting about Jupiter's moon Europa?
a. The active volcanoes on its surface.
b. The probable existence of water below its icy surface.
c. A very large chunk of its surface is missing, possibly from a collision.
d. It is the fastest spinning moon in the solar system.

(20) In what direction does the tail of a comet point?
a. Backwards, away from the direction in which the comet moves.
b. Away from the Sun, because it is pushed away by the solar wind.
c. Toward the Sun, because it is attracted by its gravity.
d. Toward the Lagrange point of Jupiter's orbit.

(21) What is the corona?
a. The part of the Sun's interior that surrounds the core.
b. A layer just below the Sun's surface, sometimes visible through a sunspot.
c. The thin, extended, outermost layer of the Sun's atmosphere.
d. A large black spot located near the Sun's North pole.

(22) How far is Saturn from the Sun?
a. About twice as far as the Earth is.
b. About 10 times as far as the Earth is.
c. About 40 times as far as the Earth is.
d. About 200 times as far as the Earth is.

(23) Why can a comet have more than one tail?
a. One is made of gas (ions), the other of dust particles.
b. Each time the comet comes near the Sun, it may get a new tail.
c. If the comet swings by a planet and is deflected, it gets a new tail.
d. Because it can break up, and each piece will have its own tail.

(24) How is energy produced in the Sun?
a. Nuclear reactions in the core.
b. Chemical reactions in the radiation zone.
c. Magnetic fields in the convection zone.
d. Gravity from the black hole at the center.

(25) What is unusual about Uranus' rotation?
a. Uranus is the only planet that doesn't rotate at all.
b. It is the fastest rotation of all planets in the solar system.
c. It has changed direction several times since we started observing it.
d. The axis is tilted about 90 degrees, almost in the plane of the orbit.

(26) Where did the planet Mars get its name from?
a. It is the fourth planet, and Mars was ranked fourth among ancient gods.
b. The reddish color of the planet, always considered as the color of love.
c. It is the fourth planet, and both the Greek name Aris and Mars have four letters.
d. The reddish color of the planet, associated with the god of war.

(27) What is the Roche limit?
a. The distance from a planet inside which a moon can be broken apart.
b. The maximum number of moons a planet can have.
c. The smallest size a moon can have for it to orbit around a planet.
d. The edge of the solar system, beyond which no planets can exist.

(28) How many moons does Mars have?
a. None.
b. One.
c. Two.
d. Four.

(29) What is special about Saturn's moon Titan?
a. It has a thick atmosphere and cloud cover.
b. There are active volcanoes on its surface.
c. It is the only moon entirely made of gas.
d. There is liquid water under its icy surface.

(30) Why is Venus so bright in the sky?
a. Its surface is so hot that it glows from the thermal radiation it emits.
b. It is large, relatively close, and its thick cloud cover is very reflective.
c. Its atmosphere produces light from constant thunderstorms and lightning.
d. It is the largest planet in the solar system.

(31) In magnified pictures of the Sun, the surface appears covered with "granules". What are they?

(32) Describe briefly one aspect of what you would feel or what you would see if you were on the surface of Venus.

(33) According to the leading theory, how was the Moon formed?

(34) Do we have spacecraft currently sending data from Mars, either on the surface or in orbit around it?

(35) Have spacecraft from Earth visited any asteroid?

(36) Jupiter has a "differential rotation". What does this mean?

(37) What are Saturn's rings made of?

(38) Why isn't Pluto's officially called a planet anymore?

(39) Name one difference between asteroids and comets.

(40) What are "shooting stars"?