PY124: Solar System Astronomy
SAMPLE TEST 3
Instructor: R.A. Egler
About this sample test:
The sample tests are intended to acquaint you with the types of questions I will ask, along with the manner that I will ask them. Although some questions on the actual test may be similar, they will not be identical. Of course, if you still have trouble, stop by my office and we'll go over the questions that are giving you a problem.
Each Question is Worth 4 Points (25 questions = 100 points)
Choose the best answer to each question and mark that answer on the answer sheet.
1) Of A, B, and C below, which is NOT a true statement about comets? (If
A, B, and C are all true, then D is the answer.)
A) Comets always orbit the sun in the same direction as the planets orbit.
B) A comet's tail always points away from the sun.
C) Kepler's laws describe the orbits of comets.
D) All of the above are true.
2) The fact that the moons of Uranus lie in the planet's equatorial plane
are an indication that
A) they formed after the planet was
tilted.
B) the are captured asteroids.
C) they were tilted at the same time
that the planet was tilted.
D) they are held by a strong
magnetic field.
3) The rings of Jupiter were first discovered
A) by a passing spacecraft (Voyager).
B) by our intrepid hero, Spaceman Spiff (from Calvin and Hobbs).
C) by direct telescopic observation (they were seen with a telescope) by Galileo.
D) by observation from the Earth of a stellar occultation.
4) The rings of Saturn were shown not to be solid by astronomers at the
Allegheny Observatory (University of Pittsburgh) in about 1885. Spectra were
taken of the inner and outer edges of the rings. These spectra showed, by
analysis of the redshift and blueshift,
A) that the inner edges of the rings orbited faster than the outer edges.
B) that the outer edges of the rings orbited faster than the inner edges.
C) that the outer edges and the inner edges orbited at speeds consistent with the rings being solid, but that the edges were made of completely different materials.
5) Why don't the rings of those planets that have rings like Saturn
condense to form one or two large moons?
A) The material in the rings lies within the Roche limit, and so is prevented from existing as a large body by gravitational forces.
B) The material is orbiting too fast to condense into one or two large bodies.
C) There is not enough material in the rings to form a large body.
6) Which of the following statements concerning Jupiter and Saturn is false?
A) They both have a ring or rings.
B) They are both gas giants.
C) Jupiter was known in antiquity, but Saturn wasn't discovered until the late 19th century.
D) They both have "years" that are longer than that of Mars.
7) The icy surface of Europa is largely free of craters compared to many
other moons. This fact likely
points to what?
A) Europa's gravity is considerably
weaker than that of the other Galilean moons.
B) A strong electrical current
between Europa and Jupiter.
C) Europa having an internal source
of heat.
D) There is no known mechanism to
account of the lack of craters on Europa.
8) Which of the following was the first planet predicted to exist
before it was found, based on perturbations of another planet's orbit ?
A) The planet orbiting 51 Pegasi
B) Neptune
C) Uranus
D) Pluto
9) Periodic meteor showers (ones which reoccur each year) such as the
Leonid or the Draconid meteor showers are the result of
A) the Earth passing through the Kuiper belt each year.
B) small asteroids that have their normal orbital paths altered by the gravity of Jupiter at the same point each year.
C) bits of material that hit the Earth as it passes through the orbital path of a periodic comet.
D) debris that was expelled into interstellar space by a star that exploded millions of years ago in whatever constellation the showers are named for.
10) Mercury and Titan are close in size, but Mercury has no atmosphere,
and Titan has a substantial atmosphere. Why is Titan able to hold a more
substantial atmosphere than Mercury?
A) Because Titan has much higher gravity than Mercury.
B) Because Titan is farther from the sun than Mercury, and thus receives far less energy from the sun. This results in lower speed for the molecules in the atmosphere of Titan than for Mercury, so more of an atmosphere can stay with Titan.
C) Because Titan's atmosphere is composed of very thick, viscous semi-liquid gasses that actually stick to Titan, rather like molasses, where Mercury's ancient atmosphere was only light gasses that escaped quickly.
D) Because Titan orbits such a large planet (Saturn), and thus the gravity of the planet makes it easier for Titan to keep an atmosphere, but Mercury is a planet all by itself.
11) Our search for planets around other stars (extrasolar planets) has so
far yielded relatively large, Jupiter-like planets, which orbit mostly fairly
close to their stars. Does this mean that Earth-sized and smaller planets are
rare?
A) No, although we've been unable to actually see these smaller planets, we've seen their shadows pass across the disk of their "sun", so we know that they're out there, waiting to be discovered.
B) No, the methods we use to search for extrasolar planets are more likely to detect large planets which orbit close to their star, so its not surprising that this is what we have found.
C) Yes, if there were Earth-sized planets orbiting these stars we would easily be able to detect them.
D) Yes, we've been able to detect traces of elements in the atmospheres of the large extrasolar planets that indicate that these large planets have absorbed the smaller planets. We are just lucky that a similar thing didn't happen here.
12) The "Great Red Spot" on Jupiter is similar to other spots
on several of the Jovian planets. These spots can be partly explained by the
coriolis force. Applying the principle of the coriolis force, we would expect
that as an object in the atmosphere
A) moves away from the equator, either north or south, that it would appear to move faster than the ground under it.
B) moves toward the equator, from either the north or the south, that it would appear to move faster than the ground under it.
C) moves away from the equator, going north , that it would appear to move faster than the ground under it, and going south, it would appear to move slower than the ground under it.
D) moves away from the equator, going north, that it would appear to move slower than the ground under it, and going south, it would appear to move faster than the ground under it.
13) Consider an object in space that hits the Earth's atmosphere and
continues down to strike the surface. What names do we assign to the object in
each of its phases, in order (in space, in the atmosphere, on the ground)?
A) asteroid in space; meteor in the atmosphere; meteoroid on the ground
B) meteoroid in space; meteorite in the atmosphere; meteor on the ground
C) meteor in space; meteoroid in the atmosphere; meteor on the ground
D) meteoroid in space; meteor in the atmosphere; meteorite on the ground
14) Which of the Jovian planets has retrograde rotation?
A) Jupiter
B) Saturn
C) Uranus
D) Neptune
15) There are no asteroids at the Jupiter's L1, L2, and L3 points, even
though the Trojan asteroids orbit at the L4 and L5 points. Why is this?
A) Most likely no asteroids have ever wandered into the L1, L2, and L3 points, because if some did, they would be "stuck" in orbit there.
B) The L1, L2, and L3 points are unstable. Any asteroids that were once in them would have drifted out over a short period of time due to perturbations from other bodies.
C) The L1, L2, and L3 points lie within Jupiter's Roche limit, L4 and L5 do not.
D) The L1, L2, and L3 points are all contained in Jupiter's ring.
16) The Kirkwood gaps in the asteroid belt
A) are at random orbital distances, and their cause is not well understood.
B) are caused by the gravitation of Jupiter, and all at integer resonances with Jupiter's orbit (like 1:2, 1:3 2:3, 3:5 and so on)
C) are the result of collisions between asteroids, which are more likely in certain orbits, and which sweep out certain gaps in the asteroid belt.
D) are the result of comets passing through the asteroid belt.
17) The volume of Jupiter is about 1400 times that of the Earth, yet we
determine the mass of Jupiter to be only about 318 times the mass of the Earth.
What does this tell us about Jupiter?
A) Jupiter is made of materials that are less dense than those making up the Earth.
B) We have miscalculated either the volume or the mass of Jupiter.
C) Jupiter is most likely made up of materials like the Earth, since we would expect mass to increase more slowly than volume for any material.
D) Jupiter is made of materials that are more dense than those making up the Earth.
18) One method that we use to date the surface of the Galilean moons is:
A) radioactive dating of samples of the surfaces.
B) counting the number of craters per square kilometer combined with an estimate of the rate of impacts on the surfaces.
C) comparing the distance at which the moons orbit Jupiter and using Kepler's Laws.
D) All of the above
19) The most common element in the solar system is:
A) Hydrogen
B) Methane
C) Helium
D) Ammonia
20) We find that the smaller moons of the Jovian planets tend to be irregular
shapes, not spherical, while the larger moons are spherical. Is there a reason
why we might expect this to be true?
A) No, there is no particular reason to expect small bodies to be irregularly shaped.
B) Yes, we would expect them to be irregularly shaped due to their extreme distance from the sun.
C) Yes, we would expect them to be irregularly shaped because they are too small for their own gravity to "mush" them into spheres.
D) Yes, we would expect them to be irregular due to the greater tidal effects of the large Jovian planets on the smaller moons.
21) The layer of the sun that produces most of the visible light is:
A) the chromosphere.
B) the photosphere.
C) the corona.
D) the convection zone.
22) The sun gets its energy main from
A) the fission of helium to hydrogen.
B) the fusion of uranium into plutonium.
C) the fusion of hydrogen into helium.
D) burning coal.
23) The sun's magnetic field reverses polarity on a fairly regular
basis. What is the average time
between magnetic pole reversals? (Flipping from N-S to S-N)
A) 5.5 years
B) 16.5 years
C) 22 years
D) 11 years
24) The average period of Halley's comet is about 76 years, which makes
it a short period comet. Short period
comets come primarily from which region of the solar system?
A) The Kuiper Belt.
B) The Oort Cloud.
C) The Asteroid Belt.
D) The Trojan Asteroids.
25) We can precisely measure the positions of stars with possible
planetary systems over time to search for extrasolar planetary systems because:
A) Large planets will cause the star to wobble slightly.
B) Stars with planets remain at precisely the same location as the planets orbit, due to the constant slight pulling in different directions caused by the planets' gravity
C) None of the above. Measuring the positions of stars cannot possibly give us information whether they have planets.
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