ASTR 129 FINAL EXAM

Is there a net force for each of the following? Y/N 1. A car coming to a stop 2. A bus speeding up 3. An elevator moving up at constant speed 4. A bicycle going around a curve 5. A moon orbiting Jupiter

1. Yes 2. Yes 3. No 4. Yes 5. Yes

How many tides does one location experience in approximately one day? A. 2 high, 2 low B. 1 high, 1 low C. 1 high or 1 low

A

Suppose you found a star with the same mass as the Sun moving back and forth for a period of 16 months. What could you conclude? A. It has a planet orbiting at less than 1 AU. B. It has a planet orbiting at greater than 1 AU. C. It has a planet orbiting at exactly 1 AU. D. It has a planet, but we do not have enough information to know its orbital distance.

A

The combined mass of all the asteroids in the asteroid belt is A. less than that of any terrestrial planet. B. about the same as that of Earth. C. about twice that of Earth. D. more than that of all the planets combined.

A

What do asteroids and comets have in common? A. Most are unchanged since their formation in the solar nebula. B. They have similar orbital radii. C. They have a similar range of orbital inclinations. D. They have nothing in common with each other.

A

What happened during the accretion phase of the early solar system? A. Atoms and molecules in the gas bonded together and solidified. B. Planetesimals grew by gravitationally attracting material. C. The solar nebula differentiated into metals inside of the frost line and ices beyond. D. Earth gained its oceans from icy planetesimal capture.

A

Where are you on Earth if the Sun never sets on the summer solstice? A. North Pole B. South Pole C. North of the Arctic Circle D. South of the Antarctic Circle

A

Which layer of the Sun do we normally see? A. photosphere B. corona C. chromosphere D. radiation zone

A

A planet is detected via the Doppler technique. The velocity change of the star can tell us about A. the planet's size and density. B. the planet's mass and orbital distance. C. the planet's mass and composition. D. the planet's size and orbital distance.

B

According to the nebular theory, how did the Kuiper belt form? A. It is material left over from the interstellar cloud that never contracted with the rest of the gases to form the solar nebula. B. It is made of planetesimals that formed beyond Neptune's orbit and never accreted to form a planet. C. It is made of planetesimals between the orbits of Mars and Jupiter that never formed into a planet. D. It is made of planetesimals formed in the outer solar system that were flung into distant orbits by encounters with the jovian planets.

B

An asteroid orbits the Sun at an average distance a = 4 AU. How long does it take to orbit the Sun? hint: Remember that p2 = a3 A. 4 years B. 8 years C. 16 years D. 64 years

B

How does the force the Earth exerts on you compare with the force you exert on it? A. Earth exerts a larger force on you. B. You exert a larger force on Earth. C. Earth and you exert equal and opposite forces on each other.

B

Is there gravity acting on an object in orbit? A. Yes B. No

B

On the Moon: A. My weight is the same, my mass is less. B. My weight is less, my mass is the same. C. My weight is more, my mass is the same. D. My weight is more, my mass is less.

B

What is the arrow pointing to in the photo below? A. the zenith B. the north celestial pole C. the celestial equator

B

Where are the Trojan asteroids located? A. surrounding Jupiter B. in the same orbit as Jupiter, at the L4 and L5 Lagrange points C. in the center of the astroid belt D. on orbits that cross Earth's orbit

B

Which of the following statements about comets and asteroids is true? A. Only asteroids collide with Earth. B. Comets are balls of ice and dust. C. Most of the trillions of comets in our solar system have tails. D. All asteroids lie in the asteroid belt between Mars and Jupiter.

B

It's 9 a.m. You look up in the sky and see a moon with half its face bright and half dark. What phase is it? A. first quarter B. waxing gibbous C. third quarter D. half moon

C

The brightest stars in a constellation A. all belong to the same star cluster. B. all lie at about the same distance from Earth. C. may actually be quite far away from each other.

C

The depth of the dip in a star's brightness due to the transit of a planet depends most directly on A. the planet's mass. B. the planet's density. C. the planet's size. D. the eccentricity of the planet's orbit.

C

The ionized gas tail of a comet A. points back along the comet's orbital path. B. points toward Jupiter. C. points toward the Sun. D. points away from the Sun.

C

What is the Sun's energy source? A. primordial heat leftover from the release of gravitational energy when the Sun first formed B. radioactivity C. thermonuclear fusion of H into He in the core D. heat released by gravitational contraction

C

What is the average length of time from one maximum in the number of sunspots on the Sun to the next maximum? A. about 2 months B. 7 years C. 11 years D. 22 years

C

Why are many of the newly detected extrasolar planets called "hot Jupiters?" A. Their masses and composition are similar to what we would expect if Jupiter were hotter. B. The planets tend to be detected around stars that are more massive and hotter than our Sun. C. Their masses are similar to Jupiter but they are very close to the central star and therefore hot. D. Their masses are similar to Jupiter but their composition is similar to Mercury.

C

Of the three ways in which energy is transported in nature (radiation, conduction, convection), which two are important in the Sun? A. radiation and conduction B. convection and conduction C. radiation and convection D. The statement is wrong—all three are equally important in the Sun.

D

One method of estimating the relative ages of the surfaces of planets and moons is based upon the idea that a) Impact craters weather at a known rate, so more weathered craters indicate an older surface. b) Tectonic plates form at a known rate, so fewer plates indicate a younger surface. c) Volcanic activity occurs at a known rate, so fewer volcanoes indicate a younger surface. d) Planets and other bodies are subject to impacts from space at a known rate, so fewer craters indicates a younger surface.

D

The centers of the granular cells on the surface of the Sun are brighter than the edges of the cells because A. the centers are composed of different gases than the edges. B. the centers are cooler than the edges. C. the centers are denser than the edges. D. the centers are hotter than the edges.

D

Where did comets that are now in the Kuiper belt originally form? A. in the asteroid belt B. inside Jupiter's orbit C. near the radius where they orbit today D. in the Oort cloud

D

Why do asteroids and comets differ in composition? A. Asteroids are much larger than comets. B. Comets are much larger than asteroids. C. Asteroids and comets formed at different times. D. Asteroids formed inside the frost line, while comets formed outside.

D

If the Earth rotates once per day, then we in Charleston must be moving at 870 mph in order to be carried around the Earth and brought back to the same spot (relative to the stars) 24 hours later. If we are really moving this fast, why don't we notice it?

Everything around us is moving just as fast

(T/F) Scientists have learned about the Earth's core by drilling very deep holes.

False

If the Earth rotates once per day, then we in Charleston must be moving at 870 mph in order to be carried around the Earth and brought back to the same spot (relative to the stars) 24 hours later. How was it proven that it is the Earth that rotates and not the celestial sphere?

Foucault pendulum

How did Galileo's discovery of the phases of Venus help to disprove the geocentric model?

Galileo observed a full cycle of phases. However, gibbous and full phases of Venus would not be possible in geocentric model.

Why is the Chicxulub Crater important?

Impact that created the Chicxulub crater triggered a worldwide mass extinction event that killed off the dinosaurs.

What are the two conditions necessary for an eclipse to occur?

The sun must be crossing a node, and the moon must be crossing either the same node (solar eclipse) or the other node (lunar eclipse). That means, of course, that solar eclipses can occur only when the moon is new, and lunar eclipses can occur only when the moon is full.

If the Earth rotates once per day, then we in Charleston must be moving at 870 mph in order to be carried around the Earth and brought back to the same spot (relative to the stars) 24 hours later. Why don't we feel it?

We only feel motion when we are accelerating

Evidence of cratering by the impact of massive objects is found a) throughout the solar system. b) only in the inner part of the solar system. c) only in the outer part of the solar system. d) only on the satellites of planets and not on the planets themselves.

a

How would the solar system be different if the solar nebula had cooled, with a temperature half its actual value? a) Jovian planets would have formed closer to Sun. b) There would be no asteroids. c) There would be no comets. d) Terrestrial planets would be larger.

a

Olympus Mons is a a) shield volcano on Mars. b) stratovolcano on Mercury. c) large lava plain on the Moon. d) a cratering site in northern Arizona

a

The Great Red Spot is a) a large, long-lived, high-pressure storm in Jupiter's atmosphere. b) the colored polar cap of Jupiter. c) clouds of dust-laden gas upwelling above the top of a massive volcano on Jupiter's surface. d) a type of storm in Jupiter's atmosphere that can last for a few months before disappearing.

a

The belts and zones of Jupiter are a) alternating bands of rising and falling air at different latitudes. b) cyclonic and anticyclonic storms. c) alternating regions of charged particles in Jupiter's magnetic field. d) the thermosphere and stratosphere, respectively.

a

Which of a planet's fundamental properties has the greatest effect on its level of volcanic and tectonic activity? a) size b) distance from the Sun c) rotation rate

a

Which of the following properties of Venus are very similar to those of Earth? a) Mass and radius and hence average density and surface gravity b) Rotation rate around its axis and hence the length of a solar day c) Surface temperature and atmosphere d) Magnetic field and magnetosphere

a

Astronomers have discovered massive gas giant planets like Jupiter orbiting companion stars at closer than 0.7 AU (about the distance of Venus's orbit). Why don't astronomers believe that these gas giant planets originally formed at these locations? a) The planets' gravity would have been too large to form that close to the star. b) The temperature in the early solar nebula was too high at these distances. c) Their orbital periods are too long for them to be located that close to their companion stars. d) A young star's solar wind would have blown the planets farther away.

b

How did the lunar maria form? a) Large impacts fractured the Moon's lithosphere, allowing lava to fill the impact basins. b) The giant impact that created the Moon left smooth areas that we call the maria. c) The maria are the result of gradual erosion by micrometeorites striking the Moon. d) Volatiles escaping from the Moon's interior heated and eroded the surface in the regions of the maria.

b

What causes synchronous rotation? a) Orbiting bodies are formed out of the same nebula as their planet planet, so they have the same orbital period. b) A massive planet exerts a tidal force on an orbiting body causing it to align such that one side always point toward the planet. c) Orbital resonances with other moons. d) It is just by chance; very few bodies in the solar system exhibit synchronous rotation.

b

What is the Cassini division of Saturn's rings? a) a dark ring, visible from Earth, composed of dark, dusty particles b) a large gap, visible from Earth c) the imaginary circle marking the halfway point of Saturn's rings d) the widest ring of Saturn, located between two large gaps

b

What is the composition of Saturn's rings? a) Particles of methane and ammonia ice b) Water ice or ice-coated rock c) Sodium and sulfur ions d) Small grains of rock

b

Where is most of the water on Mars? a) in its clouds b) in its polar caps and subsurface ground ice c) in deep underground deposits d) in the bottoms of a few craters near the poles

b

Jupiter does not have a large metal core like the Earth. How can it have a magnetic field? a) The magnetic field is leftover from when Jupiter accreted. b) Its magnetic field comes from the Sun. c) It has metallic hydrogen inside, which circulates and makes a magnetic field. d) Its core creates a magnetic field, but it is very weak.

c

Large moons orbit their planets in the same direction as the planet rotates a) rarely. b) about half the time. c) most of the time.

c

The interesting feature of Saturn's rotation is that a) it rotates in a direction opposite to that of most of the planets and opposite to its direction of revolution around the Sun. b) its rotation rate has slowed significantly since it was first observed through telescopes in the 1600s. c) regions at different latitudes rotate at different rates. d) its axis of rotation lies almost in the plane of its orbit.

c

The most common surface features of Venus are a) ancient river valleys and huge floodplains. b) impact craters. c) volcanoes and lava flows. d) evidence of plate tectonic motion, including long mountain ranges and subduction troughs.

c

The rings of Saturn orbit the planet a) as a solid body. b) as five separate solid rings. c) as individual particles, with the inner particles moving fastest. d) as individual particles, with the inner particles moving slowest.

c

What do we conclude if a planet has few impact craters of any size? a) The planet was never bombarded by asteroids or comets. b) Its atmosphere stopped impactors of all sizes. c) Other geological processes have wiped out craters.

c

What's unusual about our Moon? a) It's the only moon that orbits a terrestrial planet. b) It's by far the largest moon in the solar system. c) It's surprisingly large relative to the planet it orbits.

c

Why are there no impact craters on the surface of Io? a) It is too small to have been bombarded by planetesimals in the early solar system. b) Jupiter's strong gravity attracted the planetesimals more strongly than Io and thus none landed on its surface. c) Io did have impact craters but they have all been covered over by volcanic activity. d) Any craters that existed have been eroded through the strong winds on Io's surface.

c

The central cores of Jupiter and Saturn are thought to be composed of a) methane, ammonia, and water ice. b) liquid metallic hydrogen. c) magnetized iron. d) rock.

d

The surface of Europa appears to be covered with a) dark areas of older crust separated by lighter, grooved terrain. b) many ancient craters and maria. c) rugged mountain ranges and ancient volcanoes. d) a smooth layer of ice, crossed by many cracks.

d

Which of the following does not have a major effect in shaping planetary surfaces? a) impact cratering b) volcanism c) erosion d) magnetism

d

Which of these facts is NOT explained by the nebular theory? a) There are two main types of planets: terrestrial and jovian. b) Planets orbit in same direction and plane. c) Existence of asteroids and comets. d) Number of planets of each type (four terrestrial and four jovian).

d

What is necessary for differentiation to occur in a planet? a) It must have metal and rock in it. b) It must be a mix of materials of different density. c) Material inside must be able to flow. d) All of the above e) b and c

e