PTYS/ASTR 206 -- Section 2 -- Spring 2006 Final Exam: 5/9/06 (Page 1/8)
NAME:_________________________________________________________________
Part 1: Short Answer (please fill out the answers in the space provided; do not mark the scantron sheet for this part!). Short-answer questions are worth 4 pts each.
#1. Name three key properties of the planets in general that must be explained in any successful scientific theory of the formation of the solar system. At least one property should relate to the orbits of the planets, and at least one should relate to the physical properties or elemental compositions of the planets. (The third property can be from either category)
#2. What is liquid metallic hydrogen, and what is its significance to Jupiter and Saturn?
#3. Explain the difference between an asteroid, a meteor, and a meteorite.
#4. Briefly explain how Neptune was discovered.
#5. What is the best explanation for the occurrence of annually recurrent meteor showers such as the Leonids and Perseids?
#6. Draw two diagrams of the Sun-Earth-Moon system: one during new moon and one during full moon. In addition, explain why eclipses of the Sun or Moon do not occur every time the Moon is at either phase, even though your diagrams will presumably suggest that this occurs. Be sure to label your diagrams clearly!
Part 2: Multiple Choice
Mark the appropriate answer in the appropriate place (i.e. in numbers 1-40) on the scantron sheet. Use a number 2 pencil. Be sure to write your name and fill in the ovals, in the upper left. Multiple-choice questions are worth 2 pts each.
#1. What is a distinguishing feature about Jupiter’s moon Io?
A) possible lakes of liquid ethane and methane on its surface
B) vast underground liquid water ocean
C) geysers of liquid water erupting out of cracks on its surface
D) extremely active volcanism driven by tidal forces
#2. Which of the following can be said to be similar to the Cassini division of Saturn’s rings in terms of how the feature formed?
A) The Trojan asteroids
B) The Kuiper belt
C) The Kirkwood gaps
D) The Oort cloud
#3. A typical comet has a composition that is most similar to that of
A) The Moon
B) Pluto
C) A meteorite
D) An asteroid
#4. Assume you are an astronomer that is observing the occultation of a star by a planet. You observe that the light from the star periodically dims unexpectedly before and after the planet itself passes in front of the star. Which of the following theories best explains the observation?
A) The planet has a network of large satellites
B) The planet has an extensive upper atmosphere
C) The planet has a very strong magnetic field
D) The planet has a ring system
#5. What is the physical appearance of Jupiter as seen from Earth or a spacecraft?
A) a series of dark belts and light zones parallel to the equator
B) a uniform bluish color with a high-level haze
C) v-shaped cloud forms around the equator, indicative of rapid winds
D) uniform red-colored dust clouds over cratered surface
#6. Which moon of Saturn was recently discovered to have liquid water geysers erupting on its surface?
A) Titan
B) Enceladus
C) Iapetus
D) Charon
#7. Which object below can never be seen with the naked eye (i.e. without using a telescope)?
A) Mars
B) Uranus
C) Neptune
D) Mercury
#8. The first quarter moon rises at _____ and is highest in the sky at ____.
A) sunset, sunrise
B) noon, sunset
C) midnight, sunset
D) sunset, midnight
#9. Who discovered Uranus?
A) We are not certain, it has been known as a planet since ancient times
B) William Herschel
C) Galileo Galilei
D) Tycho Brahe
#10. What two factors account for the strong magnetic fields of Jupiter and Saturn?
A) rapid rotation and electrically conducting interiors
B) strong convection and iron-rich surfaces.
C) atmospheric storms and large mass
D) rapid rotation and strong tidal forces
#11. The inner planets formed
A) when the Sun’s heat destroyed all the smaller bodies in the solar system
B) in the outer solar system and then were deflected inward by interactions with Jupiter
C) by collisions and mergers with planetesimals
D) when a larger planet broke into pieces.
#12. The discovery of a moon orbiting a planet allows astronomers to measure
A) The planet’s mass
B) the moon’s mass and density
C) the planet’s ring structure
D) the planet’s cratering history
#13. A moon placed at a planet’s Roche limit will
A) change color
B) break into smaller pieces.
C) develop a magnetic field
D) flatten into a disk.
#14. Which of the following is true according to Kepler’s Third Law of planetary motion?
A) The smaller the orbit, the longer it takes for the planet to complete one revolution.
B) The smaller the radius of a planet, the more rapidly it rotates on its axis.
C) The larger the orbit, the longer it takes for the planet to complete one revolution.
D) The time to complete one revolution of its orbit depends on the size of the planet itself. This is why the Jovian planets take so long to revolve around the Sun … because they’re so large.
#15. What does Uranus look like from space (in visible light)?
A) perpetually covered with yellowish, sulfur-rich clouds
B) blue-green and featureless
C) blue-green with white, high-altitude clouds, and dark storms
D) reddish belts and light zones, parallel to the equator
#16. Which of the following is the best theory for the formation of our Moon?
A) The Moon and Earth both formed at the same time from the solar nebula, and the Moon just went into orbit around the Earth.
B) A Mars-sized object impacted the primordial Earth, and the Moon formed from the debris.
C) The Moon was a Kuiper-Belt object that was sent into the inner solar system. The Earth then captured the Moon as it was passing by.
D) The primordial Earth rotated rapidly enough so that a globule of molten material “spun off” from the Earth and formed the Moon.
#17. Which of the following objects would you expect to have its orbit be entirely between Mars and Jupiter?
A) a main-belt asteroid
B) a Kuiper-belt object
C) an intermediate-period comet
D) a Plutino
#18. What is one piece of evidence that would suggest that a moon is a captured asteroid?
A) It is heavily cratered
B) It orbit is nearly aligned with the planet’s equator
C) It has a retrograde orbit about its parent planet
D) Its has a prograde orbit about its parent planet
#19. The equatorial diameter of Jupiter is about 6% larger than the polar diameter of Jupiter. Why?
A) beneath the clouds, Jupiter has many equatorial mountain ranges
B) Jupiter is distorted by tides due to its satellites
C) Jupiter rotates rapidly.
D) solar tides have distorted Jupiter.
#20. Which of the following best describes the surface of Europa?
A) icy surface that is overlain with ridges, fractures, and cycloid features
B) icy surface that is saturated with numerous impact craters
C) rocky surface that has both ridges and craters
D) rocky and icy surface with numerous volcanoes and geysers
#21. What are Trojan asteroids?
A) Asteroids in one of the Kirkwood gaps
B) Rocks thrown onto the field by boisterous USC fans
C) Asteroids that collect in two of Jupiter’s Lagrange points, near Jupiter’s orbit
D) Asteroids in orbit about Saturn that help form its rings
#22. How do comets that come from the Kuiper belt differ from those that come from the Oort cloud?
A) They have more elliptical orbits
B) Their orbits are not as inclined with respect to the ecliptic plane
C) They do not form dust tails
D) The process of naming them is different.
#23. What peculiar feature accompanies Io in its orbit around Jupiter?
A) a torus or ring of ionized sulfur, oxygen, atoms, and electrons that are probably related to powerful aurora on Jupiter
B) a small Sheppard satellite that shares Io’s orbit
C) a comet-like tail of rocks and dust, shining by reflected sunlight
D) a narrow ring of rocks and dust (Jupiter's ring) at about Io's orbital distance
#24. Which of the following best describes a comet’s tail?
A) always points away from the Earth
B) always points in the direction in which the comet is headed
C) always points in the direction in which the comet originated from (i.e. leaves a trail)
D) always points away from the Sun
#25. What is the primary energy source for the Great Red Spot and the Jovian atmosphere?
A) incoming solar radiation
B) heat generated by the decay of radioactive elements inside Jupiter
C) primordial heat that still exists inside Jupiter left over from its formation
D) thermonuclear fusion occurring in Jupiter’s core
#26. What can be said about water on Mars?
A) there is strong evidence that liquid water exists on Mars today
B) there is strong evidence that liquid water once existed on Mars, and exists as ice beneath its surface today.
C) there is no water on Mars in any form
D) the only evidence of water comes from the Earth-based observations of canals, which has proven to be wrong
#27. Why is it best to observe a planetary body from Earth when it is at opposition?
A) It is closest to the Sun, making it brighter than normal
B) It is highest in the sky just as the Sun rises, making it easiest to see
C) It is easiest to spot in the night sky by using the Moon as a guide
D) It is closest to the Earth, making it appear both larger and brighter than usual
#28. Which planet is characterized by a blue-green appearance, with dark storms and white, high-altitude clouds of frozen methane crystals?
A) Neptune
B) Mars
C) Uranus
D) Earth
#29. What is the most common type of meteorite?
A) stony
B) stony iron
C) carbonaceous chondrites
D) iron
#30. The composition of the atmosphere of Titan, a satellite of Saturn, is mostly.
A) methane with small quantities of other gases.
B) nitrogen, methane, and other hydrocarbons.
C) carbon dioxide with small quantities of other gases.
D) methane, ammonia, and water vapor.
#31. Carbon dioxide gas constitutes less than 1% of the Earth’s atmosphere, yet it is very important to determining the surface temperature of the Earth. Why?
A) it blocks visible radiation reflected off of Earth’s surface, thereby heating the atmosphere and surface
B) it blocks infrared radiation emitted by Earth’s surface, thereby heating the surface
C) it destroys ozone that allows more sunlight to enter the Earth and heat the surface
D) it blocks infrared radiation entering Earth’s atmosphere, creating cosmic-ray air showers that significantly cool the atmosphere
#32. Which meteorites are believed to be samples of primordial solar nebula material?
A) stony-iron meteorites
B) iron meteorites
C) meteorites showing Widmanstätten patterns when etched with acid
D) carbonaceous chondrites
#33. The comet Shoemaker-Levy 9
A) was responsible for the extinction of the dinosaurs nearly 65 millions years ago
B) left a chain of craters on the surface of Ganymede
C) impacted Jupiter and left behind dark “scars” in its atmosphere
D) was captured by Jupiter and is still orbiting around the planet today
#34. An orbital resonance
A) is where a planet orbits around the Sun in a manner where enormous tides are raised on the planet, causing the planet to fracture and possibly break up
B) is where the periods of two orbiting bodies can be expressed as a simple integer ratio.
C) is where the physical radii of two satellites (both in orbit about a single parent body) are 2:1 or 3:2.
D) is what causes the Moon to always show the same face towards the Earth
#35. Titan’s surface probably had lakes of liquid ethane or methane in the recent past, even though it is very far from the Sun and quite cold. How can this be, i.e. why isn’t it frozen?
A) It has a very strong internal heat source
B) It is very close to Saturn, which warms it up.
C) Even though it is cold, Titan has a thick atmosphere that provides a high surface pressure, and ethane and methane can exist as liquids under these conditions
D) Ethane and methane can only exist as liquids.
#36. What are the zonal winds on Jupiter?
A) winds blowing horizontally northward and southward in the cloud layer
B) winds blowing vertically upward and downward in regions of strong convection
C) winds blowing horizontally in a circular pattern, such as around the Great Red Spot
D) winds blowing horizontally eastward and westward in the cloud layer
#37. How is Titan similar to our Moon?
A) Both have an atmosphere
B) Both are in synchronous rotation about their parent body
C) Both are heavily cratered
D) Both have a strong magnetic field
#38. The particles in Saturn's rings
A) move in circular orbits, with the outer particles moving fastest because they are farthest from the planet
B) all move as if they are one solid disk
C) revolve in different directions depending on the distance from the planet
D) move in circular Keplerian orbits, the inner particles moving fastest
#39. (2 pts. extra credit) What is a cosmic ray?
A) A particle produced in the center of the Sun that interacts very little with matter
B) Remnants of the solar nebula that occasionally enter Earth’s atmosphere creating a meteor shower
C) A photon that is emitted as blackbody radiation from the cold universe
D) A very high-energy charged particle, probably accelerated by a shock wave associated with a supernovae explosion.
#40. (2 pts extra credit) Suppose that somewhere in a galaxy far, far away, explorers come across a planetary system and find a terrestrial planet that is somewhat larger than Earth, but receives somewhat less sunlight from its parent star than Earth receives from the Sun. What do you expect this planet to look like?
A) It may be quite similar to Earth in that it should have a thick atmosphere and very few craters on its surface
B) It is probably very different from Earth in that it will have little or no atmosphere and many craters
C) It is likely to have a thick atmosphere, and many large craters
D) It is likely to have an atmosphere composed mostly of oxygen. No way to infer how cratered its surface is.