Ast ch 14 and 15 – Flashcards
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The orbits of most asteroids
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Lie entirely beyond the orbit of Mars
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The NASA orbit that ultimately landed on the surface of the asteroid Eros was
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Near Shoemaker
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About what percent of all asteroids are C-Type?
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75%
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About what percent of all asteroids are S-type?
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15%
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What is the typical size of most known asteroids?
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A few kilometers
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What are Dactyle, Gaspra, Mathilde, Eros, and Ida?
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The only four asteroids explored by spacecraft to date
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What is the defining property of the Trojan asteroids?
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They have orbits at the distance of Jupiter and 60 degrees ahead of or behind it
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The orbital resonances with Jupiter are shown in the
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Kirkwood Gaps
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The type of asteroid that would appear darkest and reflect the least light is type
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C
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The type of asteroid that would be the densest would be
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M
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The three largest asteroids are
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Ceres, Pallas, and Vesta
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On its way to Jupiter, Galileo also gave us close-ups of
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Gaspra and Ida
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Before it arrived in orbit about Eros, the NEAR spacecraft also flew past
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Asteroid Mathilde
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The Trojan asteroids have orbits that
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Stay 60 degrees ahead of or behind Jupiter
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The Amor asteroids have orbits that
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Cross the orbit or Mars, but not Earth, at perihelion
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Asteroid 2004 FH passed within a tenth of the Earth-Moon distance in March 2004. When its period was found to be about nine months, it was classified as an
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Aten Asteroid
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Compared to Ida, Eros and Gaspra, what was odd about Mathilde?
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It was less dense than rock, but more than ice, suggesting a porous structure
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The Apollo and Aten asteroids have orbits that
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Cross the orbit of Earth at perihelion
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Which of the following objects never collide with the Earth?
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Amor asteroids
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The major impact in the Yucatan wiped out the dinosaurs about:
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65 million years ago
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The first hint of the role of asteroids in extinction of the dinosaurs came from
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Finding a layer of worldwide iridium enriched dust
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The Kirkwood Gaps in the asteroid belt are due to resonances with Jupiter
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True
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Most asteroids are differentiated, as reflected by their spherical shapes
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False
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All known asteroids can be found in the asteroid belt
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False
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Eros is the only asteroid upon which a spacecraft has landed
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True
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Discovered by the spacecraft Galileo, Dactyl is a satellite of larger Ida.
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True
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The asteroid Vesta seems to have once been volcanicly active, amazing for its small size
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True
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About a trillion comets are thought to be located far, far beyond Pluto in the
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Oort cloud
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The bright spherical part of a comet observed when it is close to the Sun is the
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Coma
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A comet's _________ stretches directly away from the sun
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Plasma tail
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A comet's ________ is the frozen portion of a comet
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Nucleus
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Particles ejected from a comet can cause a ________ on Earth.
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Meteor Shower
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The ________ extends from about beyond the orbit of Neptune to about twice the distance of Neptune from the Sun
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Kuiper belt
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The Kuiper Belt objects have orbits that
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Lie just beyond Neptune and close to the ecliptic
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Halley's Comet last passed Earth in 1986. It will be due back in
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2061
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What part of a comet has only been seen by a space probe?
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Nucleus
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Most comets are discovered when their coma develops, giving them a fuzzy appearance instead of stellar such as asteroids
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True
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The orbits of most comets
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Lie almost entirely beyond the orbit of Neptune
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What are comets made of?
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All of the above
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The Oort cloud is thought to be
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The spherical cloud of comets and some larger icy bodies surrounding the outer solar system
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Long period comets are thought to reside mainly in the
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Oort Cloud
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Pluto's classification as a planet has been called into question
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True
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Pluto is smaller than many moons in the solar system
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True
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Pluto's orbit takes it closer to the Sun than Neptune for part of its orbit
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True
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Pluto is visible to the naked eye on extremely dark nights
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False
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What is so unusual about Pluto's orbit
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It is more inclined to the ecliptic than any of the eight planets
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The two names most associated with the discovery of Pluto are
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Lowell and Tombaugh
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Charon's orbit
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Is highly inclined to Pluto's orbital plane
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Which of the following gives direct information about the age of the solar system?
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Meteorites from asteroid debirs
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The most famous asteroid impact scar on Earth is located in
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Arizona
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Meteorites are valuable to astronomers because
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They may provide evidence about the process in which the solar system was born
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Large meteroids are thought to collide with Earth
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A few times every million-year period
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Iron meteorites are believed to come from
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The core of a dense M-type asteroid, now broken up
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Carbonaceous Chrondrites are believed to come from
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The crust of a differentiated C-type asteroid, now broken up
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The body which wiped out the dinosaurs was about
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as big as one of Mar's moons
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The Perseid meteor shower gives us about a meteor every minute in mid
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August
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Meteor showers result when asteroids collide and this debris showers the inner solar system
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True
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Some meteorites found on Earth are believed to have originated from the Moon or Venus
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True
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In terms of composition the Jovian planets
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are more like the Sun than are the terrestrials
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In terms of its orbit, which of the terrestrials is oddest?
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Mercury
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Why are the Jovian planets so large?
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They formed the largest protoplanets which swept gas from the solar nebula
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What is a distinguishing characteristic of planetesimals which was critical to planetary formation?
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They were large enough so that their gravity could attract more material and still grow larger
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How did Mercury's location in the solar system affect its composition?
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Mercury is rich in metals because only metallic grains could survive the high temperatures so near the Sun
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How does the melting and vaporization point of materials determine the composition of the planets?
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Durable solids that are very hard to melt and vaporize form close to the Sun, making terrestrial planets.
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The concept that Jupiter and the other Jovians formed farther out than their present orbits is called
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planetary migration
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The perturbations of Mars' gravity prevented large planets from forming in the asteroid belt
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False
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The Oort cloud is believed to be
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A spherical cloud of cometary nuclei far beyond the Kuiper Belt
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The most distant objects in our solar system are
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in the Oort Cloud
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Which of the following is not icy in composition
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Asteroids
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The Kuiper Belt is
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A collection of asteroid-sized icy bodies located outside the orbits of Neptune
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The chief reason the asteroid belt formed is because
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the gravitational perturbation of Jupiter disrupting stable orbits there
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Why did a major planet not form out where the Kuiper Belt now lies?
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Some may have, but they have since migrated to orbits nearer the Sun
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Objects that are in a 3:2 orbital resonance with Neptune are called
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Plutinos
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Which of these is not a consequence of resonance?
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Venus' cloud and surface rotation rates
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A late collision with a large planetismal may have caused what feature on Mars?
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Its curious north-south asymmetry
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"Catasrophes" are NOT needed to explian
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The asteroid belt
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Some type of catastrophe is likely needed to explain the highly tiled rotational axis of Uranus
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True
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Most scientists think catastrophes played little role in the solar system's history
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False
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Most extrasolar planets are hot Jupiters, discovered in the infrared by the Spitzer Space telescope
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False
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We now know of over 100 jovians, but no terrestrial planets around other stars similar to the the Sun.
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True
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Around other suns, we have found Jupiters where Mercury should be.
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True
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None of the other stars yet studied has more than one planet orbiting it
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False
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Which statement about extrasolar planets found to date is true?
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Some are so close to their stars that their periods are just a few days.
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So far, beyond the solar system the extrasolar planets found have been mostly
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Large jovians with terrestrial-type orbits
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Most of the extrasolar planets found have been mostly
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Noting the Doppler shifts of the star as the planet orbits it from side to side
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When we are lucky enough to see an extrasolar planet transit its star
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We can by the drop in light find the planet's size, mass, and density
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As of early 2004, the number of extra solar planets found was
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Over 120, around over 100 typical nearby stars
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Concerning our solar nebula theory, the presence of so many "hot Jupiters" gives us problems with how they can form that close to their star
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True
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According to the Solar Nebula theory, planets
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Should be a common result of star formation
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In comparing our own solar system with others found to date, we find:
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all of the above
