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84 Cards in this Set
- Front
- Back
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The first step of the proton-proton cycle of hydrogen fusion is?
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1h + 1h --> 2H + e + v
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What product of hydrogen fusion immediately escapes into space at high velocity?
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A neutrino
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A star that has a parallax of .1" (.1 seconds of arc or angle) is at a distance from the sun of?
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10 parsecs
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The radius of a typical white dwarf is?
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About the same as the earth
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If we took a proper census of all stars within 62 parsecs of the sun, we would find that the majority of these stars are?
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Main sequence stars
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The contraction of a pre-main-sequence star stops when?
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The central temp rises to about 10^7 degrees Kelvin
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A reflection nebula looks bluer than the star that illuminates it because?
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Dust in the nebula reflects blue light better than red.
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The main-sequence lifetime of a star that has one solar mass is?
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10^12 years
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The processes that make an emission nebula shine are _____, recombination, and cascade.
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ionization
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The core of the sun eventually will consist of carbon and oxygen, produced by?
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Helium fusion
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The person who received a Nobel prize for the discovery that the maximum mass of a white dwarf is 1.4 solar masses was?
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Subrahmanyan Chandrasekhar
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The element from which no nuclear energy can be extracted is?
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Iron
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Where does the escape velocity exceed the speed of light?
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Inside the event horizon of a black hole
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A single (non-binary) star that has 5 solar masses when it arrives on the main sequence will end up as a?
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White dwarf
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If matter flows into a black hole?
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The radius of the black hole's event horizon increases
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A nuclear-powered supernova involves sudden fusion of?
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Carbon and oxygen near the center of a white dwarf
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If we are to measure the mass of a star (other than the sun), the star must?
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Be in a binary system
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Iron nuclei disintegrate into protons and nuetrons when?
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When the core of a massive star undergoes catastrophic collapse
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Suppose you step onto a white dwarf that has the mass of the sun but the radius of the Earth, how much will you weigh?
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300,000 times more than you weigh on Earth
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In the sun, how is energy transported from the center to the surface?
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By radiation in the core and by convection in the envelope
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A star that has the same radius as the sun, but whose photosphere has a temperature of 50,000 degrees Kelvin?
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Looks bluer than the sun and has a higher luminosity.
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A nucleus that contains two protons and one neutron is?
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3He (a stable but rare form of Helium)
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Can an atom with its electron in an excited state spontaneously emit a photon as its electron makes a transition to a less excited state?
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Yes
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A star of spectral type O has weaker absorption lines of neutral hydrogen than a star of spectral type A because?
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Hydrogen is practically all ionized in the O-type star
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The sun's chromospher is?
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Hotter than the photospher
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If you know the value of the Hubble constant you can?
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Make a rough estimate of how long the universe has been expanding.
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The hubble law tells us that?
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The universe is undergoing a uniform expansion.
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The main argument for building the Hubble Space Telescope was to use it to?
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Measure distances to galaxies and determine the value of the hubble constant
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We observe quasars only at large distances from us. This tells us that?
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Quasars are things of the past
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It may be that someone, somewhere, is observing our galaxy and seeing?
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an AGN
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Synchrotron radiation can be emitted by?
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Electrons moving near the speed of light
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What did Einstein believe about rest?
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There is no absolute standard of rest.
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Can we see into the past?
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Yes
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The cosmic microwave background was emitted?
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When the temperature of the universe was about 3000 K
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What is the cosmological principle?
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The assumption that the universe beyond our horizon is much like the universe within our horizon.
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If the volume of the universe is finite, rather than infinite, then?
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Space must be curved
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The best way to think about the cosmic expansion is?
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Space is expanding and carrying galaxies with it.
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When did Big-bang nucleosynthesis take place?
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A few minutes after the big bang.
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At a redshift of one (z=1) the universe?
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Was half its present size
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What is the horizon problem?
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The cosmic microwave background is so smooth
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If inflation occurred, then?
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We should find on the large scale, space is indistinguishable from flat
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Tiny fluctuations in the brightness of the Cosmic Microwave Background from place to place on the sky tell us that?
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Space is indistinguishable from flat
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Observations of very remote thermonuclear supernovae indicate that?
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The expansion of the universe is accelerating.
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Einstein introduced the cosmological constant into general relativity because he thought that the universe was?
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Static
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The age of the globular clusters in our galaxy is?
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About 13 billion years
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The total mass of the matter that is nearer to the center of our galaxy than we are is about?
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100 billion solar masses
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The time required for the sun to complete one orbit around the center of our Galaxy is about?
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.24 Gyr
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The existence of the disk of our galaxy is a consequence of?
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the rotation of the gas cloud that contracted to form our Galaxy
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Our Galaxy is what type of galaxy?
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A spiral galaxy
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An E0 galaxy looks circular rather than elliptical. What is its true shape?
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Spherical
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Is the distance to the nearest star longer than a light year?
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Yes
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Can Pavo be seen from Norman?
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No
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Which looks brighter, Sirius -1.5, or Rigel .1?
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Sirius
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Sirius Procyon and Betelgeuse form what constellation?
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The winter triangle
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What is the vernal equinox?
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Sun is up for 12 hours, spring, sun will be on the ecliptic, sun will be on celestial equator
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From here polaris can be seen?
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35 degrees above the north horizon
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The third quarter moon sets at?
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noon
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The moon, as viewed from Earth, drifts through the constellations at the rate of?
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About 13 degrees per day
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What will earth be like a billion years from now?
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Rotation period will be longer, moon's orbit will be longer, tides will be weaker
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The maximum length of a total solar eclipse is?
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7.5 minutes
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The heliocentric model of Copernicus didn't work better than Ptolemy's model because?
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Copernicus stayed with circular orbits
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One implication of Kepler's second law (equal areas in equal times) is that?
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A planet moves faster when its closer to the sun, slower when its further.
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The first person on Earth to view the phases of Venus was?
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Galileo
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Newton's first law of motion, about inertia, says that?
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It takes a force to change a motion.
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A satellite that moves in a circular orbit about Earth?
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Constantly accelerates, in the direction toward Earth
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What is the order of wavelength, from longest to shortest?
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radio, infrared, optical, ultraviolet, x-ray, gamma-ray
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A radio photon might have a wavelength of?
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A meter
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True or false, Earth's atmosphere transmits only the visual part of the electromagnetic spectrum?
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False
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Is magnifying power a concern to a ground based telescope?
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Yes, but its the least
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The focal arrangement that was used for the first reflecting telescope is called?
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Newtonian
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As a consequence of the tidal interaction between Earth and the moon?
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The moon rotates on its axis in the same amount of time as it orbits Earth
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The resolving power of a two-dish radio interferometer depends on the?
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Distance between the two dishes
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"De Revolutionibus..." was written by?
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Copernicus
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The escape velocity from near the surface of the moon is?
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2.4 km/sec
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What are the four stages of planetary evolution?
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Differentiation, Cratering, Flooding, and Slow Surface Evolution
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What is differentiation?
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The separation of material according to density.
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What is Cratering?
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Heavy bombardment of the early solar system by interstellar matter.
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What is flooding?
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First, molten material floods basins, later as the surface cools water fell as rain and formed the oceans
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What is slow surface evolution?
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The constant change of earth's surface from plate movement, and erosion.
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What is the rough temperature of Earth's core?
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6000K.
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What are the P waves?
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Waves that can penetrate liquid and travel like sound waves.
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What are S waves?
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Travel as side to side vibration can pass through liquid.
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What did the primary atmosphere consist of?
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Carbon dioxide, nitrogen, water vapor.
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What does the secondary atmosphere consist of primarily?
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Oxygen and nitrogen.
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