Term
| Approximately how many degrees does your fist take up when held at arms length? |
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Definition
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Term
| What is the cause of the Moon's phases? |
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Definition
| Sun's illumination relative to our viewing location. |
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Term
| If we move two massive objects (like planets) farther apart, what happens to the gravitational force each one feels? |
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Definition
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Term
| When is the Moon largest in the sky? (has the largest angular size) |
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Definition
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Term
| What causes the raised central peaks found in many craters on the Moon? |
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Definition
| Material rebounding from a downward impact. |
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Term
| Why doesn't the Moon have plate tectonics like the Earth? |
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Definition
| The Moon doesn't have enough internal heat left. |
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Term
| What is one reason for the success of the "giant impact" Moon formation theory? |
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Definition
| It explains the lack/deficit of iron in the Moon. |
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Term
| Which piece of evidence for the Cretaceous extinction event being caused by an asteroid impact was discovered by Louis and Walter Alvarez? (which occurred 65 Million years ago - MYA) |
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Definition
| Iridium in the 65MYA sediment layer. |
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Term
| Why don't we see eclipses every month when the Moon is between the Earth and the Sun? |
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Definition
| The Moon's orbit is tilted with respect to the Earth's orbit around the Sun. |
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Term
| When an object moves farther away from you... |
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Definition
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Term
| How long does it take the Moon to spin once on it's axis? |
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Definition
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Term
| What is one way you could estimate the physical size of the Moon if you know the physical size of the Earth? |
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Definition
| Comparing to the size of the Earth's shadow during a lunar eclipse. |
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Term
| Which of the following is NOT a constellation? |
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Definition
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Term
| Which of the following contribute to the temperature change during the seasons? |
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Definition
-The days are longer in summer.
-In winter, the Sun's path is lower in the sky so less heat is received. |
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Term
| On which day(s) is the Sun's path directly over the equator? |
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Definition
-The autumnal equinox (September 22nd)
-The vernal equinox (March 20th) |
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Term
| Dionysius Exiguus decreed that 1 A.D. is (arguably)... |
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Definition
| the first year after Jesus was born. |
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Term
| Between which two planets is the asteroid belt located? |
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Definition
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Term
| Which planet's spin axis is pointed nearest to the ecliptic plane? |
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Definition
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Term
| If you increase the volume a planet takes up without changing the mass what happens to the density of that planet? |
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Definition
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Term
| Why are the outer giant planets so large compared to the inner terrestrial planets? |
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Definition
| They formed farther from the Sun where there was more material. |
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Term
| What plane are the orbits of the planets most closely aligned with? |
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Definition
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Term
| Which of the following is the best analogy for what an epicycle is? |
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Definition
| The path of a point on a spinning frisbee attached to a spinning bicycle wheel on its side. |
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Term
| Which planet(s) can reach an "inferior conjunction" with the Sun (viewed from Earth)? |
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Definition
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Term
| What led Kepler to search for and discover his third law? |
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Definition
| A search for a link between planetary motion and the "music of the spheres". |
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Term
| What two forces caused the solar nebula to flatten into a disk? |
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Definition
-Centrifugal (rotational) force.
-Gravitational force. |
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Term
| Which statement best describes the formation of typical moons and satellites? |
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Definition
| -Formed in a scaled down version of the solar nebula around a planet. |
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Term
| In what order did the growth phases occur in the solar nebula? 1. Gravitational force dominated growth 2. Random collision dominated growth 3. Electro-static dominated growth 4. Gas/atmosphere accretion |
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Definition
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Term
| Differentiation led to which of the following? |
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Definition
| Redistributing material within a planet according to its density. |
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Term
| Which method of planet detection has discovered the most planets to date? |
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Definition
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Term
| Which of the following is a limitation of the radial velocity method? |
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Definition
-It has difficulty detecting planets on orbits perpendicular to the line of sight.
-It can only give a lower limit on the planet's mass.
-It can only be used effectively on relatively bright/close stars. |
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Term
| Which method of planet detection tells us the most about the planets discovered? |
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Definition
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Term
| Which of the following accurately describe the majority of the detected extrasolar planets/orbits? |
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Definition
-Short, rapid orbits
-Large, high mass planets |
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Term
| Which of the Galilean satellites is believed to have a liquid water layer below its icy crust? |
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Definition
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Term
| Saturn's moon Titan was seen to have rivers cutting through the landscape. What are these carved by? |
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Definition
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Term
| When was Pluto's mass able to be calculated? |
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Definition
| When its moon was discovered. |
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Term
| Which trans-Neptunian object's discovery prompted Pluto's demotion from a "planet" to a "dwarf planet"? |
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Definition
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Term
| Which one of the following uses the method of triangulation? |
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Definition
| Looking at a building from two locations and using the distance between the two locations and the angles to the building to determine how far away it is. |
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Term
| Why was stellar parallax not observed until 1830? |
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Definition
| The parallax angle for most stars is so small. |
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Term
| If you double the distance to a star, what happens to its parallax angle? |
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Definition
| The parallax angle becomes 2x smaller. |
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Term
| Which star appears the brightest? |
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Definition
| 1st magnitude star (m=1.0) |
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Term
| What allows sunspots to occur on the Sun? |
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Definition
| Feedback between the magnetic fields and inflowing charged gas particles. |
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Term
| Which of the following solar activities is the most powerful? |
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Definition
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Term
| What is the underlying cause of the solar cycle? |
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Definition
| The Sun rotates faster around its equator than at its poles. |
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Term
| What information can you determine from looking at the spectrum of light coming from an astronomical object? |
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Definition
| The object's chemical/atomic composition. |
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Term
| The photosphere of the Sun is which of the following? |
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Definition
| The region of the Sun where the gas goes from opaque to transparent. |
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Term
| Why do astronomers believe that the central temperature of the Sun is 15 million degrees Kelvin (K)? |
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Definition
| Because a lower or higher central temperature would lead to a surface energy output that is either lower or higher than observed. |
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Term
| Which motions does solar- (Helio-) seismology study? |
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Definition
| The large scale convecting motions of the Sun's outer layers. |
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Term
| Which of the following is the source of the Sun's energy? |
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Definition
| Nuclear energy - from the fusion of Hydrogen into Helium. |
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Term
| Which of the following statements is true about the main sequence lifetimes of stars? |
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Definition
| Smaller stars live longer because they burn their mass/fuel more slowly. |
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Term
| Why do stars become *RED* giants after they finish their lives on the main-sequence? |
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Definition
| Because they expand and their surfaces cool - making the surface redder. |
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Term
| What is the cause of the runaway compression and burning that leads to the helium flash in smaller stars? |
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Definition
| Electron degeneracy pressure. |
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Term
| What determines whether a star will cool or ignite Helium fusion after it runs out of Hydrogen? |
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Definition
| If it has enough mass/gravity to compress and heat the core up to high enough temperatures. |
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Term
| Which statement is true about star's temperatures and colors? |
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Definition
| The hottest stars appear blue. |
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Term
| Which type of star is NOT represented/present in the HR diagram? |
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Definition
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Term
| What would happen if molecular gas clouds couldn't radiate away their heat/energy? |
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Definition
| They wouldn't be able to collapse enough to form stars. |
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Term
| Which of the following statements is true about how stars form? |
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Definition
| Stars typically form in groups from fragments inside a molecular cloud. |
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Term
Approximately what Hubble type is the following galaxy?
[image]
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Definition
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Term
| In terms of the ages of their stars, which order puts the types of galaxies from youngest to oldest? |
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Definition
| Irregulars, Spirals, Ellipticals |
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Term
| Which fact allows us to see galaxies as they were in the early Universe? |
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Definition
| The speed of light is finite. |
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Term
| Why do we see more large elliptical galaxies in regions with many galaxies close to each other? |
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Definition
| Because when galaxies are close to each other they merge and form large ellipticals. |
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Term
| If our galaxy was spherical (shaped like a sphere) how would the stars be distributed on the sky from our point of view? |
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Definition
| Uniformly spread across the sky. |
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Term
| How was Herschel able to estimate the size and shape of the galaxy? |
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Definition
| Counting stars in different regions of the sky. |
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Term
| Which two are advantages of studying globular clusters of stars to determine the size of the galaxy? |
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Definition
-They are very luminous.
-They are often above or below the galactic plane. |
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Term
| Which of the following is NOT a main component of the Milky Way galaxy? |
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Definition
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Term
| The majority of galaxies in our local cluster/group (and by extension in many other groups of galaxies) are of what type? |
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Definition
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Term
| The "Great Attractor" is which of the following? |
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Definition
| A cluster of superclusters. |
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Term
| Which of the following is NOT a term used to describe large scale structure? |
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Definition
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Term
| Which of the following is physically the smallest? |
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Definition
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Term
| Where does the energy that an active galaxy emits come from? |
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Definition
| From the accretion disk around the super-massive black hole at the center. |
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Term
| If there was no intergalactic gas around radio galaxies, the radio lobes/jets would be… |
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Definition
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Term
| How do we know that AGN are physically small compared to the spacing between stars? |
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Definition
| Because light from both the near and far side reach us only hours apart. |
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Term
| How does gas fall into the super-massive black holes at the centers of active galaxies? |
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Definition
| It collides with other gas and so loses its energy, spiraling inwards. |
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Term
| In a spiral galaxy, as you look at stars that are further and further out of the center of the galaxy, what happens to the rotational speed of the stars? |
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Definition
| They orbit at the same speed. |
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Term
| Why is it difficult to observe light in visible wavelengths from the center of the Milky Way? |
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Definition
| Because interstellar dust blocks out the light. |
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Term
| What does the winding dilemma claim? |
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Definition
| That spiral arms could NOT retain their shape as their stars orbit, given the differential rotation. |
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Term
| Olbers' paradox states that... |
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Definition
| The night sky should be completely covered with stars and galaxies, so it should be bright. |
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Term
| The Cosmic Microwave Background (CMB) radiation is a surface we cannot see past, analogous to which of the following "surfaces": |
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Definition
| The photosphere of a star. |
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Term
| Which of the following is closest to the temperature of the Cosmic Microwave Background (CMB) radiation today? |
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Definition
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Term
| In a Universe with positive curvature (a "closed" Universe), distant galaxies should appear... |
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Definition
| Larger than they really are. |
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Term
| Which of the following statements is true because space is expanding (and would not be true if space were fixed and galaxies were simply flying away from each other)? |
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Definition
| Light takes longer to reach us because more space is created for it to travel across. |
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Term
| What of the following is closest to the current best estimate of the age of the Universe? |
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Definition
| 14 billion years old (1.4x10^10) |
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Term
| What does the cosmological principle claim? |
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Definition
| That there is no preferred location in the Universe. |
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Term
| A galaxy whose spectral lines are more red-shifted is doing which of the following? |
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Definition
| Moving away from us very quickly. |
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Term
| What would happen to our estimates of the distances to distant galaxies if we realized that the Hubble constant should be twice as big as it is now? |
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Definition
| The galaxies would be 1/2 as far away as previously thought. |
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Term
| What equation allows us to measure the distances to galaxies in which we see Type Ia supernovae? (think about what the book says we know about these types of supernovae) |
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Definition
| Inverse-Square Law: relates brightness of something (B) to its luminosity (L) and its distance from us (d) |
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Term
| What is happening to the expansion of the galaxies/Universe? |
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Definition
| It is speeding up (accelerating) because of the repulsive (anti-gravity) effect of dark matter. |
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Term
| What is the reason that we are made of matter and not antimatter? |
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Definition
| Antiquarks are able to decay while quarks are not, so there were more quarks than antiquarks in the early Universe. |
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Term
| The epoch of inflation is which of the following? |
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Definition
| A brief burst of intense expansion in the early history of the Universe. |
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Term
| What is the Horizon problem? |
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Definition
| The CMB temperature is the same from regions that are so far apart that they had no way to coordinate. |
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Term
| How long will it take for gravity to pull the Milky Way into the Virgo Cluster? |
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Definition
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