Astronomy Notecards 2

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  1. If the Moon is setting at 6 A.M., the phase of the Moon must be
  2. Why do we see essentially the same face of the Moon at all times?
    because the Moon's rotational and orbital periods are equal
  3. What conditions are required for a solar eclipse?
    The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun.
  4. In addition to the conditions required for any solar eclipse, what must also be true in order for you to observe a total solar eclipse?
    The Moon's umbra must touch the area where you are located.
  5. What causes the apparent retrograde motion of the planets?
    As Earth passes another planet, the other planet appears to move backward with respect to the background stars, but the planet's motion does not really change.
  6. What do the structures of Stonehenge, the Templo Mayor, the Sun Dagger, and "Woodhenge" all have in common?
    They were all used by ancient peoples for astronomical observations.
  7. How did Eratosthenes estimate the size of Earth in 240 B.C.?
    by comparing the maximum altitude of the Sun in two cities at different latitudes
  8. How did the Ptolemaic model explain the apparent retrograde motion of the planets?
    It held that the planets moved along small circles that moved on larger circles around Earth.
  9. When Copernicus first created his Sun-centered model of the universe, it did not lead to substantially better predictions of planetary positions than the Ptolemaic model. Why not?
    Copernicus used perfect circles for the orbits of the planets.
  10. Kepler's third law, p2 = a3, means that
    all orbits with the same semimajor axis have the same period.a planet's period does not depend on the eccentricity of its orbit.the period of a planet does not depend on its mass.planets that are farther from the Sun move at slower average speeds than nearer planets.
  11. Kepler's second law, which states that as a planet moves around its orbit it sweeps out equal areas in equal times, means that
    a planet travels faster when it is nearer to the Sun and slower when it is farther from the Sun.
  12. Galileo observed all of the following. Which observation offered direct proof of a planet orbiting the Sun?
    phases of Venus
  13. What do scientists mean by verifiable observations?
    statements that a person can, in principle, verify for himself or herself
  14. What is meant by Occam's Razor?
    the idea that scientists should prefer the simpler of two models that agree equally well with observations
  15. Which of the following statements about scientific theories is true?
    A theory must make predictions that can be checked by observation or experiment.If even a single new fact is discovered that contradicts what we expect according to a particular theory, then the theory must be revised or discarded.A theory is a model designed to explain a number of observed facts.A theory can never be proved beyond all doubt; we can only hope to collect more and more evidence that might support it.
  16. Which of the following best describes why the smaller terrestrial worlds have cooler interiors than the larger ones?
    They have relatively more surface area compared to their volumes.
  17. Why does Earth have the strongest magnetic field among the terrestrial worlds?
    It is the only one that has both a partially molten metallic core and reasonably rapid rotation.
  18. What type of stresses broke Earth's lithosphere into plates?
    the circulation of convection cells in the mantle, which dragged against the lithosphere
  19. Which of the following describes tectonics?
    the disruption of a planet's surface by internal stresses
  20. Which of the following describes erosion?
    the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather
  21. Which of the following describes volcanism?
    the eruption of molten rock from a planet's interior to its surface
  22. Which of the following describes impact cratering?
    the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface
  23. Which two geological processes appear to have been most important in shaping the present surface of Venus?
    volcanoes and tectonics
  24. What provide evidence that Mars once had abundant liquid water on its surface?
    the presence of very old craters that appear to have been eroded by rainthe presence of features that look like dried up river bedsthe presence of "blueberries" made of the mineral hematite
  25. Rank the five terrestrial worlds in order of size from smallest to largest:
    Moon, Mercury, Mars, Venus, Earth.
  26. Which internal energy source is the most important in continuing to heat the terrestrial planets today?
  27. Which of the following worlds have the thinnest lithospheres?
    Earth and Venus
  28. What is differentiation in planetary geology?
    the process by which gravity separates materials according to density
  29. When we see a region of a planet that is not as heavily cratered as other regions, we conclude that
    the surface in the region is younger than the surface in more heavily cratered regions.
  30. Volcanism is more likely on a planet that
    has high internal temperatures.
  31. How did the lunar maria form?
    Large impacts fractured the Moon's lithosphere, allowing lava to fill the impact basins.
  32. Why do we think Mercury has so many tremendous cliffs?
    They were probably formed by tectonic stresses when the entire planet shrank as its core cooled.
  33. In the context of planetary geology, what do we mean by outgassing?
    the release by volcanism of gases that had been trapped in a planetary interior
  34. Based on its surface features, the most important event on Venus in the past billion years or so was ________.
    a global "repaving" that erased essentially all the surface features that had existed earlier
  35. The major processes that heat the interiors of the terrestrial worlds are:
    (1) Heat deposited as the planets were built from planetesimals; (2) heat deposited as the planets underwent differentiation; (3) heat released by radioactive decay.
  36. Which of the following is not a characteristic of the inner planets?
    They all have substantial atmospheres.
  37. Which of the following is not a characteristic of the outer planets?
    They have very few, if any, satellites.
  38. How do asteroids differ from comets?
    Asteroids are rocky bodies and are denser than the comets, which are made of icy material.
  39. Why are the inner planets made of denser materials than the outer planets?
    In the inner part of the nebula only metals and rocks were able to condense because of the high temperatures, whereas hydrogen compounds, although more abundant, were only able to condense in the cooler outer regions.
  40. According to the nebular theory, what are asteroids and comets?
    They are leftover planetesimals that never accreted into planets.
  41. According to our theory of solar system formation, why do we find some exceptions to the general rules and patterns of the planets?
    Most of the exceptions are the result of giant impacts.
  42. What do meteorites reveal about the solar system?
    They reveal that the age of the solar system is approximately 4.6 billion years.
  43. According to our theory of solar system formation, why do all the planets orbit the Sun in the same direction and in nearly the same plane?
    The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk.
  44. What do we mean by the period of heavy bombardment in the context of the history of our solar system?
    the first few hundred million years after the planets formed, which is when most impact craters were formed
  45. According to our present theory of solar system formation, which of the following statements about the growth of terrestrial and jovian planets is true?
    Both types of planet begun with planetesimals growing through the process of accretion, but only the jovian planets were able to capture hydrogen and helium gas from the solar nebula.The terrestrial planets formed inside the frost line of the solar nebula and the jovian planets formed beyond it.Swirling disks of gas, like the solar nebula in miniature, formed around the growing jovian planets but not around the growing terrestrial planets
  46. Why isn't there a planet where the asteroid belt is located?
    Gravitational tugs from Jupiter prevented material from collecting together to form a planet.
  47. Processed meteorites with high metal content probably are
    chunks of a larger asteroid that was shattered by a collision.
  48. Why does the plasma tail of a comet always point away from the Sun?
    The solar wind electromagnetically "blows" the ions directly away from the Sun.
  49. Which is closest to the average distance between asteroids in the asteroid belt?
    1 million km
  50. If the hypothesis tracing the extinction of the dinosaurs to an impact is correct, the dinosaurs died off largely because ________.
    of global climate effects initiated by dust and smoke that entered the atmosphere after the impact
  51. What about asteroids is true?
    If we could put all the asteroids together, they would not make an object about the size of Earth.Some are more like loosely bound piles of rubble than solid chunks of rock.Many but not all orbit the Sun in the asteroid belt.Most asteroids are not spherical in shape
  52. Which of the following is not a piece of evidence supporting the idea that Pluto is a large comet of the Kuiper belt?
    Pluto grows a coma and a long tail when it is at the point in its orbit closest to the Sun.
  53. What is evidence supporting the idea that an impact caused the mass extinction that occurred 65 million years ago?
    Unusually large abundances of iridium and other rare metals are found in a layer of clay that dates to 65 million years ago.Grains of quartz formed under high pressure are found in a layer of clay that dates to 65 million years ago.A large impact crater along the coast of Mexico dates to 65 million years ago.
  54. When you see the bright flash of a meteor, what are you actually seeing?
    the glow from a pea-size particle and the surrounding air as the particle burns up in our atmosphere
  55. Which of the following objects are probably not located in the same region of the solar system in which they originally formed?
    asteroids of the asteroid belt
    Oort cloud comets
    Kuiper belt comets
    Oort cloud comets
Card Set:
Astronomy Notecards 2
2013-11-30 21:28:16
Astronomy based quizzes notecards
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