Rotating Question Curious About Astronomy? Ask an Astronomer

Previously answered questions by Dave Rothstein

(in order of times viewed)

  1. What is the universe expanding into?
  2. Is the universe expanding faster than the speed of light?
  3. How can we see the Milky Way if we are inside it?
  4. Can we feel the Earth spin?
  5. Does your weight change between the poles and the equator?
  6. Why hasn't NASA gone back to the moon?
  7. How long does a solar eclipse last?
  8. How do you calculate the lifetime of the Sun?
  9. What is the observational difference between a star and a planet?
  10. What is the physical difference between a star and a planet?
  11. Does evolution contradict the second law of thermodynamics?
  12. What is apparent magnitude?
  13. Does gravity vary across the surface of the Earth?
  14. How do astronomers use math in their jobs?
  15. What would happen if the gravity on Earth was suddenly turned off?
  16. Why isn't the sky bright at night if the universe has so many stars?
  17. What is the density of a black hole?
  18. Do most astronomers believe in God based on the available scientific evidence?
  19. What happens to a substance if its speed is more than the speed of light?
  20. Why is the moon in a different place every night?
  21. When the Sun converts mass to energy, do the orbits of the planets change?
  22. Why doesn't the length of each day change much around the solstices?
  23. How long would it take the Earth to fall into the Sun?
  24. Could there be life in the galaxies nearest to the Milky Way?
  25. How does astronomy benefit humankind?
  26. What is a star's "spectrum"?
  27. How do astronauts use math in their jobs?
  28. What can we learn from the color of a star?
  29. If gravity is a "curvature of space" rather than a force, why do a ball and bullet follow different paths?
  30. What is the difference between the "Doppler" redshift and the "gravitational" or "cosmological" redshift?
  31. What are "blue stragglers" in globular clusters?
  32. How do we know that nuclear fusion is still going on in the Sun?
  33. Can you see the future as you fall into a black hole?
  34. What companies or businesses can astronomers work for?
  35. Why do clocks turn in the opposite direction from the Earth and Moon?
  36. How do we define distance in an expanding universe?
  37. When we look back to the Big Bang, why don't we see the universe as a tiny speck of matter?
  38. How does the brightness of a star depend on its distance from us?
  39. How do astronauts communicate with their families from space?
  40. Will the Moon be invisible in 500 million years?
  41. Will we ever stop having solar eclipses because of the moon's motion away from the Earth?
  42. Why do astronauts in space need to exercise?
  43. How can we distinguish a star's "real" color from the change in color that we observe due to the star's motion?
  44. Is the universe really like an expanding balloon?
  45. What is the farthest in space that we have gone?
  46. What does the term "visible universe" mean?
  47. How can we see galaxies if their stars are so faint?
  48. Do we see the same stars from above and below the equator?
  49. How close does a supernova need to be to damage the Earth's environment?
  50. What process would bring about a quark star?
  51. What happened to all the black holes that were around in the early universe?
  52. How can we compare dark matter and dark energy?
  53. How long do supernova remnants last?
  54. Would extraterrestrial civilizations know that there is life on Earth?
  55. Could there have been multiple Big Bangs at different places in the universe?
  56. Could dark energy come from matter anti-matter pairs forming spontaneously and then annihilating?
  57. Why are accretion disks flat?
  58. Can gravitational lensing from intervening galaxies cause the observed ripples in the Cosmic Microwave Background?
  59. Have astronomers observed any phenomena that could be produced by extraterrestrial civilizations?
  60. Why do spacecraft need heat shields coming back to Earth but not leaving?
  61. Why do some eclipses take longer than others?
  62. How can we understand the meaning of large numbers like "a million million?"
  63. Is light of different colors affected differently by gravity?
  64. Why aren't accretion disks around giant stars as hot as accretion disks around black holes?
  65. When measuring the expansion of the universe, do astronomers consider that they're seeing how galaxies moved long ago, not today?
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URL: http://curious.astro.cornell.edu/authorlist.php?number=4
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Last modified: November 19, 2007 11:28:35 AM

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