Rotating Question Curious About Astronomy? Ask an Astronomer

All previously answered questions (in order of times viewed)

  1. What's going to happen on December 21st 2012? (viewed 2124201 times)
  2. What color is each planet? (viewed 896353 times)
  3. At what speed does the earth move around the sun? (viewed 570910 times)
  4. Is the Moon moving away from the Earth? When was this discovered? (viewed 550581 times)
  5. How far is each planet from Earth? (viewed 463038 times)
  6. When will Halley's Comet return? (viewed 417463 times)
  7. How many stars are there in our Galaxy (Milky Way)? (viewed 385596 times)
  8. How long does it take for the Sun's light to reach us? (viewed 384975 times)
  9. Why do the planets orbit the sun? (viewed 371688 times)
  10. What is the universe expanding into? (viewed 366782 times)
  11. How do you measure the distance between Earth and the Sun? (viewed 334764 times)
  12. Which planets have rings? (viewed 320856 times)
  13. Why do stars twinkle? (viewed 315565 times)
  14. Does the Moon rotate? Are there other moons that always keep one face toward their planet? (viewed 298348 times)
  15. How do I build a model rocket? (viewed 287816 times)
  16. What color is Venus? (viewed 271489 times)
  17. What is a white hole? (viewed 265285 times)
  18. Can you hear sounds in space? (viewed 251886 times)
  19. What is the life cycle of a star? (viewed 244776 times)
  20. What are the names of the earth, moon, sun, and solar system? (viewed 236272 times)
  21. What makes the Earth rotate? (viewed 228475 times)
  22. What is that ring (or rainbow) around the moon? (viewed 227508 times)
  23. What are shooting stars? (viewed 226565 times)
  24. What is the largest star? (viewed 221358 times)
  25. What do astronauts eat in space? Can they grow food? (viewed 207467 times)
  26. How do we know the age of the Universe and the Earth? (viewed 203400 times)
  27. Why do planets rotate? (viewed 202892 times)
  28. Can artificial gravity be created in space? (viewed 202202 times)
  29. Is the universe expanding faster than the speed of light? (viewed 198379 times)
  30. What are the different kinds of astronomers? (viewed 193035 times)
  31. How does the location of sunrise and sunset change throughout the year? (viewed 188751 times)
  32. Where did the name 'Earth' come from? (viewed 178840 times)
  33. How can we see the Milky Way if we are inside it? (viewed 178037 times)
  34. What would happen if we did not have a Moon? (viewed 174125 times)
  35. Why isn't the sky bright at night if the universe has so many stars? (viewed 173303 times)
  36. How many Earths fit into the Sun? (viewed 171985 times)
  37. Why is a day divided into 24 hours? (viewed 167339 times)
  38. How does the position of Moonrise and Moonset change? (viewed 162732 times)
  39. Who named the planets and who decides what to name them? (viewed 156499 times)
  40. Why are the Moon and Sun sometimes orange or red? (viewed 154433 times)
  41. When was the last time all 9 planets were aligned? (viewed 152931 times)
  42. Why do airplanes take longer to fly West than East? (viewed 150502 times)
  43. Is Pluto a planet? (viewed 149749 times)
  44. Is the distance from the Earth to the Sun changing? (viewed 148920 times)
  45. What is at the end of the Universe? (viewed 145219 times)
  46. How can I find the star I have "bought"? (viewed 141550 times)
  47. How much money is spent on space exploration? (viewed 140664 times)
  48. Why are there both high and low tides? (viewed 130321 times)
  49. How do astronauts take baths and use restrooms in space? (viewed 129371 times)
  50. What direction do planets rotate? (viewed 128425 times)
  51. Can we feel the Earth spin? (viewed 128078 times)
  52. Is the Sun expanding? Will it ever explode? (viewed 126986 times)
  53. What is the largest galaxy? (viewed 126933 times)
  54. What is a nova? (viewed 126622 times)
  55. How many known galaxies are there? (viewed 125718 times)
  56. Does your weight change between the poles and the equator? (viewed 123594 times)
  57. Do stars move in the sky? (viewed 121669 times)
  58. Can I buy a star? (viewed 116646 times)
  59. What are the advantages and disadvantages of using a telescope in space? (viewed 116295 times)
  60. Why do all the planets orbit in the same plane? (viewed 114005 times)
  61. Will the sun go supernova in six years and destroy Earth (as seen on Yahoo)? (viewed 113999 times)
  62. How are light and heavy elements formed? (viewed 111953 times)
  63. Are there telescopes that can see the flag and lunar rover on the Moon? (viewed 111622 times)
  64. What is the hottest time of day? (viewed 111074 times)
  65. Does the Sun have a scientific name? (viewed 110275 times)
  66. Why hasn't NASA gone back to the moon? (viewed 110138 times)
  67. How do stars move in the Galaxy? (viewed 109936 times)
  68. What happens when galaxies collide? (viewed 109672 times)
  69. Who first measured the speed of light? (viewed 108743 times)
  70. Why do planets have elliptical orbits? (viewed 108291 times)
  71. How do rockets work? (viewed 108033 times)
  72. What is the size of the Solar System? (viewed 107295 times)
  73. Will the magnetic field of the Earth reverse its direction in the future? Will this cause problems? (viewed 106681 times)
  74. What was there before the Big Bang and what is there outside of our universe? (viewed 106243 times)
  75. What would happen if an impact caused Earth to stop rotating? (viewed 106148 times)
  76. What is the physical difference between a star and a planet? (viewed 105982 times)
  77. When is the next comet due to arrive? (viewed 105961 times)
  78. How much money do astronomers make? (viewed 105928 times)
  79. How long does a solar eclipse last? (viewed 104133 times)
  80. What will happen to life on Earth when the Sun becomes a red giant? (viewed 103890 times)
  81. Do black holes die? If so how? (viewed 103700 times)
  82. Does evolution contradict the second law of thermodynamics? (viewed 103409 times)
  83. How do you calculate the lifetime of the Sun? (viewed 102854 times)
  84. How many constellations are there? (viewed 102633 times)
  85. What elements make up the Sun? (viewed 102364 times)
  86. What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (viewed 101881 times)
  87. What is the observational difference between a star and a planet? (viewed 100495 times)
  88. Does the Sun rotate? (viewed 100070 times)
  89. What's the difference between astronomy and astrology? (viewed 99423 times)
  90. Does the Sun move around the Milky Way? (viewed 99030 times)
  91. What do astronauts do all day in the International Space Station? (viewed 98482 times)
  92. What is apparent magnitude? (viewed 95191 times)
  93. Does gravity vary across the surface of the Earth? (viewed 94210 times)
  94. Which planet is most similar to Earth? (viewed 93909 times)
  95. What would happen if the gravity on Earth was suddenly turned off? (viewed 93602 times)
  96. How many meteorites hit Earth each year? (viewed 93579 times)
  97. What are constellations used for? (viewed 91312 times)
  98. If Mars is only about 35-60 million miles away at close approach, why does it take 6-8 months to get there? (viewed 90998 times)
  99. How do astronomers use math in their jobs? (viewed 90071 times)
  100. How critical is the Earth-Sun distance in maintaining our average temperatures on Earth? (viewed 90059 times)
  101. Why do different stars appear with seasons? (viewed 89767 times)
  102. Why are stars and planets round? (viewed 88796 times)
  103. Where did the Universe come from? (viewed 88599 times)
  104. What kind of schooling is necessary to become an astronomer? (viewed 88557 times)
  105. Is there a proof that Earth moves? (viewed 88469 times)
  106. Does the Sun orbit the Earth as well as the Earth orbiting the Sun? (viewed 87836 times)
  107. Why is the Universe flat and not spherical? (viewed 87763 times)
  108. Why is the Moon so bright? (viewed 87705 times)
  109. Have astronomers discovered Earth's second moon? (viewed 87368 times)
  110. What makes the wind? (viewed 87147 times)
  111. What would happen if an asteroid 10 kilometers across hit the Earth? (viewed 86512 times)
  112. What is a singularity? (viewed 85978 times)
  113. How can a star burn with no oxygen? (viewed 84922 times)
  114. What is the difference between a "star" and a "sun"? (viewed 82852 times)
  115. Where does the name "Milky Way" come from? (viewed 82165 times)
  116. Why does the Earth tilt back and forward once a year? (viewed 82010 times)
  117. What are RA and DEC? (viewed 81743 times)
  118. What would happen if Earth had more than one moon? (viewed 80716 times)
  119. Considering the motion of the Earth, the solar system, and the galaxy, how fast am I moving while lying in bed asleep? (viewed 80224 times)
  120. Since Earth is spinning, why do we land in the same place when we jump or fall? (viewed 78681 times)
  121. What are the requirements for being a planet? (viewed 78232 times)
  122. What kind of rock is the moon made of? (viewed 77823 times)
  123. How many stars are born and die each day? (viewed 77512 times)
  124. Why aren't there any green stars? (viewed 77182 times)
  125. Did astronauts really go to the Moon, or is it a hoax? (viewed 76936 times)
  126. How are galaxies formed? (viewed 76571 times)
  127. Will the Sun become a black hole one day? (viewed 74506 times)
  128. How are black holes made? Could one be made close to us? (viewed 74391 times)
  129. What is the density of a black hole? (viewed 73808 times)
  130. What would happen if a supermassive black hole came close to the Earth? (viewed 73807 times)
  131. Who has landed on the moon? (viewed 73261 times)
  132. Why is the moon in a different place every night? (viewed 72491 times)
  133. What would you see from inside a black hole? (viewed 71715 times)
  134. Do most astronomers believe in God based on the available scientific evidence? (viewed 71212 times)
  135. Can moons have moons? (viewed 71125 times)
  136. What happens to a substance if its speed is more than the speed of light? (viewed 70580 times)
  137. Why can't you see stars during the day? (viewed 70504 times)
  138. How do rockets move in space? (viewed 70367 times)
  139. How do we weigh objects in space? (viewed 70146 times)
  140. Can you fire a gun on the Moon? (viewed 70068 times)
  141. How often does the Sun pass through a spiral arm in the Milky Way? (viewed 70030 times)
  142. How do astronomers measure the brightness of stars? (viewed 69957 times)
  143. How can the Universe expand faster than the speed of light during inflation? (viewed 69767 times)
  144. What would happen if you took off your helmet in space? (viewed 69608 times)
  145. What are some of the effects of solar flares on Earth? (viewed 69316 times)
  146. Does the Mediterranean sea have tides? (viewed 69292 times)
  147. When the Sun converts mass to energy, do the orbits of the planets change? (viewed 68718 times)
  148. How is astronomy impacted by trigonometry? (viewed 68550 times)
  149. How do we know the mass of the Earth and the Moon? (viewed 68248 times)
  150. Is it possible to measure the temperature of the Sun? (viewed 68178 times)
  151. How does the Sun compare to other stars? (viewed 67225 times)
  152. Why do stars change colour when they twinkle? (viewed 66877 times)
  153. How do you measure a planet's mass? (viewed 66783 times)
  154. What are the "dog days of summer"? (viewed 66543 times)
  155. How does the Moon stay "suspended" in the air? (viewed 66525 times)
  156. How are elements heavier than iron formed? (viewed 65965 times)
  157. What is the evidence supporting the nebula theory of Solar System formation? (viewed 65961 times)
  158. Why do we not have eclipses every month? (viewed 65535 times)
  159. What kinds of jobs do astronomers do? (viewed 65280 times)
  160. Does quantum entanglement imply faster than light communication? (viewed 64838 times)
  161. If the universe is infinite does that mean there is an infinite number of "me"s? (viewed 63959 times)
  162. What are black holes made of? (viewed 63623 times)
  163. What causes seasons? (viewed 63176 times)
  164. How did the stars get named? (viewed 62938 times)
  165. Why doesn't the earliest sunset occur on the shortest day of the year? (viewed 62759 times)
  166. When can I see the Moon through the hole in the Pantheon? (viewed 62689 times)
  167. Where does the name "Moon" come from? (viewed 62527 times)
  168. How did asteroids form and what is the difference between an asteroid and a comet? (viewed 62236 times)
  169. How fast is the Universe expanding? (viewed 62183 times)
  170. How long would it take the Earth to fall into the Sun? (viewed 62133 times)
  171. Where did the matter in the universe come from? (viewed 62053 times)
  172. How do you measure the mass of a star? (viewed 62013 times)
  173. Traveling at light speed, how long would it take to get to the nearest galaxy? (viewed 61857 times)
  174. What are Altitude and Azimuth? (viewed 61584 times)
  175. What's the best college for astronomy? (viewed 61525 times)
  176. Why do planets not twinkle? (viewed 61420 times)
  177. Are there stars outside of galaxies? (viewed 61397 times)
  178. How does light pollution affect astronomers? (viewed 61385 times)
  179. Why doesn't the length of each day change much around the solstices? (viewed 60909 times)
  180. Where, in relation to the entire universe, is the Milky Way located? (viewed 60815 times)
  181. What would happen to us if the sun went out for an hour? (viewed 60761 times)
  182. What is the mass of the Universe? (viewed 59983 times)
  183. What's the difference between dark matter and dark energy? (viewed 59290 times)
  184. How can I calculate the position or path of the Sun for a given time and location? (viewed 58573 times)
  185. Does the Moon rotate? (viewed 58525 times)
  186. Could there be life in the galaxies nearest to the Milky Way? (viewed 58387 times)
  187. Why does the Sun's apparent path through the sky change throughout the year? (viewed 58149 times)
  188. Why does the Earth have only one moon? (viewed 57999 times)
  189. Can any galaxies be seen with the naked eye? (viewed 57670 times)
  190. How does the parachute in a model rocket work? (viewed 57160 times)
  191. How does astronomy benefit humankind? (viewed 57114 times)
  192. What is the origin of spiral structure in galaxies? (viewed 57006 times)
  193. How close was the Moon to the Earth when it formed? (viewed 56807 times)
  194. How long does the supernova stage of a star last? (viewed 56430 times)
  195. What is the shape of the universe? (viewed 56229 times)
  196. What makes up most of the Universe? (viewed 56182 times)
  197. What is the largest structure in the universe? (viewed 55623 times)
  198. Why is looking out into space the same as looking back in time? (viewed 55615 times)
  199. What can we learn from the color of a star? (viewed 55237 times)
  200. Why isn't the summer solstice the hottest day of the year? (viewed 55181 times)
  201. Where are stars born? (viewed 55006 times)
  202. How do astronauts use math in their jobs? (viewed 54766 times)
  203. What is a star's "spectrum"? (viewed 54676 times)
  204. What is the size of a black hole? (viewed 54582 times)
  205. Are names given to black holes? (viewed 54467 times)
  206. Can you see satellites? (viewed 54018 times)
  207. Which constellation does our Sun belong to? (viewed 53837 times)
  208. If gravity is a "curvature of space" rather than a force, why do a ball and bullet follow different paths? (viewed 53819 times)
  209. How do we measure the size of the Moon and of the Sun? (viewed 53520 times)
  210. How do you calculate the azimuth and altitude of an object? (viewed 53467 times)
  211. How do the astronauts communicate in space if sound cannot travel in a vacuum? (viewed 53079 times)
  212. What happens to a bullet fired on the moon? (viewed 52945 times)
  213. Is the Moon seen as a crescent (and not a "boat") all over the world? Is the same phase of the moon visible from the Northern and Southern hemispheres? (viewed 52765 times)
  214. How can I find the distance to the Sun on any given day? (viewed 52672 times)
  215. Are aliens or UFOs real? (viewed 52611 times)
  216. Why do we see stars? (viewed 52487 times)
  217. What other careers involve Astronomy besides Astronomer? (viewed 52471 times)
  218. How can I measure the distance of a star? (viewed 52171 times)
  219. Which hemisphere has the best view of the Milky Way? (viewed 51621 times)
  220. Is the speed of light constant? (viewed 51607 times)
  221. What are some astronomy science fair projects? (viewed 51453 times)
  222. Are there any asteroids on a collision course with Earth? (viewed 51208 times)
  223. How long has there been water on Earth? (viewed 50922 times)
  224. Why is the sky blue and not blue & purple? (viewed 50664 times)
  225. What would happen if the Moon fell out of its orbit around Earth? (viewed 50416 times)
  226. Why is twilight short near the equator? (viewed 50353 times)
  227. Is time travel possible? (viewed 50338 times)
  228. Are meteorites hot or cold when they hit Earth? (viewed 50276 times)
  229. Would your weight change as you go underground? (viewed 50148 times)
  230. Who discovered each planet? (viewed 50124 times)
  231. Why does the Moon look big on the horizon? (viewed 49954 times)
  232. Where did all the water in the universe come from? (viewed 49916 times)
  233. Can we look back far enough in time to see the Big Bang? (viewed 49906 times)
  234. What do a galaxy's colors mean? Are they its true colors? (viewed 49792 times)
  235. If the Earth's rotation period is less than 24 hours, why don't our clocks fall out of sync with the Sun? (viewed 49672 times)
  236. Why is it difficult to understand the expansion of the universe? (viewed 49247 times)
  237. What is a graviton? (viewed 48558 times)
  238. What is the difference between nutation and precession of the Earth? (viewed 48516 times)
  239. How is the time of sunrise calculated? (viewed 48490 times)
  240. What skills do astronomers need? (viewed 48431 times)
  241. What's the difference between astronomy and astrophysics? (viewed 48240 times)
  242. If light has no mass, then what draws it into a black hole? (viewed 48237 times)
  243. Are the planes of solar systems aligned with the plane of the Galaxy? (viewed 48143 times)
  244. How do we know what other planets (and stars, galaxies, etc.) are made of? (viewed 47288 times)
  245. What do I need to do to become an astronomer? (viewed 46639 times)
  246. Do dead stars still shine? (viewed 46304 times)
  247. Why do the size and brightness of the full moon change? (viewed 46185 times)
  248. How do gravitons escape black holes to tell the universe about their gravity? (viewed 46107 times)
  249. Do supermassive black holes cause galaxy rotation? (viewed 46103 times)
  250. What is a wormhole? (viewed 46063 times)
  251. How are black holes discovered? (viewed 45625 times)
  252. Why does the Sun appear larger on the horizon than overhead? (viewed 45325 times)
  253. Where is the nearest black hole? (viewed 45314 times)
  254. Will we get sucked into the black hole at the center of the Milky Way? (viewed 45182 times)
  255. Can we find the place where the Big Bang happened? (viewed 45097 times)
  256. The Moon slows the Earth's rotation, but how fast was it spinning billions of years ago? (viewed 45086 times)
  257. Why can't we see Venus at night when it is an inner planet? (viewed 44857 times)
  258. Why are most months 30 or 31 days long? (viewed 44802 times)
  259. How do galaxies collide in an expanding universe? (viewed 44725 times)
  260. Is the Earth slowly getting larger? (viewed 44719 times)
  261. Why are there stars? (viewed 44666 times)
  262. Can I calculate the size of the Universe by converting light years to kilometres? (viewed 44615 times)
  263. Why does Barnard 68 appear dark? (viewed 44049 times)
  264. Are Kuiper Belt Objects asteroids? Are large Kuiper Belt Objects planets? (viewed 43095 times)
  265. Why don't people walk upside-down on the bottom of the Earth? (viewed 43066 times)
  266. What is the best way to see the Milky Way? (viewed 42554 times)
  267. Could the Universe have expanded faster than the speed of light at the Big Bang? (viewed 42419 times)
  268. Are there eclipses on other planets? (viewed 42376 times)
  269. Was the Sun made in a supernova? (viewed 42361 times)
  270. Did life originate on Earth, or did it come from somewhere else? (viewed 42336 times)
  271. What is the biggest crater recorded on Earth? (viewed 42314 times)
  272. Is there a "South Star"? (viewed 42244 times)
  273. Why does the location of sunrise change? (viewed 42146 times)
  274. Has there been an experiment that measured speed faster than the speed of light in vacuum? (viewed 42142 times)
  275. How long could life on Earth survive if the Sun stopped shining? (viewed 42069 times)
  276. How does Astronomy involve Chemistry? (viewed 42038 times)
  277. Can the acceleration of the Universe be analogous to apparent acceleration in a airplane? (viewed 41952 times)
  278. How much longer will the Earth last? (viewed 41926 times)
  279. Why doesn't dark matter fall into a black hole? (viewed 41846 times)
  280. What is the difference between the "Doppler" redshift and the "gravitational" or "cosmological" redshift? (viewed 41823 times)
  281. How would the weather on Earth be different if it were a cube? (viewed 41711 times)
  282. What happens to spacetime inside a black hole? (viewed 41460 times)
  283. How much can the location of sunset differ from due West? (viewed 41418 times)
  284. Can I buy land on the Moon? (viewed 41405 times)
  285. Is the Moon hollow? (viewed 41132 times)
  286. Why does the Earth only see one side of the Moon? (viewed 41090 times)
  287. What happens when two black holes get too close? (viewed 41064 times)
  288. What's the biggest meteorite? (viewed 40758 times)
  289. What is time dilation? (viewed 40602 times)
  290. What color would Mars be if you were standing on it? (viewed 40541 times)
  291. What are the names of the three stars in Orion's belt? (viewed 40483 times)
  292. What is the most distant known galaxy? (viewed 40378 times)
  293. How can two moons of Saturn share the same orbit? (viewed 40063 times)
  294. What if the Earth rotated twice as fast? (viewed 39927 times)
  295. Could someone travel the universe in his or her own lifetime? (viewed 39691 times)
  296. Can terrestrial planets have rings? (viewed 39575 times)
  297. How long would it take for a mini-black hole to eat the Earth? (viewed 39472 times)
  298. Why do people draw stars with five points? (viewed 39429 times)
  299. How many Astronauts have been in space? (viewed 39266 times)
  300. What are "blue stragglers" in globular clusters? (viewed 39123 times)
  301. How do we feel heat? (viewed 39096 times)
  302. Is it possible to see the full Moon and the Sun simultaneously in high northern latitudes when the Sun doesn't set? (viewed 39094 times)
  303. Why do pictures of distant galaxies have higher resolution than those of nearby planets? (viewed 38840 times)
  304. What is the typical size of a visible shooting star? (viewed 38656 times)
  305. Why can we see the sun's image before sunrise and after sunset? (viewed 38636 times)
  306. If a white dwarf is a "dead" star, why is it so hot? (viewed 38530 times)
  307. How do we know that nuclear fusion is still going on in the Sun? (viewed 38417 times)
  308. Does Mt. Everest cast a shadow on the moon? (viewed 38320 times)
  309. Is the Great Wall the largest galaxy cluster? (viewed 38285 times)
  310. How fast does the Earth go at perihelion and aphelion? (viewed 38239 times)
  311. How does night and day work? (viewed 38145 times)
  312. Does the Sun have an iron surface? (viewed 38000 times)
  313. Why are Saturn's rings flat? (viewed 37953 times)
  314. What is a dimension? (viewed 37897 times)
  315. Can a person go into a black hole and come out alive? (viewed 37883 times)
  316. Can you see the future as you fall into a black hole? (viewed 37810 times)
  317. Do you think it's possible to maintain life on other planets? (viewed 37760 times)
  318. Is the Sun always up for exactly 12 hours at the equator? (viewed 37676 times)
  319. On which days can I see the Moon in the evening / morning and why is this so? (viewed 37662 times)
  320. Can I communicate faster than light? (viewed 37650 times)
  321. What is the speed of gravity? (viewed 37648 times)
  322. Where do planetary rings come from, and what are they made of? (viewed 37609 times)
  323. What is Earthrise over the Moon? (viewed 37369 times)
  324. Why do clocks turn in the opposite direction from the Earth and Moon? (viewed 37351 times)
  325. Who (and when) discovered that the earth's axis is on a 23 degree tilt? (viewed 37340 times)
  326. What can I use for fuel in my homemade rocket? (viewed 37329 times)
  327. How big is the universe? (viewed 37275 times)
  328. Where is the supernova remnant that led to our solar system? (viewed 37247 times)
  329. What is the approximate GPA needed in High School in Math and Science to be an astronomer? (viewed 37141 times)
  330. Are all stars the same? (viewed 37082 times)
  331. How do we determine the age of the universe? (viewed 36937 times)
  332. What companies or businesses can astronomers work for? (viewed 36856 times)
  333. Is there really a 10th planet? (viewed 36781 times)
  334. Why is sea water salty, and not lake water? (viewed 36691 times)
  335. Does the Coriolis force determine which way my toilet drains? Does it affect black holes? (viewed 36403 times)
  336. What would happen to the Earth if an asteroid hit the Moon? (viewed 36375 times)
  337. Is there a beginning and an end to a galaxy's life? (viewed 36340 times)
  338. How many stars can I see? (viewed 36315 times)
  339. How do I tell which planet is which? (viewed 36212 times)
  340. If the universe is 15 billion years old, how can it be larger than 15 billion light years across? (viewed 36211 times)
  341. How can the universe be "flat"? We're 3D! (viewed 36008 times)
  342. How do we know the Milky Way is a spiral galaxy? (viewed 35905 times)
  343. How are photons created and destroyed? (viewed 35797 times)
  344. How do we define distance in an expanding universe? (viewed 35781 times)
  345. Do the Sun's or Earth's magnetic field reverse? (viewed 35759 times)
  346. How can I find my age on another planet? (viewed 35330 times)
  347. Is Andromeda part of the Milky Way? Where can I find them in the sky? (viewed 35093 times)
  348. Why are there blue shifted galaxies? (viewed 35053 times)
  349. Why have star signs shifted by one constellation? (viewed 34941 times)
  350. Why do humans want to go in space? (viewed 34648 times)
  351. How does the brightness of a star depend on its distance from us? (viewed 34619 times)
  352. What was that really big falling star that I saw? (viewed 34530 times)
  353. Can a lunar and a solar eclipse happen in the same month? When will this happen next? (viewed 34520 times)
  354. What is the pattern to the distances between each planet and the sun? (viewed 34500 times)
  355. How are planets detected around other stars? (viewed 34497 times)
  356. What would happen if two stars collided? (viewed 34383 times)
  357. Who came up with the name "black hole"? (viewed 34325 times)
  358. What kind of eyepieces do I need to look at planets? (viewed 34311 times)
  359. What is the significance of the second focus of elliptical orbits of planets in our Solar System? (viewed 34236 times)
  360. How do astronauts communicate with their families from space? (viewed 34194 times)
  361. Will we ever stop having solar eclipses because of the moon's motion away from the Earth? (viewed 34190 times)
  362. How can we estimate the number of Earth-like planets in the Galaxy? (viewed 34172 times)
  363. Is the Earth at the centre of the Universe? (viewed 34122 times)
  364. Is there a simple formula to calculate solar eclipse timings from any position on Earth? (viewed 34078 times)
  365. When we look back to the Big Bang, why don't we see the universe as a tiny speck of matter? (viewed 34065 times)
  366. Why don't astronomers use everyday units to measure distances (what is an AU or a pc)? (viewed 33860 times)
  367. How is it that we see farther out in space (farther back in time) than in the past? (viewed 33715 times)
  368. Will the Moon be invisible in 500 million years? (viewed 33603 times)
  369. Are Earth and the Moon "twin planets"? (viewed 33352 times)
  370. How dangerous are the asteroids? (viewed 33286 times)
  371. How do I become both an astronaut and an astronomer? (viewed 33259 times)
  372. Which American colleges teach astronomy? (viewed 33233 times)
  373. Why is our solar system so different from all the others we've found? (viewed 33184 times)
  374. Why is Uranus tipped on its side? (viewed 33044 times)
  375. How hot is each one of the layers of the sun? (viewed 32935 times)
  376. Can we colonize other planets? (viewed 32908 times)
  377. Why can't a plane fly slowly and let the Earth pass underneath? (viewed 32869 times)
  378. How do sunrise and sunset times change with altitude? (viewed 32572 times)
  379. Can you describe a day on the job as an astronomer? (viewed 32442 times)
  380. What are quasars made of? (viewed 32211 times)
  381. Why do constellations look the same after several years even though all the stars are moving? (viewed 32179 times)
  382. How can I calculate distances between stars? (viewed 32171 times)
  383. Why do astronauts in space need to exercise? (viewed 32043 times)
  384. Why are there no craters on Earth? Did all the meteorites miss us? (viewed 32018 times)
  385. Is it true that the Sun burns off a billion tons of gas every 5 seconds? (viewed 31982 times)
  386. Is the universe really like an expanding balloon? (viewed 31964 times)
  387. Why doesn't gravity change the speed of light? (viewed 31938 times)
  388. Is the Local Group expanding along with the entire Universe? (viewed 31922 times)
  389. Is the gravitational force exerted by the Earth on the Moon equal to the centripetal force acting on the Moon? (viewed 31671 times)
  390. What is dark matter? (viewed 31671 times)
  391. Is it possible to count the stars? (viewed 31637 times)
  392. Is time travel possible using merging black holes? (viewed 31538 times)
  393. Can superheavy elements (such as Z=116 or 118) be formed in a supernova? Can we observe them? (viewed 31461 times)
  394. What is happening just around the black hole in the center of the Milky Way? (viewed 31420 times)
  395. Did the speed of light change over the history of the universe? (viewed 31287 times)
  396. Can we see dead stars with the naked eye? (viewed 31237 times)
  397. How big a change in the Earth's orbit would be required to destroy all life? (viewed 31222 times)
  398. How can we distinguish a star's "real" color from the change in color that we observe due to the star's motion? (viewed 31143 times)
  399. How do we measure distances to other stars? (viewed 31110 times)
  400. How do I make a scale model of the Solar System? (viewed 30953 times)
  401. What happens when an antimatter black hole collides with a matter blackhole? (viewed 30937 times)
  402. Are time machines possible? (viewed 30834 times)
  403. How many moles of stars are in the known universe? (viewed 30492 times)
  404. How are galaxy distances inferred from their recessional velocities? (viewed 30277 times)
  405. How can we tell what the interiors of planets are like? (viewed 30141 times)
  406. Why is the time between two successive full moons different from the lunar synodic month? (viewed 30122 times)
  407. What happens when you change the mass of a White Dwarf or Neutron Star? (viewed 30083 times)
  408. Is there any limitation to what a black hole can "suck" in? (viewed 30008 times)
  409. What do "homogeneity" and "isotropy" mean? (viewed 29919 times)
  410. What is the farthest in space that we have gone? (viewed 29913 times)
  411. Does the Milky Way spin counter-clockwise? If so, do all spiral galaxies spin in this direction and why? (viewed 29809 times)
  412. What would happen if a human were exposed to space without wearing a spacesuit? (viewed 29719 times)
  413. How can we know that there are other galaxies if we cannot leave ours? (viewed 29675 times)
  414. Can astronauts produce water in space? (viewed 29595 times)
  415. What's that dark spot on the Sun? (viewed 29592 times)
  416. Will the seasons change due to precession? (viewed 29577 times)
  417. What are the closest and/or brightest stars? (viewed 29556 times)
  418. How can I tell if the rock I found is a meteorite? (viewed 29532 times)
  419. How was the starting point for the Julian Date system chosen? (viewed 29490 times)
  420. Aren't jobs in astronomy scarce? (viewed 29458 times)
  421. Do astronomers believe in astrology? (viewed 29271 times)
  422. How do we know if the universe will keep expanding forever? (viewed 29268 times)
  423. Why does the SETI project search for radio signals? (viewed 29220 times)
  424. Do we see the same stars from above and below the equator? (viewed 29209 times)
  425. Did I see the Aurora Borealis as a child? (viewed 29185 times)
  426. How long does it take the Big Dipper to move in the sky? (viewed 29163 times)
  427. What are the facts about the Star of Bethlehem? (viewed 29094 times)
  428. Don't tachyons travel faster than light? (viewed 29068 times)
  429. Why do most moons orbit their planets at the equator? (viewed 29033 times)
  430. Why do we study black holes? (viewed 29022 times)
  431. Could an astronaut or satellite fall into a black hole that we didn't know about? (viewed 29001 times)
  432. When are there 5 Sundays in February? (viewed 28955 times)
  433. What are the atmospheres of Mars and Pluto like? (viewed 28911 times)
  434. Wouldn't the Big Bang theory be considered a hypothesis and not a theory? (viewed 28849 times)
  435. Do you believe in UFOs? (viewed 28584 times)
  436. Can you use an infinite line of reflectors to send light to the edge of the Universe? (viewed 28570 times)
  437. What does the term "visible universe" mean? (viewed 28529 times)
  438. Was I hit by a meteorite? (viewed 28510 times)
  439. Has anyone made a map of the Milky Way? (viewed 28509 times)
  440. Could you tell me about the life cycle of galaxies? (viewed 28472 times)
  441. What colors are visible through an amateur telescope? (viewed 28462 times)
  442. How are galaxies named? (viewed 28427 times)
  443. How can geometry be different in space? (viewed 28357 times)
  444. Why are the compositions of comets and asteroids different? (viewed 28072 times)
  445. What's the best thing about being an astronomer? (viewed 27875 times)
  446. Why do so many of the world's UFO sightings happen in America? (viewed 27828 times)
  447. How do asteroids, meteors and comets disappear? (viewed 27790 times)
  448. How much time do astronomers spend looking through telescopes? (viewed 27667 times)
  449. Can two lunar eclipses occur in the same month? (viewed 27622 times)
  450. Will winter and summer constellations change due to abnormal warmth or cold on Earth? (viewed 27613 times)
  451. How do astronomers measure the radius of a star? (viewed 27609 times)
  452. How can we see galaxies if their stars are so faint? (viewed 27454 times)
  453. How will the two black holes that are going to collide affect Earth? (viewed 27449 times)
  454. Have there been other Big Bangs before? (viewed 27426 times)
  455. How do I explain to my children why the Moon has phases? (viewed 27325 times)
  456. How are galaxies and solar systems similar? (viewed 27193 times)
  457. Can life exist on the recently discovered extrasolar planets? (viewed 27191 times)
  458. How close do you have to come to the Earth to be influenced by its gravity? (viewed 27133 times)
  459. What is the origin of the stellar classification system "OBAFGKM"? (viewed 27130 times)
  460. Is the Milky Way a collision of two galaxies? (viewed 27054 times)
  461. Is there a project I can do on black holes? (viewed 27029 times)
  462. How can we measure distances to more stars? (viewed 26932 times)
  463. Do the magnitudes and colors of stars ever change? (viewed 26891 times)
  464. Could you escape from a black hole if you were able to go faster than the speed of light? (viewed 26882 times)
  465. How do scientists slow light down? (viewed 26839 times)
  466. Is infinite temperature possible? (viewed 26644 times)
  467. How close does a supernova need to be to damage the Earth's environment? (viewed 26635 times)
  468. Do we know everything about the Sun? (viewed 26616 times)
  469. Do asteroids hit the sun? (viewed 26610 times)
  470. Can "tired light theory" explain the observed redshifts of galaxies? (viewed 26529 times)
  471. What supernova created the Crab nebula? (viewed 26524 times)
  472. Is it worthwhile to continue the search for extraterrestrial life? (viewed 26485 times)
  473. Can one star orbit another? (viewed 26434 times)
  474. Does the Moon look different in the northern and southern hemispheres? (viewed 26402 times)
  475. Can double stars have planets? (viewed 26390 times)
  476. What causes gamma ray bursts? (viewed 26345 times)
  477. How far does a galaxy extend? (viewed 26293 times)
  478. How do I polar align my telescope? (viewed 26122 times)
  479. What will happen to the Milky Way in the future? (viewed 26086 times)
  480. Can astronauts play musical instruments in space? (viewed 26051 times)
  481. Is there such a thing as hyperspace? (viewed 26024 times)
  482. What type of energy does a black hole have? (viewed 26002 times)
  483. Which way does the sun travel in the southern hemisphere? (viewed 25980 times)
  484. What is sidereal time? (viewed 25967 times)
  485. What happens to the material that has been sucked into a black hole? (viewed 25950 times)
  486. What is the farthest Northern Latitude in which the Magellanic Clouds can be seen? (viewed 25948 times)
  487. Is there oxygen in the atmospheres of other planets? (viewed 25894 times)
  488. Why do the explosions of Type Ia supernovae have a more predictable spectrum than those of regular Type II supernovae? (viewed 25856 times)
  489. Which part of the sky did the famous 'wow' signal originate from? (viewed 25852 times)
  490. What is a Cepheid variable? (viewed 25804 times)
  491. Can a human give birth in space? (viewed 25790 times)
  492. What is "nothing", from a scientific point of view? (viewed 25786 times)
  493. Why did the Pioneer and Voyager take only 2 years to reach Jupiter, while Galileo and Cassini took more than 5 years? (viewed 25738 times)
  494. What's the object I saw that moved across the sky and then got very bright? (viewed 25735 times)
  495. How will a change in the speed of light affect the evolution of the Universe? (viewed 25725 times)
  496. Is there sound coming from the Sun? (viewed 25637 times)
  497. How different would the night sky have looked in 40,000 B.C.? (viewed 25634 times)
  498. How do we know what parameters to use when simulating the collision of the Milky Way and Andromeda? (viewed 25473 times)
  499. Why do we assume that the universe is homogeneous? (viewed 25457 times)
  500. When did people discover that the Sun is a star? (viewed 25428 times)
  501. Why is the shadow on the Moon the shape it is? (viewed 25389 times)
  502. How do we know that sunspots are associated with the Sun's magnetic field? (viewed 25388 times)
  503. When unmanned spacecraft accelerate in space, what causes them to slow down? (viewed 25303 times)
  504. Are planetary nebulae the result of supernovae? (viewed 25300 times)
  505. If we invented special suits could we ever go to the sun? (viewed 25297 times)
  506. Are there any dark stars or dark galaxies made of dark matter? (viewed 25257 times)
  507. What calculations go into predicting eclipses? (viewed 25208 times)
  508. What is the difference between homogeneity and isotropy? (viewed 25181 times)
  509. Was Stonehenge built to mark solar phenomena? (viewed 25145 times)
  510. What is our galaxy's halo made of, and how was it formed? (viewed 25133 times)
  511. Is there a list of the sizes of different kinds of stars? (viewed 25080 times)
  512. What process would bring about a quark star? (viewed 25052 times)
  513. Can I see a quasar? (viewed 25036 times)
  514. What's so exciting about the new planet around 55 Cancri? (viewed 24958 times)
  515. How many sunspots can the Sun have at once? (viewed 24953 times)
  516. Did a giant impact cause the Dark Ages? (viewed 24926 times)
  517. How are asteroid compositions and classifications determined? (viewed 24921 times)
  518. What is a Dyson Sphere? (viewed 24901 times)
  519. Can I see details on Venus? (viewed 24871 times)
  520. Have gravitational waves been proven to exist? (viewed 24868 times)
  521. Can any comparison be made between spiral galaxies and hurricanes? (viewed 24820 times)
  522. Why are there more maria on the near side of the Moon? (viewed 24663 times)
  523. What equipment do I need for astrophotography? (viewed 24615 times)
  524. Why are there active volcanos on Io? (viewed 24589 times)
  525. What happened to all the black holes that were around in the early universe? (viewed 24583 times)
  526. Does Cerenkov radiation travel faster than light? (viewed 24558 times)
  527. How is it proved that the Universe is expanding? (viewed 24553 times)
  528. What happened to the girl who named Pluto? (viewed 24542 times)
  529. Is there any possibility that the Solar System or the Universe is in a black hole? (viewed 24476 times)
  530. Would the biggest airplanes cause tsunamis if they crashed? (viewed 24464 times)
  531. Why are telescopes kept in cold conditions? (viewed 24454 times)
  532. If clocks run slow in a gravitational field, how can we know the true age of the Solar System and Universe? (viewed 24279 times)
  533. How big was the Sun when it first "fired up"? (viewed 24248 times)
  534. How can we compare dark matter and dark energy? (viewed 24227 times)
  535. If the Universe was infinitely dense at the Big Bang, why didn't time stand still? (viewed 24171 times)
  536. What caused Shoemaker-Levy 9 to split up? (viewed 24122 times)
  537. How long do supernova remnants last? (viewed 24106 times)
  538. Why do photos of space taken from space never show any stars? (viewed 24100 times)
  539. Could we send a space mission to a comet? (viewed 24094 times)
  540. How big is the Hubble Ultra Deep Field image? (viewed 24041 times)
  541. How do solar flares affect airline pilots? (viewed 24013 times)
  542. Why doesn't light from distant galaxies reach us instantaneously? (viewed 23973 times)
  543. Could we be seeing dead stars? (viewed 23939 times)
  544. How are sunspots formed? (viewed 23925 times)
  545. Can you give me advice on buying a telescope? (viewed 23864 times)
  546. How does the Earth compare in size to the entire universe at the present epoch? (viewed 23803 times)
  547. Could a different theory of gravity explain the dark matter mystery? (viewed 23797 times)
  548. As the universe expands, why don't galaxies get stretched out? (viewed 23737 times)
  549. Why doesn't NASA build rotating spacecraft to simulate gravity? (viewed 23703 times)
  550. How many comets are currently orbiting our sun? (viewed 23674 times)
  551. Where does the kinetic energy of infalling bodies come from? (viewed 23665 times)
  552. Can I build an instrument to measure the size of the Sun and of the Moon? (viewed 23647 times)
  553. Why is the Hubble Space Telescope in space? (viewed 23605 times)
  554. Can you tell time by the Big Dipper? (viewed 23599 times)
  555. How do we know that superclusters are the largest structures in the universe? (viewed 23491 times)
  556. Did I really hear a meteor? (viewed 23449 times)
  557. How powerful are quasars? (viewed 23438 times)
  558. Why is it important to study meteorites? (viewed 23392 times)
  559. Would extraterrestrial civilizations know that there is life on Earth? (viewed 23368 times)
  560. Why are telescopes located in remote places? (viewed 23311 times)
  561. How is the Cepheid yardstick validated? (viewed 23309 times)
  562. How can I contribute to science as an amateur astronomer? (viewed 23249 times)
  563. Do unmanned spacecraft like Voyager travel in straight lines? (viewed 23214 times)
  564. Did time go slower just after the Big Bang? (viewed 23160 times)
  565. Are the asteroids the remains of a planet which broke apart? (viewed 23147 times)
  566. What would happen if there was a collision between two white dwarfs? (viewed 23138 times)
  567. Are there any new craters on the moon? (viewed 23133 times)
  568. Can supernovae hinder the formation of life in galaxies? (viewed 23117 times)
  569. Do the Earth's magnetic poles ever change places? (viewed 23110 times)
  570. Why are stars of different masses? (viewed 23105 times)
  571. Do galaxies orbit around anything? (viewed 23100 times)
  572. How do planets capture satellites? (viewed 23022 times)
  573. Do similar laws of physics throughout the Universe imply that all life must be like life on Earth? (viewed 23016 times)
  574. How do I become an astronomical artist? (viewed 23004 times)
  575. How do unmanned space probes avoid running into things? (viewed 22988 times)
  576. What kind of instruments are used to detect extrasolar planets? (viewed 22974 times)
  577. How could galaxies have gotten so far away in only 15 billion years? (viewed 22924 times)
  578. Why can't relative velocities add up to more than the speed of light? (viewed 22874 times)
  579. Could there have been multiple Big Bangs at different places in the universe? (viewed 22855 times)
  580. How are astronomy and poetry linked? (viewed 22810 times)
  581. What kind of telescope should I use for astrophotography? (viewed 22785 times)
  582. Could dark energy come from matter anti-matter pairs forming spontaneously and then annihilating? (viewed 22700 times)
  583. Why is NASA shutting down the Hubble Space Telescope? (viewed 22650 times)
  584. Can I listen to the SETI@home radio signal? (viewed 22640 times)
  585. How can you tell if a crescent moon is preceding or following a new-moon phase? (viewed 22598 times)
  586. Does the Sun have any heavy elements? (viewed 22531 times)
  587. Are the properties of extrasolar planets known? (viewed 22515 times)
  588. What class of spiral galaxy is the Milky Way? (viewed 22386 times)
  589. A line drawn perpendicular to a line through the tips of the horns of the crescent moon doesn't point to the Sun! Why not? (viewed 22369 times)
  590. Will we discover an 11th planet? What would it be called? (viewed 22365 times)
  591. Can the theory of formation of the solar system explain all the observables? (viewed 22329 times)
  592. What month was it when Odysseus saw Orion in 1000BC? (viewed 22295 times)
  593. How do astronomers observe the Sun's interior? (viewed 22131 times)
  594. What makes a satellite geosyncronise itself with Earth's orbit? (viewed 22021 times)
  595. Why does one side of Mars look more catastrophic than the other? (viewed 22019 times)
  596. Why does the apparent density of galaxies drop off at larger distances? (viewed 21983 times)
  597. Would a planet near the galactic center have a brighter night sky? (viewed 21922 times)
  598. Where was the water in the big bang? (viewed 21904 times)
  599. Is it possible for amateurs to do optical interferometry? (viewed 21890 times)
  600. Could we send a manned mission to the outer planets? (viewed 21803 times)
  601. What is the solar cycle? (viewed 21732 times)
  602. Do stars' orbits in galaxies obey Kepler's Laws? (viewed 21700 times)
  603. Can other terrestrial moons be (or have been) stable? (viewed 21624 times)
  604. Why was the Platonic year named after Plato? (viewed 21589 times)
  605. How are supernovae discovered? (viewed 21550 times)
  606. How can water be chemically trapped in rocks? (viewed 21501 times)
  607. What would the Big Crunch look like to an observer on Earth? (viewed 21498 times)
  608. Can a black hole come back to the visual universe through a "little bang"? (viewed 21474 times)
  609. Why do spacecraft need heat shields coming back to Earth but not leaving? (viewed 21458 times)
  610. Why are accretion disks flat? (viewed 21443 times)
  611. Does inflation allow for an infinite number of universes? (viewed 21401 times)
  612. What is meant by "stopping down a telescope"? (viewed 21387 times)
  613. Could our position in the universe affect our perceptions of the expansion? (viewed 21352 times)
  614. Why doesn't the hydrogen on Jupiter explode? (viewed 21280 times)
  615. How can the Sun have such a strong gravitational field if it's made of gasses? (viewed 21082 times)
  616. Have astronomers observed any phenomena that could be produced by extraterrestrial civilizations? (viewed 21076 times)
  617. Did I find a rock that came from the Moon? (viewed 21064 times)
  618. What is the SU(3) quark model? (viewed 21027 times)
  619. Can gravitational lensing from intervening galaxies cause the observed ripples in the Cosmic Microwave Background? (viewed 21008 times)
  620. Does a photon observe other photons moving past it at the speed of light? (viewed 20992 times)
  621. Will I be able to see the shadow of the Moon streaking towards me in a total solar eclipse? (viewed 20776 times)
  622. What's new with the Big Bang? (viewed 20735 times)
  623. Could photons be dark matter? (viewed 20654 times)
  624. How can we find galaxies behind the Milky Way? (viewed 20621 times)
  625. Is it possible to build a cheap device to measure declination? (viewed 20605 times)
  626. Why can we have solar eclipses? (viewed 20582 times)
  627. If comets are boiling away, why are there any left? (viewed 20557 times)
  628. Why search for only Earth-like life on other planets? (viewed 20543 times)
  629. How fast do particles travel in space? (viewed 20539 times)
  630. Why do some eclipses take longer than others? (viewed 20480 times)
  631. Where can I find information on the moons of other planets? (viewed 20459 times)
  632. Why is the WMAP picture of the CMB an ellipse? (viewed 20451 times)
  633. How much power is contained in a beam of light? (viewed 20388 times)
  634. Why is pressure broadening greater in low mass stars than in high mass stars? (viewed 20275 times)
  635. What would an "open geometry" for the universe look like? (viewed 20182 times)
  636. What are the boundaries of the constellations? (viewed 20153 times)
  637. Did the Sumerians measure precession? (viewed 20116 times)
  638. What kinds of star clusters are there? (viewed 20062 times)
  639. Why is the Cosmic Microwave Background not absorbed by interstellar hydrogen? (viewed 20014 times)
  640. How do astronomers come up with their facts? (viewed 20001 times)
  641. Why aren't discoveries of extrasolar planets reported on the news? (viewed 19984 times)
  642. Can planets collide with one another? (viewed 19978 times)
  643. How do bars form in spiral galaxies? (viewed 19945 times)
  644. Why don't astronauts sublimate in space? (viewed 19930 times)
  645. How do photons from distant objects maintain enough energy to reach us? (viewed 19906 times)
  646. Do constellations looks the same from space? (viewed 19892 times)
  647. Can HST see the Oort cloud? (viewed 19829 times)
  648. Do electrons age? (viewed 19793 times)
  649. How did Mars get so dusty? (viewed 19730 times)
  650. Can the Space Shuttle abort and return to Earth before reaching orbit? (viewed 19689 times)
  651. Can we make a movie of the Milky Way galaxy's rotation? (viewed 19683 times)
  652. What are collections of galaxies called? (viewed 19595 times)
  653. How long is twilight on the Moon? (viewed 19574 times)
  654. Does the shuttle worry about space junk? (viewed 19506 times)
  655. How does melting a material reset its radioactive clock? (viewed 19472 times)
  656. Will astronauts ever be able to go ice-skating on Europa? (viewed 19469 times)
  657. Why do supernova remnants look like rings rather than spheres? (viewed 19438 times)
  658. Where can I see Newton's original reflecting telescope? (viewed 19388 times)
  659. How do you classify galaxies? (viewed 19381 times)
  660. Why don't all neutron stars become pulsars? (viewed 19346 times)
  661. How can we understand the meaning of large numbers like "a million million?" (viewed 19264 times)
  662. Why doesn't SETI concentrate its observations to the nearby stars and the solar systems that we are discovering? (viewed 19260 times)
  663. What is the best time of the year to see eclipses? (viewed 19242 times)
  664. Will the next generation telescope OWL be able to detect an Earth like extrasolar planet? (viewed 19159 times)
  665. What causes a particle to decay? (viewed 19133 times)
  666. How can I nominate myself for a Nobel Prize in Physics? (viewed 19057 times)
  667. How long has humanity known that we live in a galaxy similar to others in the Universe? (viewed 19018 times)
  668. Will the Leonid meteor shower go away? (viewed 19001 times)
  669. What are "curled" dimensions? (viewed 18886 times)
  670. Is light of different colors affected differently by gravity? (viewed 18840 times)
  671. How does the color index of a star relate to its actual color? (viewed 18776 times)
  672. What was that eclipse I saw in the sky? (viewed 18740 times)
  673. Why is it called astronomy when all the other sciences end in -ology? (viewed 18737 times)
  674. How does interferometry work? (viewed 18721 times)
  675. How do distant galaxies differ from those nearby? (viewed 18643 times)
  676. Does the temperature of matter increase as it is accelerated to relativistic speeds? (viewed 18607 times)
  677. Do asteroids ever do anything good in the Solar System? (viewed 18606 times)
  678. If nothing can escape a black hole, why do some black holes have jets? (viewed 18595 times)
  679. How do we find out about the star formation histories of galaxies? (viewed 18576 times)
  680. Wouldn't the vast distances of space distort SETI signals into unintelligeble forms? (viewed 18522 times)
  681. Can astronomers observe anything when the moon is full? (viewed 18516 times)
  682. What would happen if you went back in time and killed your grandmother? (viewed 18505 times)
  683. What kind of interference must astronomers contend with when observing? (viewed 18501 times)
  684. Are black holes spherical? (viewed 18496 times)
  685. If photons have zero mass, why do they feel the effects of gravity? (viewed 18489 times)
  686. How can I watch the Perseid meteor shower? (viewed 18386 times)
  687. Why will fusion wait until hydrogen is gone before starting to fuse heavier atoms? (viewed 18385 times)
  688. Do we really observe the edges of galaxies at different epochs? (viewed 18336 times)
  689. What do stellar classifications mean? (viewed 18314 times)
  690. Can you tell me the characteristics of W, R, N and S type stars? (viewed 18313 times)
  691. How are astronauts trained for weightlessness? (viewed 18235 times)
  692. What is the three-body problem? (viewed 18174 times)
  693. Why aren't accretion disks around giant stars as hot as accretion disks around black holes? (viewed 18119 times)
  694. If the universe is "bounded" today, could it one day become "unbounded"? (viewed 17968 times)
  695. Will the diameter of a cluster of galaxies change with redshift? (viewed 17946 times)
  696. Is cosmic expansion happening on microscopic scales? (viewed 17780 times)
  697. How can I find out if the new moon has been sighted? (viewed 17659 times)
  698. Could neutrinos be dark matter? (viewed 17466 times)
  699. Do we have to worry about relativity when studying galactic objects? (viewed 17454 times)
  700. What kinds of cancer research have been done in space? (viewed 17290 times)
  701. How does a star take mass from another star? (viewed 17183 times)
  702. When measuring the expansion of the universe, do astronomers consider that they're seeing how galaxies moved long ago, not today? (viewed 17141 times)
  703. Does lunar gardening really work? (viewed 17094 times)
  704. Could the Universe's dark matter be made up of black holes? (viewed 17013 times)
  705. How can you tell the difference between single and multiple extrasolar planets? (viewed 16979 times)
  706. How do supernovae show us that the Universe's expansion is accelerating? (viewed 16972 times)
  707. What is Hot Dark Matter theory? (viewed 16907 times)
  708. Is it a coincidence that we can have total solar eclipses? Are there other planets which also have them? (viewed 16548 times)
  709. Is the green flash real? (viewed 16462 times)
  710. How does libration allow us to see more than 50% of the Moon? (viewed 16414 times)
  711. How can observations of the distant universe prove that the expansion is accelerating *now*? (viewed 16380 times)
  712. How do we know the density of some extrasolar planets? (viewed 16345 times)
  713. What is the photoelectric effect? Why can't multiple low-frequency photons free an electron? (viewed 16344 times)
  714. Is light blueshifted when it is gravitationally lensed? (viewed 16253 times)
  715. Do binary or triple star systems form together? (viewed 16197 times)
  716. No matter how fast the universe is expanding, shouldn't gravity eventually make it recollapse? (viewed 16175 times)
  717. What happens to the helium formed in the sun? (viewed 16119 times)
  718. What percent of the time can astronomers observe without interference from the Moon? (viewed 15953 times)
  719. What do meteorites tell us about life on other planets? (viewed 15896 times)
  720. Why is it easier to see a star if you look slightly to the side? (viewed 15810 times)
  721. Could matter-anti-matter repulsion power the expansion of the universe? (viewed 15682 times)
  722. Can we prove that the Moon isn't hollow? (viewed 15603 times)
  723. If the sun went out and our atmosphere froze solid, what color would it be? (viewed 15584 times)
  724. Why doesn't the ammonia and methane in Jupiter's atmosphere sink into the core? (viewed 15453 times)
  725. Are there any 'lonely galaxies'? (viewed 15295 times)
  726. How do we detect incoming meteorites? (viewed 15214 times)
  727. What was different on Mars in the past to allow liquid water to be present? (viewed 15125 times)
  728. When will Hale-Bopp return? (viewed 14986 times)
  729. Why don't skydivers burn up like meteors? (viewed 14956 times)
  730. Has anyone ever seen a star "turn on"? (viewed 14739 times)
  731. During close approaches, can Mars appear in our sky as large as the Moon? (viewed 14582 times)
  732. How has light from 13 billion years ago not passed us by? (viewed 14458 times)
  733. How are planets affected by the Hot Ionised Medium? (viewed 14375 times)
  734. Why are craters round? (viewed 14315 times)
  735. Can the sun rise from the west on Mars? (viewed 13987 times)
  736. Why was Mir burnt up in the atmosphere? (viewed 13907 times)
  737. What are the largest radio wavelengths observed from radio sources in the sky? (viewed 13901 times)
  738. How can we discern different galaxies/clusters along the same line of sight? (viewed 13816 times)
  739. What is the relationship between the width of a star trail on a photo and the star's intensity? (viewed 13373 times)
  740. What time is sunrise/sunset or moonrise/moonset at my location? (viewed 13309 times)
  741. Can we harvest H & O from space to make water? (viewed 13024 times)
  742. What is between the Oort cloud and the closest star? (viewed 12593 times)
  743. Why does Titan, in spite of being smaller than Mars, have an atmosphere more dense than Earth's? (viewed 12565 times)
  744. The Moon and Sun are the same apparent size in the sky. The Moon is moving away from us at 3.8 centimeters/year. Isn't it improbable that we live in an epoch in which they appear the same size in the sky? (viewed 12011 times)
  745. Could a planetary system survive if its star merged with another, or if its star went supernova? (viewed 11726 times)
  746. Are there solar tides? (viewed 11697 times)
  747. Does weightlessness affect hunger? (viewed 11561 times)
  748. Is Earth-moon tidal friction causing global warming? (viewed 11174 times)
  749. What happens to the Earth as the moon gets farther away and will it ever go away entirely? (viewed 10920 times)
  750. Do planets radiate noise? (viewed 10913 times)
  751. Is the moon spherical? (viewed 10812 times)
  752. Is dark energy affected by black holes? (viewed 10607 times)
  753. What would happen if a nuclear-powered shuttle exploded? (viewed 10492 times)
  754. Why is the Moon higher in the sky in winter and lower in the summer? (viewed 10132 times)
  755. Where are the protons and electrons in a Neutron Star? (viewed 9940 times)
  756. Wait, I'm still confused why information can't travel faster than the speed of light. (viewed 9552 times)
  757. Do more meteorites fall at low latitudes? (viewed 9537 times)
  758. Did the Moon or planets form in a manner similar to that of Earth? (viewed 9527 times)
  759. Is the Moon always visible during winter on the North Pole? (viewed 9472 times)
  760. What are the possible ends of the universe? (viewed 9400 times)
  761. Will Comet Elenin (C/2010 X1) affect the Earth on its close approach in Fall 2011? (viewed 9396 times)
  762. Will the Pioneer and Voyager probes ever leave the Milky Way? (viewed 9349 times)
  763. Is it sensible to consider terraforming Mars? (viewed 9274 times)
  764. If there are infinity universes, will every thing that is possible happen? (viewed 9273 times)
  765. What color are meteors? (viewed 8866 times)
  766. Where is everybody? (viewed 8515 times)
  767. Why does Mars have a dusty atmosphere? (viewed 8057 times)
  768. The naming of Mars (viewed 7952 times)
  769. If I were traveling through space, could I see distant galaxies with my own eyes? (viewed 7905 times)
  770. Does the singularity in a black hole create a new Universe? (viewed 7870 times)
  771. Is the reddish dust of Mars biogenic? (viewed 7720 times)
  772. Where is the Spitzer Space Telescope? (viewed 7142 times)
  773. When will humans travel to Mars and revisit the Moon? (viewed 7048 times)
  774. Does the particles involved in a star's final core collapse travel faster than the speed of light? (viewed 6387 times)
  775. How likely is it for a planet to transit its star? (viewed 6211 times)
  776. When is the best time to observe zodiacal light? (viewed 6165 times)
  777. What causes the aurora? (viewed 6024 times)
  778. Why do astronomers use telescopes? (viewed 6016 times)
  779. How did a transit of Venus provide astronomers with the first measurement of the Earth-Sun distance? (viewed 5014 times)
  780. Can the Sun be closer to the Earth than any planet is to Earth? (viewed 4358 times)
  781. Cosmologists say the expansion of the universe is accelerating, what is driving this? (viewed 3803 times)
  782. Can we hear sound on Titan? (viewed 3697 times)
  783. Does the direction of the moon's crescent change through the night? (viewed 3508 times)
  784. What do all the angles in a table for a planet's orbit mean? (viewed 3291 times)
  785. How do I maximize my chances of seeing shooting stars? (viewed 2655 times)
  786. Are exoplanets real? (viewed 2327 times)
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