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 2142775 times)
  2. What color is each planet? (viewed 934479 times)
  3. At what speed does the earth move around the sun? (viewed 603389 times)
  4. Is the Moon moving away from the Earth? When was this discovered? (viewed 581979 times)
  5. How far is each planet from Earth? (viewed 480618 times)
  6. When will Halley's Comet return? (viewed 434761 times)
  7. How long does it take for the Sun's light to reach us? (viewed 398877 times)
  8. How many stars are there in our Galaxy (Milky Way)? (viewed 392486 times)
  9. Why do the planets orbit the sun? (viewed 392296 times)
  10. What is the universe expanding into? (viewed 377476 times)
  11. How do you measure the distance between Earth and the Sun? (viewed 352131 times)
  12. Which planets have rings? (viewed 325711 times)
  13. Why do stars twinkle? (viewed 324953 times)
  14. Does the Moon rotate? Are there other moons that always keep one face toward their planet? (viewed 307635 times)
  15. How do I build a model rocket? (viewed 293445 times)
  16. Can you hear sounds in space? (viewed 289768 times)
  17. What color is Venus? (viewed 276870 times)
  18. What is a white hole? (viewed 271112 times)
  19. What are the different kinds of astronomers? (viewed 254851 times)
  20. What is the life cycle of a star? (viewed 248022 times)
  21. What is that ring (or rainbow) around the moon? (viewed 243326 times)
  22. What are the names of the earth, moon, sun, and solar system? (viewed 243233 times)
  23. What makes the Earth rotate? (viewed 239455 times)
  24. What are shooting stars? (viewed 234650 times)
  25. What is the largest star? (viewed 222833 times)
  26. How do we know the age of the Universe and the Earth? (viewed 219610 times)
  27. Can artificial gravity be created in space? (viewed 218602 times)
  28. What do astronauts eat in space? Can they grow food? (viewed 215008 times)
  29. Why do planets rotate? (viewed 213921 times)
  30. Is the universe expanding faster than the speed of light? (viewed 210769 times)
  31. How does the location of sunrise and sunset change throughout the year? (viewed 205869 times)
  32. How can we see the Milky Way if we are inside it? (viewed 189878 times)
  33. Where did the name 'Earth' come from? (viewed 182938 times)
  34. What would happen if we did not have a Moon? (viewed 179327 times)
  35. Why is a day divided into 24 hours? (viewed 178612 times)
  36. How does the position of Moonrise and Moonset change? (viewed 178221 times)
  37. Why isn't the sky bright at night if the universe has so many stars? (viewed 176220 times)
  38. How many Earths fit into the Sun? (viewed 174328 times)
  39. Who named the planets and who decides what to name them? (viewed 166142 times)
  40. Why do airplanes take longer to fly West than East? (viewed 166107 times)
  41. When was the last time all 9 planets were aligned? (viewed 164020 times)
  42. Why are the Moon and Sun sometimes orange or red? (viewed 161313 times)
  43. Is the distance from the Earth to the Sun changing? (viewed 153586 times)
  44. What is at the end of the Universe? (viewed 152084 times)
  45. Is Pluto a planet? (viewed 152078 times)
  46. How can I find the star I have "bought"? (viewed 151159 times)
  47. How much money is spent on space exploration? (viewed 147951 times)
  48. What is a nova? (viewed 142455 times)
  49. Does your weight change between the poles and the equator? (viewed 138964 times)
  50. How do astronauts take baths and use restrooms in space? (viewed 137376 times)
  51. Can we feel the Earth spin? (viewed 135045 times)
  52. What direction do planets rotate? (viewed 132934 times)
  53. Why are there both high and low tides? (viewed 132333 times)
  54. Is the Sun expanding? Will it ever explode? (viewed 130900 times)
  55. Do stars move in the sky? (viewed 128820 times)
  56. What is the largest galaxy? (viewed 127966 times)
  57. How many known galaxies are there? (viewed 126857 times)
  58. What are the advantages and disadvantages of using a telescope in space? (viewed 124615 times)
  59. Why do all the planets orbit in the same plane? (viewed 124182 times)
  60. How are light and heavy elements formed? (viewed 119878 times)
  61. Can I buy a star? (viewed 119771 times)
  62. What is the physical difference between a star and a planet? (viewed 118834 times)
  63. Will the sun go supernova in six years and destroy Earth (as seen on Yahoo)? (viewed 116668 times)
  64. Why do planets have elliptical orbits? (viewed 116479 times)
  65. Are there telescopes that can see the flag and lunar rover on the Moon? (viewed 116318 times)
  66. Why hasn't NASA gone back to the moon? (viewed 116080 times)
  67. Who first measured the speed of light? (viewed 114643 times)
  68. Does the Sun have a scientific name? (viewed 114505 times)
  69. How do stars move in the Galaxy? (viewed 114023 times)
  70. What happens when galaxies collide? (viewed 113448 times)
  71. What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (viewed 112670 times)
  72. How do rockets work? (viewed 112368 times)
  73. What is the hottest time of day? (viewed 112333 times)
  74. What is the size of the Solar System? (viewed 110480 times)
  75. Does evolution contradict the second law of thermodynamics? (viewed 109700 times)
  76. What would happen if an impact caused Earth to stop rotating? (viewed 109489 times)
  77. How much money do astronomers make? (viewed 109464 times)
  78. What will happen to life on Earth when the Sun becomes a red giant? (viewed 108646 times)
  79. How do you calculate the lifetime of the Sun? (viewed 108464 times)
  80. What was there before the Big Bang and what is there outside of our universe? (viewed 108123 times)
  81. Will the magnetic field of the Earth reverse its direction in the future? Will this cause problems? (viewed 108107 times)
  82. What do astronauts do all day in the International Space Station? (viewed 107539 times)
  83. When is the next comet due to arrive? (viewed 107498 times)
  84. What elements make up the Sun? (viewed 106852 times)
  85. How long does a solar eclipse last? (viewed 106340 times)
  86. Do black holes die? If so how? (viewed 105856 times)
  87. What is the observational difference between a star and a planet? (viewed 105507 times)
  88. How many constellations are there? (viewed 104828 times)
  89. Does gravity vary across the surface of the Earth? (viewed 104208 times)
  90. What would happen if the gravity on Earth was suddenly turned off? (viewed 103622 times)
  91. What's the difference between astronomy and astrology? (viewed 103398 times)
  92. Does the Sun rotate? (viewed 102455 times)
  93. What are constellations used for? (viewed 101081 times)
  94. Does the Sun move around the Milky Way? (viewed 100464 times)
  95. How many meteorites hit Earth each year? (viewed 99264 times)
  96. Which planet is most similar to Earth? (viewed 98127 times)
  97. What is apparent magnitude? (viewed 98034 times)
  98. Why do different stars appear with seasons? (viewed 97999 times)
  99. What kind of schooling is necessary to become an astronomer? (viewed 97461 times)
  100. If Mars is only about 35-60 million miles away at close approach, why does it take 6-8 months to get there? (viewed 93733 times)
  101. How do astronomers use math in their jobs? (viewed 93706 times)
  102. Is there a proof that Earth moves? (viewed 93310 times)
  103. How critical is the Earth-Sun distance in maintaining our average temperatures on Earth? (viewed 91929 times)
  104. Where did the Universe come from? (viewed 91835 times)
  105. Does the Sun orbit the Earth as well as the Earth orbiting the Sun? (viewed 91696 times)
  106. Why are stars and planets round? (viewed 91648 times)
  107. Why is the Universe flat and not spherical? (viewed 91522 times)
  108. What is the difference between a "star" and a "sun"? (viewed 91125 times)
  109. How can a star burn with no oxygen? (viewed 90941 times)
  110. Why is the Moon so bright? (viewed 90787 times)
  111. What is a singularity? (viewed 90176 times)
  112. What makes the wind? (viewed 90156 times)
  113. What would happen if an asteroid 10 kilometers across hit the Earth? (viewed 89473 times)
  114. What are the requirements for being a planet? (viewed 88785 times)
  115. Have astronomers discovered Earth's second moon? (viewed 88520 times)
  116. Why does the Earth tilt back and forward once a year? (viewed 85109 times)
  117. What are RA and DEC? (viewed 84877 times)
  118. Where does the name "Milky Way" come from? (viewed 84216 times)
  119. Since Earth is spinning, why do we land in the same place when we jump or fall? (viewed 84141 times)
  120. Considering the motion of the Earth, the solar system, and the galaxy, how fast am I moving while lying in bed asleep? (viewed 82849 times)
  121. How many stars are born and die each day? (viewed 82235 times)
  122. What would happen if Earth had more than one moon? (viewed 82219 times)
  123. Why aren't there any green stars? (viewed 80147 times)
  124. Why is the moon in a different place every night? (viewed 80082 times)
  125. What kind of rock is the moon made of? (viewed 78942 times)
  126. How are galaxies formed? (viewed 78658 times)
  127. Did astronauts really go to the Moon, or is it a hoax? (viewed 78579 times)
  128. How do we weigh objects in space? (viewed 77841 times)
  129. Will the Sun become a black hole one day? (viewed 76915 times)
  130. What is the density of a black hole? (viewed 76512 times)
  131. How are black holes made? Could one be made close to us? (viewed 76054 times)
  132. What would happen if a supermassive black hole came close to the Earth? (viewed 75891 times)
  133. How do rockets move in space? (viewed 74550 times)
  134. Can moons have moons? (viewed 74374 times)
  135. What happens to a substance if its speed is more than the speed of light? (viewed 74182 times)
  136. Who has landed on the moon? (viewed 74110 times)
  137. Do most astronomers believe in God based on the available scientific evidence? (viewed 73952 times)
  138. What would happen if you took off your helmet in space? (viewed 73849 times)
  139. Why can't you see stars during the day? (viewed 73822 times)
  140. What is the evidence supporting the nebula theory of Solar System formation? (viewed 73678 times)
  141. What would you see from inside a black hole? (viewed 73638 times)
  142. Does the Mediterranean sea have tides? (viewed 73530 times)
  143. When the Sun converts mass to energy, do the orbits of the planets change? (viewed 73398 times)
  144. How do astronomers measure the brightness of stars? (viewed 73271 times)
  145. How often does the Sun pass through a spiral arm in the Milky Way? (viewed 73188 times)
  146. What are some of the effects of solar flares on Earth? (viewed 72410 times)
  147. How can the Universe expand faster than the speed of light during inflation? (viewed 72380 times)
  148. Why do we not have eclipses every month? (viewed 72243 times)
  149. How do we know the mass of the Earth and the Moon? (viewed 72109 times)
  150. Can you fire a gun on the Moon? (viewed 72041 times)
  151. How is astronomy impacted by trigonometry? (viewed 71383 times)
  152. How do you measure a planet's mass? (viewed 70866 times)
  153. Is it possible to measure the temperature of the Sun? (viewed 70760 times)
  154. How does the Moon stay "suspended" in the air? (viewed 70392 times)
  155. How are elements heavier than iron formed? (viewed 70173 times)
  156. Why do stars change colour when they twinkle? (viewed 70008 times)
  157. How does the Sun compare to other stars? (viewed 69594 times)
  158. What are the "dog days of summer"? (viewed 67745 times)
  159. Does quantum entanglement imply faster than light communication? (viewed 67018 times)
  160. What kinds of jobs do astronomers do? (viewed 66508 times)
  161. If the universe is infinite does that mean there is an infinite number of "me"s? (viewed 65954 times)
  162. How long would it take the Earth to fall into the Sun? (viewed 65834 times)
  163. How does light pollution affect astronomers? (viewed 65727 times)
  164. Where does the name "Moon" come from? (viewed 65508 times)
  165. How do you measure the mass of a star? (viewed 65315 times)
  166. How did the stars get named? (viewed 65213 times)
  167. Why doesn't the earliest sunset occur on the shortest day of the year? (viewed 64993 times)
  168. Where did the matter in the universe come from? (viewed 64978 times)
  169. What are black holes made of? (viewed 64804 times)
  170. Are there stars outside of galaxies? (viewed 64659 times)
  171. Traveling at light speed, how long would it take to get to the nearest galaxy? (viewed 64576 times)
  172. What are Altitude and Azimuth? (viewed 64526 times)
  173. How did asteroids form and what is the difference between an asteroid and a comet? (viewed 64390 times)
  174. What causes seasons? (viewed 64294 times)
  175. How fast is the Universe expanding? (viewed 63597 times)
  176. When can I see the Moon through the hole in the Pantheon? (viewed 63382 times)
  177. Where, in relation to the entire universe, is the Milky Way located? (viewed 62921 times)
  178. What's the difference between dark matter and dark energy? (viewed 62833 times)
  179. Why do planets not twinkle? (viewed 62794 times)
  180. What's the best college for astronomy? (viewed 62601 times)
  181. What would happen to us if the sun went out for an hour? (viewed 62236 times)
  182. Why doesn't the length of each day change much around the solstices? (viewed 62063 times)
  183. Why is looking out into space the same as looking back in time? (viewed 61953 times)
  184. Why does the Sun's apparent path through the sky change throughout the year? (viewed 61666 times)
  185. How does astronomy benefit humankind? (viewed 61303 times)
  186. What is the mass of the Universe? (viewed 61162 times)
  187. What can we learn from the color of a star? (viewed 60566 times)
  188. How can I calculate the position or path of the Sun for a given time and location? (viewed 60460 times)
  189. How does the parachute in a model rocket work? (viewed 60041 times)
  190. What is the origin of spiral structure in galaxies? (viewed 59864 times)
  191. Why does the Earth have only one moon? (viewed 59821 times)
  192. Does the Moon rotate? (viewed 59716 times)
  193. Could there be life in the galaxies nearest to the Milky Way? (viewed 59573 times)
  194. Can any galaxies be seen with the naked eye? (viewed 59469 times)
  195. How close was the Moon to the Earth when it formed? (viewed 59457 times)
  196. What makes up most of the Universe? (viewed 58748 times)
  197. How long does the supernova stage of a star last? (viewed 58736 times)
  198. How do the astronauts communicate in space if sound cannot travel in a vacuum? (viewed 58585 times)
  199. If gravity is a "curvature of space" rather than a force, why do a ball and bullet follow different paths? (viewed 57417 times)
  200. What is the shape of the universe? (viewed 57036 times)
  201. What is a star's "spectrum"? (viewed 56791 times)
  202. How do astronauts use math in their jobs? (viewed 56710 times)
  203. Why isn't the summer solstice the hottest day of the year? (viewed 56707 times)
  204. What is the largest structure in the universe? (viewed 56054 times)
  205. What happens to a bullet fired on the moon? (viewed 55955 times)
  206. How do we measure the size of the Moon and of the Sun? (viewed 55921 times)
  207. What is the size of a black hole? (viewed 55881 times)
  208. How do you calculate the azimuth and altitude of an object? (viewed 55852 times)
  209. 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 55757 times)
  210. Where are stars born? (viewed 55586 times)
  211. Which constellation does our Sun belong to? (viewed 55316 times)
  212. Are names given to black holes? (viewed 55056 times)
  213. Can you see satellites? (viewed 54744 times)
  214. How can I find the distance to the Sun on any given day? (viewed 54740 times)
  215. Where did all the water in the universe come from? (viewed 54497 times)
  216. What other careers involve Astronomy besides Astronomer? (viewed 54084 times)
  217. Which hemisphere has the best view of the Milky Way? (viewed 54067 times)
  218. Why do we see stars? (viewed 53811 times)
  219. Why is twilight short near the equator? (viewed 53695 times)
  220. Are aliens or UFOs real? (viewed 53489 times)
  221. How can I measure the distance of a star? (viewed 53354 times)
  222. Is the speed of light constant? (viewed 53184 times)
  223. Are meteorites hot or cold when they hit Earth? (viewed 53060 times)
  224. What do a galaxy's colors mean? Are they its true colors? (viewed 52942 times)
  225. Why is the sky blue and not blue & purple? (viewed 52828 times)
  226. Are there any asteroids on a collision course with Earth? (viewed 52760 times)
  227. How long has there been water on Earth? (viewed 52613 times)
  228. Would your weight change as you go underground? (viewed 52386 times)
  229. What would happen if the Moon fell out of its orbit around Earth? (viewed 52293 times)
  230. What are some astronomy science fair projects? (viewed 52107 times)
  231. Can we look back far enough in time to see the Big Bang? (viewed 51623 times)
  232. How is the time of sunrise calculated? (viewed 51328 times)
  233. Why does the Moon look big on the horizon? (viewed 51220 times)
  234. How do we know what other planets (and stars, galaxies, etc.) are made of? (viewed 51195 times)
  235. Is time travel possible? (viewed 51157 times)
  236. What skills do astronomers need? (viewed 51120 times)
  237. Who discovered each planet? (viewed 51079 times)
  238. If the Earth's rotation period is less than 24 hours, why don't our clocks fall out of sync with the Sun? (viewed 51053 times)
  239. Are the planes of solar systems aligned with the plane of the Galaxy? (viewed 50999 times)
  240. What is the difference between nutation and precession of the Earth? (viewed 50522 times)
  241. Why is it difficult to understand the expansion of the universe? (viewed 50114 times)
  242. What's the difference between astronomy and astrophysics? (viewed 50090 times)
  243. What is a graviton? (viewed 49790 times)
  244. If light has no mass, then what draws it into a black hole? (viewed 49444 times)
  245. Why are most months 30 or 31 days long? (viewed 48649 times)
  246. Why do the size and brightness of the full moon change? (viewed 48415 times)
  247. Can the acceleration of the Universe be analogous to apparent acceleration in a airplane? (viewed 48265 times)
  248. Do supermassive black holes cause galaxy rotation? (viewed 48100 times)
  249. What do I need to do to become an astronomer? (viewed 47751 times)
  250. Can we find the place where the Big Bang happened? (viewed 47669 times)
  251. Why does the Sun appear larger on the horizon than overhead? (viewed 47594 times)
  252. How do gravitons escape black holes to tell the universe about their gravity? (viewed 47536 times)
  253. What is a wormhole? (viewed 47420 times)
  254. How are black holes discovered? (viewed 47362 times)
  255. Do dead stars still shine? (viewed 47194 times)
  256. The Moon slows the Earth's rotation, but how fast was it spinning billions of years ago? (viewed 47009 times)
  257. Why don't people walk upside-down on the bottom of the Earth? (viewed 46567 times)
  258. Why are there stars? (viewed 46541 times)
  259. Is the Earth slowly getting larger? (viewed 46302 times)
  260. Will we get sucked into the black hole at the center of the Milky Way? (viewed 46166 times)
  261. Why can't we see Venus at night when it is an inner planet? (viewed 46071 times)
  262. Where is the nearest black hole? (viewed 45872 times)
  263. How do galaxies collide in an expanding universe? (viewed 45822 times)
  264. Did life originate on Earth, or did it come from somewhere else? (viewed 45591 times)
  265. Why does Barnard 68 appear dark? (viewed 45499 times)
  266. Are Kuiper Belt Objects asteroids? Are large Kuiper Belt Objects planets? (viewed 45330 times)
  267. Can I calculate the size of the Universe by converting light years to kilometres? (viewed 45319 times)
  268. Are there eclipses on other planets? (viewed 44518 times)
  269. Could the Universe have expanded faster than the speed of light at the Big Bang? (viewed 44023 times)
  270. How does Astronomy involve Chemistry? (viewed 44007 times)
  271. What is the difference between the "Doppler" redshift and the "gravitational" or "cosmological" redshift? (viewed 43935 times)
  272. Is there a "South Star"? (viewed 43933 times)
  273. How long could life on Earth survive if the Sun stopped shining? (viewed 43931 times)
  274. Why does the location of sunrise change? (viewed 43930 times)
  275. How much can the location of sunset differ from due West? (viewed 43862 times)
  276. What is the best way to see the Milky Way? (viewed 43819 times)
  277. Has there been an experiment that measured speed faster than the speed of light in vacuum? (viewed 43644 times)
  278. How would the weather on Earth be different if it were a cube? (viewed 43473 times)
  279. What happens to spacetime inside a black hole? (viewed 43373 times)
  280. Was the Sun made in a supernova? (viewed 43007 times)
  281. Why doesn't dark matter fall into a black hole? (viewed 42868 times)
  282. What is the biggest crater recorded on Earth? (viewed 42793 times)
  283. How much longer will the Earth last? (viewed 42693 times)
  284. What are the names of the three stars in Orion's belt? (viewed 42402 times)
  285. Why does the Earth only see one side of the Moon? (viewed 42005 times)
  286. Can I buy land on the Moon? (viewed 41910 times)
  287. What if the Earth rotated twice as fast? (viewed 41737 times)
  288. What happens when two black holes get too close? (viewed 41674 times)
  289. Is the Moon hollow? (viewed 41649 times)
  290. Why do people draw stars with five points? (viewed 41411 times)
  291. Why can we see the sun's image before sunrise and after sunset? (viewed 41381 times)
  292. How do we feel heat? (viewed 41275 times)
  293. What color would Mars be if you were standing on it? (viewed 41275 times)
  294. What is time dilation? (viewed 41254 times)
  295. What's the biggest meteorite? (viewed 41101 times)
  296. Could someone travel the universe in his or her own lifetime? (viewed 41019 times)
  297. How can two moons of Saturn share the same orbit? (viewed 40962 times)
  298. Is it possible to see the full Moon and the Sun simultaneously in high northern latitudes when the Sun doesn't set? (viewed 40925 times)
  299. What is the most distant known galaxy? (viewed 40847 times)
  300. Is the Sun always up for exactly 12 hours at the equator? (viewed 40707 times)
  301. Can terrestrial planets have rings? (viewed 40621 times)
  302. How fast does the Earth go at perihelion and aphelion? (viewed 40475 times)
  303. Why do clocks turn in the opposite direction from the Earth and Moon? (viewed 40308 times)
  304. How do we know that nuclear fusion is still going on in the Sun? (viewed 40284 times)
  305. What are "blue stragglers" in globular clusters? (viewed 40227 times)
  306. Do you think it's possible to maintain life on other planets? (viewed 40187 times)
  307. How do we define distance in an expanding universe? (viewed 40036 times)
  308. How long would it take for a mini-black hole to eat the Earth? (viewed 40035 times)
  309. How many Astronauts have been in space? (viewed 39935 times)
  310. Does the Sun have an iron surface? (viewed 39858 times)
  311. Why are Saturn's rings flat? (viewed 39782 times)
  312. Why do pictures of distant galaxies have higher resolution than those of nearby planets? (viewed 39634 times)
  313. If a white dwarf is a "dead" star, why is it so hot? (viewed 39588 times)
  314. What is the typical size of a visible shooting star? (viewed 39394 times)
  315. Can you see the future as you fall into a black hole? (viewed 39372 times)
  316. Who (and when) discovered that the earth's axis is on a 23 degree tilt? (viewed 39358 times)
  317. Can a person go into a black hole and come out alive? (viewed 39341 times)
  318. On which days can I see the Moon in the evening / morning and why is this so? (viewed 39258 times)
  319. Is the Great Wall the largest galaxy cluster? (viewed 39083 times)
  320. What is a dimension? (viewed 39076 times)
  321. Does Mt. Everest cast a shadow on the moon? (viewed 38998 times)
  322. Are all stars the same? (viewed 38798 times)
  323. How does night and day work? (viewed 38761 times)
  324. Where do planetary rings come from, and what are they made of? (viewed 38740 times)
  325. Can I communicate faster than light? (viewed 38571 times)
  326. How do we determine the age of the universe? (viewed 38489 times)
  327. What companies or businesses can astronomers work for? (viewed 38278 times)
  328. How can the universe be "flat"? We're 3D! (viewed 38264 times)
  329. Why can't a plane fly slowly and let the Earth pass underneath? (viewed 38263 times)
  330. What is the speed of gravity? (viewed 38220 times)
  331. What is Earthrise over the Moon? (viewed 38166 times)
  332. What is the approximate GPA needed in High School in Math and Science to be an astronomer? (viewed 37981 times)
  333. Where is the supernova remnant that led to our solar system? (viewed 37845 times)
  334. What can I use for fuel in my homemade rocket? (viewed 37631 times)
  335. How big is the universe? (viewed 37615 times)
  336. How do we know the Milky Way is a spiral galaxy? (viewed 37592 times)
  337. Is there a beginning and an end to a galaxy's life? (viewed 37590 times)
  338. How are photons created and destroyed? (viewed 37535 times)
  339. Why is sea water salty, and not lake water? (viewed 37530 times)
  340. If the universe is 15 billion years old, how can it be larger than 15 billion light years across? (viewed 37523 times)
  341. Is there really a 10th planet? (viewed 37438 times)
  342. Does the Coriolis force determine which way my toilet drains? Does it affect black holes? (viewed 37228 times)
  343. Why are there blue shifted galaxies? (viewed 37186 times)
  344. What would happen to the Earth if an asteroid hit the Moon? (viewed 36889 times)
  345. How many stars can I see? (viewed 36780 times)
  346. How do I tell which planet is which? (viewed 36617 times)
  347. How are planets detected around other stars? (viewed 36540 times)
  348. What kind of eyepieces do I need to look at planets? (viewed 36515 times)
  349. How can I find my age on another planet? (viewed 36300 times)
  350. How does the brightness of a star depend on its distance from us? (viewed 36294 times)
  351. Do the Sun's or Earth's magnetic field reverse? (viewed 36224 times)
  352. What is the pattern to the distances between each planet and the sun? (viewed 36197 times)
  353. Can a lunar and a solar eclipse happen in the same month? When will this happen next? (viewed 36144 times)
  354. Why do humans want to go in space? (viewed 36080 times)
  355. Will we ever stop having solar eclipses because of the moon's motion away from the Earth? (viewed 35892 times)
  356. Why have star signs shifted by one constellation? (viewed 35855 times)
  357. What is the significance of the second focus of elliptical orbits of planets in our Solar System? (viewed 35842 times)
  358. Can you describe a day on the job as an astronomer? (viewed 35777 times)
  359. Is Andromeda part of the Milky Way? Where can I find them in the sky? (viewed 35706 times)
  360. How hot is each one of the layers of the sun? (viewed 35609 times)
  361. Who came up with the name "black hole"? (viewed 35276 times)
  362. How do astronauts communicate with their families from space? (viewed 35265 times)
  363. How can we estimate the number of Earth-like planets in the Galaxy? (viewed 35152 times)
  364. What would happen if two stars collided? (viewed 34991 times)
  365. What was that really big falling star that I saw? (viewed 34917 times)
  366. Is the Local Group expanding along with the entire Universe? (viewed 34909 times)
  367. Is the Earth at the centre of the Universe? (viewed 34720 times)
  368. Is there a simple formula to calculate solar eclipse timings from any position on Earth? (viewed 34717 times)
  369. How do I become both an astronaut and an astronomer? (viewed 34631 times)
  370. Why don't astronomers use everyday units to measure distances (what is an AU or a pc)? (viewed 34608 times)
  371. When we look back to the Big Bang, why don't we see the universe as a tiny speck of matter? (viewed 34583 times)
  372. How is it that we see farther out in space (farther back in time) than in the past? (viewed 34577 times)
  373. Will the Moon be invisible in 500 million years? (viewed 34250 times)
  374. How do sunrise and sunset times change with altitude? (viewed 34089 times)
  375. Why is Uranus tipped on its side? (viewed 33886 times)
  376. Why is our solar system so different from all the others we've found? (viewed 33830 times)
  377. Are Earth and the Moon "twin planets"? (viewed 33759 times)
  378. How dangerous are the asteroids? (viewed 33727 times)
  379. Which American colleges teach astronomy? (viewed 33698 times)
  380. Is it true that the Sun burns off a billion tons of gas every 5 seconds? (viewed 33375 times)
  381. Why do constellations look the same after several years even though all the stars are moving? (viewed 33374 times)
  382. Is the universe really like an expanding balloon? (viewed 33306 times)
  383. Can we colonize other planets? (viewed 33297 times)
  384. Why are there no craters on Earth? Did all the meteorites miss us? (viewed 33148 times)
  385. Is the gravitational force exerted by the Earth on the Moon equal to the centripetal force acting on the Moon? (viewed 33057 times)
  386. Why do astronauts in space need to exercise? (viewed 32827 times)
  387. What are quasars made of? (viewed 32711 times)
  388. How can I calculate distances between stars? (viewed 32648 times)
  389. Can superheavy elements (such as Z=116 or 118) be formed in a supernova? Can we observe them? (viewed 32496 times)
  390. What is dark matter? (viewed 32384 times)
  391. Why doesn't gravity change the speed of light? (viewed 32353 times)
  392. Does the Milky Way spin counter-clockwise? If so, do all spiral galaxies spin in this direction and why? (viewed 32134 times)
  393. Why is the time between two successive full moons different from the lunar synodic month? (viewed 32076 times)
  394. How big a change in the Earth's orbit would be required to destroy all life? (viewed 32029 times)
  395. Do we see the same stars from above and below the equator? (viewed 32021 times)
  396. Is it possible to count the stars? (viewed 31977 times)
  397. Can we see dead stars with the naked eye? (viewed 31861 times)
  398. Is time travel possible using merging black holes? (viewed 31843 times)
  399. What is happening just around the black hole in the center of the Milky Way? (viewed 31808 times)
  400. How do we measure distances to other stars? (viewed 31787 times)
  401. What would happen if a human were exposed to space without wearing a spacesuit? (viewed 31772 times)
  402. Did the speed of light change over the history of the universe? (viewed 31764 times)
  403. How do I make a scale model of the Solar System? (viewed 31644 times)
  404. How can we distinguish a star's "real" color from the change in color that we observe due to the star's motion? (viewed 31622 times)
  405. How can we tell what the interiors of planets are like? (viewed 31575 times)
  406. What happens when an antimatter black hole collides with a matter blackhole? (viewed 31438 times)
  407. What do "homogeneity" and "isotropy" mean? (viewed 31420 times)
  408. Does the Moon look different in the northern and southern hemispheres? (viewed 31353 times)
  409. Are time machines possible? (viewed 31164 times)
  410. What happens when you change the mass of a White Dwarf or Neutron Star? (viewed 31136 times)
  411. How many moles of stars are in the known universe? (viewed 31065 times)
  412. How are galaxy distances inferred from their recessional velocities? (viewed 30956 times)
  413. What is the farthest in space that we have gone? (viewed 30873 times)
  414. Will the seasons change due to precession? (viewed 30656 times)
  415. Can astronauts produce water in space? (viewed 30597 times)
  416. How was the starting point for the Julian Date system chosen? (viewed 30509 times)
  417. How do we know if the universe will keep expanding forever? (viewed 30498 times)
  418. How can we know that there are other galaxies if we cannot leave ours? (viewed 30495 times)
  419. Is there any limitation to what a black hole can "suck" in? (viewed 30301 times)
  420. Aren't jobs in astronomy scarce? (viewed 30273 times)
  421. Why does the SETI project search for radio signals? (viewed 30179 times)
  422. What are the closest and/or brightest stars? (viewed 30166 times)
  423. How can I tell if the rock I found is a meteorite? (viewed 30095 times)
  424. Why do we study black holes? (viewed 30055 times)
  425. How long does it take the Big Dipper to move in the sky? (viewed 30034 times)
  426. What's that dark spot on the Sun? (viewed 29968 times)
  427. Do astronomers believe in astrology? (viewed 29955 times)
  428. Did I see the Aurora Borealis as a child? (viewed 29749 times)
  429. When are there 5 Sundays in February? (viewed 29747 times)
  430. Do you believe in UFOs? (viewed 29670 times)
  431. What are the facts about the Star of Bethlehem? (viewed 29670 times)
  432. Why do most moons orbit their planets at the equator? (viewed 29620 times)
  433. Can you use an infinite line of reflectors to send light to the edge of the Universe? (viewed 29610 times)
  434. Wouldn't the Big Bang theory be considered a hypothesis and not a theory? (viewed 29581 times)
  435. Don't tachyons travel faster than light? (viewed 29456 times)
  436. What are the atmospheres of Mars and Pluto like? (viewed 29448 times)
  437. Could an astronaut or satellite fall into a black hole that we didn't know about? (viewed 29289 times)
  438. What does the term "visible universe" mean? (viewed 29282 times)
  439. Could you tell me about the life cycle of galaxies? (viewed 29243 times)
  440. What colors are visible through an amateur telescope? (viewed 29115 times)
  441. Why do so many of the world's UFO sightings happen in America? (viewed 29024 times)
  442. Why are the compositions of comets and asteroids different? (viewed 28915 times)
  443. How can geometry be different in space? (viewed 28888 times)
  444. How are galaxies named? (viewed 28852 times)
  445. Was I hit by a meteorite? (viewed 28851 times)
  446. Has anyone made a map of the Milky Way? (viewed 28814 times)
  447. What is the origin of the stellar classification system "OBAFGKM"? (viewed 28787 times)
  448. What's the best thing about being an astronomer? (viewed 28667 times)
  449. Can two lunar eclipses occur in the same month? (viewed 28617 times)
  450. How do astronomers measure the radius of a star? (viewed 28602 times)
  451. How do asteroids, meteors and comets disappear? (viewed 28429 times)
  452. How much time do astronomers spend looking through telescopes? (viewed 28105 times)
  453. How do I explain to my children why the Moon has phases? (viewed 28073 times)
  454. Will winter and summer constellations change due to abnormal warmth or cold on Earth? (viewed 28020 times)
  455. How can we see galaxies if their stars are so faint? (viewed 27987 times)
  456. How are galaxies and solar systems similar? (viewed 27848 times)
  457. Have there been other Big Bangs before? (viewed 27829 times)
  458. Do asteroids hit the sun? (viewed 27769 times)
  459. How will the two black holes that are going to collide affect Earth? (viewed 27742 times)
  460. Do the magnitudes and colors of stars ever change? (viewed 27649 times)
  461. Is there a project I can do on black holes? (viewed 27581 times)
  462. How close do you have to come to the Earth to be influenced by its gravity? (viewed 27557 times)
  463. Can a human give birth in space? (viewed 27545 times)
  464. How can we measure distances to more stars? (viewed 27441 times)
  465. Can life exist on the recently discovered extrasolar planets? (viewed 27415 times)
  466. Is the Milky Way a collision of two galaxies? (viewed 27364 times)
  467. Could you escape from a black hole if you were able to go faster than the speed of light? (viewed 27333 times)
  468. How do scientists slow light down? (viewed 27249 times)
  469. What causes gamma ray bursts? (viewed 27179 times)
  470. What supernova created the Crab nebula? (viewed 27142 times)
  471. Is it worthwhile to continue the search for extraterrestrial life? (viewed 27088 times)
  472. How close does a supernova need to be to damage the Earth's environment? (viewed 27086 times)
  473. Is there oxygen in the atmospheres of other planets? (viewed 27076 times)
  474. Can "tired light theory" explain the observed redshifts of galaxies? (viewed 27029 times)
  475. Can double stars have planets? (viewed 27026 times)
  476. Is infinite temperature possible? (viewed 27025 times)
  477. Which part of the sky did the famous 'wow' signal originate from? (viewed 26939 times)
  478. Do we know everything about the Sun? (viewed 26930 times)
  479. Why did the Pioneer and Voyager take only 2 years to reach Jupiter, while Galileo and Cassini took more than 5 years? (viewed 26780 times)
  480. Can one star orbit another? (viewed 26775 times)
  481. How far does a galaxy extend? (viewed 26622 times)
  482. Can astronauts play musical instruments in space? (viewed 26596 times)
  483. What will happen to the Milky Way in the future? (viewed 26575 times)
  484. What is sidereal time? (viewed 26533 times)
  485. Which way does the sun travel in the southern hemisphere? (viewed 26469 times)
  486. How do I polar align my telescope? (viewed 26456 times)
  487. What type of energy does a black hole have? (viewed 26387 times)
  488. When did people discover that the Sun is a star? (viewed 26383 times)
  489. Is there sound coming from the Sun? (viewed 26379 times)
  490. Are planetary nebulae the result of supernovae? (viewed 26359 times)
  491. What is a Cepheid variable? (viewed 26351 times)
  492. What is the farthest Northern Latitude in which the Magellanic Clouds can be seen? (viewed 26319 times)
  493. How different would the night sky have looked in 40,000 B.C.? (viewed 26287 times)
  494. Is there such a thing as hyperspace? (viewed 26282 times)
  495. What's the object I saw that moved across the sky and then got very bright? (viewed 26280 times)
  496. What is "nothing", from a scientific point of view? (viewed 26280 times)
  497. What happens to the material that has been sucked into a black hole? (viewed 26239 times)
  498. Why do the explosions of Type Ia supernovae have a more predictable spectrum than those of regular Type II supernovae? (viewed 26176 times)
  499. Why is the shadow on the Moon the shape it is? (viewed 26141 times)
  500. How will a change in the speed of light affect the evolution of the Universe? (viewed 26042 times)
  501. What is our galaxy's halo made of, and how was it formed? (viewed 26041 times)
  502. When unmanned spacecraft accelerate in space, what causes them to slow down? (viewed 25937 times)
  503. Why do we assume that the universe is homogeneous? (viewed 25927 times)
  504. If we invented special suits could we ever go to the sun? (viewed 25861 times)
  505. How do we know that sunspots are associated with the Sun's magnetic field? (viewed 25838 times)
  506. What is the difference between homogeneity and isotropy? (viewed 25817 times)
  507. How do we know what parameters to use when simulating the collision of the Milky Way and Andromeda? (viewed 25781 times)
  508. What calculations go into predicting eclipses? (viewed 25661 times)
  509. Are there any dark stars or dark galaxies made of dark matter? (viewed 25654 times)
  510. How are asteroid compositions and classifications determined? (viewed 25602 times)
  511. How big is the Hubble Ultra Deep Field image? (viewed 25558 times)
  512. Can I see a quasar? (viewed 25551 times)
  513. How many sunspots can the Sun have at once? (viewed 25495 times)
  514. Is there a list of the sizes of different kinds of stars? (viewed 25463 times)
  515. What happened to the girl who named Pluto? (viewed 25445 times)
  516. Was Stonehenge built to mark solar phenomena? (viewed 25428 times)
  517. Why are there more maria on the near side of the Moon? (viewed 25406 times)
  518. What process would bring about a quark star? (viewed 25398 times)
  519. Can I see details on Venus? (viewed 25362 times)
  520. Can any comparison be made between spiral galaxies and hurricanes? (viewed 25356 times)
  521. What's so exciting about the new planet around 55 Cancri? (viewed 25253 times)
  522. What happened to all the black holes that were around in the early universe? (viewed 25245 times)
  523. Did a giant impact cause the Dark Ages? (viewed 25244 times)
  524. Would the biggest airplanes cause tsunamis if they crashed? (viewed 25242 times)
  525. Why are telescopes kept in cold conditions? (viewed 25146 times)
  526. Have gravitational waves been proven to exist? (viewed 25144 times)
  527. What is a Dyson Sphere? (viewed 25131 times)
  528. If clocks run slow in a gravitational field, how can we know the true age of the Solar System and Universe? (viewed 25116 times)
  529. What equipment do I need for astrophotography? (viewed 25093 times)
  530. How is it proved that the Universe is expanding? (viewed 25081 times)
  531. Does Cerenkov radiation travel faster than light? (viewed 24957 times)
  532. Why are there active volcanos on Io? (viewed 24922 times)
  533. If the Universe was infinitely dense at the Big Bang, why didn't time stand still? (viewed 24849 times)
  534. Is there any possibility that the Solar System or the Universe is in a black hole? (viewed 24798 times)
  535. How long do supernova remnants last? (viewed 24634 times)
  536. How can we compare dark matter and dark energy? (viewed 24601 times)
  537. How do unmanned space probes avoid running into things? (viewed 24590 times)
  538. How big was the Sun when it first "fired up"? (viewed 24550 times)
  539. Can you give me advice on buying a telescope? (viewed 24519 times)
  540. How do solar flares affect airline pilots? (viewed 24486 times)
  541. How can I contribute to science as an amateur astronomer? (viewed 24459 times)
  542. What caused Shoemaker-Levy 9 to split up? (viewed 24455 times)
  543. Why do photos of space taken from space never show any stars? (viewed 24442 times)
  544. Could we send a space mission to a comet? (viewed 24431 times)
  545. Why is it important to study meteorites? (viewed 24423 times)
  546. Why doesn't light from distant galaxies reach us instantaneously? (viewed 24368 times)
  547. Why are telescopes located in remote places? (viewed 24327 times)
  548. Why doesn't NASA build rotating spacecraft to simulate gravity? (viewed 24324 times)
  549. How are sunspots formed? (viewed 24318 times)
  550. Can I build an instrument to measure the size of the Sun and of the Moon? (viewed 24280 times)
  551. How does the Earth compare in size to the entire universe at the present epoch? (viewed 24279 times)
  552. Could a different theory of gravity explain the dark matter mystery? (viewed 24187 times)
  553. Are the asteroids the remains of a planet which broke apart? (viewed 24174 times)
  554. Where does the kinetic energy of infalling bodies come from? (viewed 24160 times)
  555. Could we be seeing dead stars? (viewed 24147 times)
  556. As the universe expands, why don't galaxies get stretched out? (viewed 24099 times)
  557. Did I really hear a meteor? (viewed 24067 times)
  558. How many comets are currently orbiting our sun? (viewed 23991 times)
  559. Can you tell time by the Big Dipper? (viewed 23911 times)
  560. Why is the Hubble Space Telescope in space? (viewed 23829 times)
  561. Why can't relative velocities add up to more than the speed of light? (viewed 23753 times)
  562. Would extraterrestrial civilizations know that there is life on Earth? (viewed 23743 times)
  563. Do the Earth's magnetic poles ever change places? (viewed 23743 times)
  564. How do we know that superclusters are the largest structures in the universe? (viewed 23729 times)
  565. How is the Cepheid yardstick validated? (viewed 23716 times)
  566. Do unmanned spacecraft like Voyager travel in straight lines? (viewed 23709 times)
  567. How powerful are quasars? (viewed 23670 times)
  568. Do galaxies orbit around anything? (viewed 23624 times)
  569. How could galaxies have gotten so far away in only 15 billion years? (viewed 23595 times)
  570. Did time go slower just after the Big Bang? (viewed 23581 times)
  571. Why are stars of different masses? (viewed 23566 times)
  572. What kind of instruments are used to detect extrasolar planets? (viewed 23496 times)
  573. Are there any new craters on the moon? (viewed 23484 times)
  574. Can supernovae hinder the formation of life in galaxies? (viewed 23468 times)
  575. How do I become an astronomical artist? (viewed 23433 times)
  576. What would happen if there was a collision between two white dwarfs? (viewed 23419 times)
  577. Do similar laws of physics throughout the Universe imply that all life must be like life on Earth? (viewed 23374 times)
  578. How do planets capture satellites? (viewed 23366 times)
  579. How are astronomy and poetry linked? (viewed 23325 times)
  580. Could there have been multiple Big Bangs at different places in the universe? (viewed 23319 times)
  581. What kind of telescope should I use for astrophotography? (viewed 23314 times)
  582. How do astronomers observe the Sun's interior? (viewed 23300 times)
  583. Could dark energy come from matter anti-matter pairs forming spontaneously and then annihilating? (viewed 23149 times)
  584. Why is NASA shutting down the Hubble Space Telescope? (viewed 23041 times)
  585. Can I listen to the SETI@home radio signal? (viewed 23034 times)
  586. How can you tell if a crescent moon is preceding or following a new-moon phase? (viewed 23018 times)
  587. Does the Sun have any heavy elements? (viewed 22943 times)
  588. 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 22890 times)
  589. Can the theory of formation of the solar system explain all the observables? (viewed 22869 times)
  590. What class of spiral galaxy is the Milky Way? (viewed 22849 times)
  591. Are the properties of extrasolar planets known? (viewed 22772 times)
  592. Will we discover an 11th planet? What would it be called? (viewed 22745 times)
  593. Where was the water in the big bang? (viewed 22631 times)
  594. Could we send a manned mission to the outer planets? (viewed 22614 times)
  595. Why do spacecraft need heat shields coming back to Earth but not leaving? (viewed 22593 times)
  596. What month was it when Odysseus saw Orion in 1000BC? (viewed 22578 times)
  597. How can water be chemically trapped in rocks? (viewed 22504 times)
  598. Is it possible for amateurs to do optical interferometry? (viewed 22482 times)
  599. What makes a satellite geosyncronise itself with Earth's orbit? (viewed 22437 times)
  600. Why does the apparent density of galaxies drop off at larger distances? (viewed 22350 times)
  601. Why does one side of Mars look more catastrophic than the other? (viewed 22275 times)
  602. Would a planet near the galactic center have a brighter night sky? (viewed 22226 times)
  603. Do stars' orbits in galaxies obey Kepler's Laws? (viewed 22191 times)
  604. Why are accretion disks flat? (viewed 22088 times)
  605. Why was the Platonic year named after Plato? (viewed 21929 times)
  606. Can other terrestrial moons be (or have been) stable? (viewed 21918 times)
  607. How can the Sun have such a strong gravitational field if it's made of gasses? (viewed 21913 times)
  608. What is the solar cycle? (viewed 21865 times)
  609. What would the Big Crunch look like to an observer on Earth? (viewed 21839 times)
  610. How are supernovae discovered? (viewed 21776 times)
  611. What is meant by "stopping down a telescope"? (viewed 21713 times)
  612. Can a black hole come back to the visual universe through a "little bang"? (viewed 21670 times)
  613. Why doesn't the hydrogen on Jupiter explode? (viewed 21642 times)
  614. Does inflation allow for an infinite number of universes? (viewed 21639 times)
  615. Could our position in the universe affect our perceptions of the expansion? (viewed 21578 times)
  616. Did I find a rock that came from the Moon? (viewed 21413 times)
  617. Have astronomers observed any phenomena that could be produced by extraterrestrial civilizations? (viewed 21381 times)
  618. What is the SU(3) quark model? (viewed 21335 times)
  619. Can gravitational lensing from intervening galaxies cause the observed ripples in the Cosmic Microwave Background? (viewed 21278 times)
  620. Will I be able to see the shadow of the Moon streaking towards me in a total solar eclipse? (viewed 21275 times)
  621. Does a photon observe other photons moving past it at the speed of light? (viewed 21189 times)
  622. Can planets collide with one another? (viewed 21108 times)
  623. How can we find galaxies behind the Milky Way? (viewed 21040 times)
  624. Could photons be dark matter? (viewed 21031 times)
  625. What's new with the Big Bang? (viewed 21010 times)
  626. How fast do particles travel in space? (viewed 21001 times)
  627. Why is the WMAP picture of the CMB an ellipse? (viewed 20974 times)
  628. Do constellations looks the same from space? (viewed 20951 times)
  629. Why search for only Earth-like life on other planets? (viewed 20912 times)
  630. Why can we have solar eclipses? (viewed 20896 times)
  631. Is it possible to build a cheap device to measure declination? (viewed 20889 times)
  632. Where can I find information on the moons of other planets? (viewed 20840 times)
  633. If comets are boiling away, why are there any left? (viewed 20829 times)
  634. How much power is contained in a beam of light? (viewed 20816 times)
  635. Why do some eclipses take longer than others? (viewed 20724 times)
  636. If photons have zero mass, why do they feel the effects of gravity? (viewed 20710 times)
  637. Why is pressure broadening greater in low mass stars than in high mass stars? (viewed 20619 times)
  638. What are collections of galaxies called? (viewed 20572 times)
  639. Did the Sumerians measure precession? (viewed 20508 times)
  640. What are the boundaries of the constellations? (viewed 20480 times)
  641. What would an "open geometry" for the universe look like? (viewed 20464 times)
  642. What kinds of star clusters are there? (viewed 20431 times)
  643. How did Mars get so dusty? (viewed 20338 times)
  644. How do photons from distant objects maintain enough energy to reach us? (viewed 20271 times)
  645. Why don't astronauts sublimate in space? (viewed 20239 times)
  646. How do bars form in spiral galaxies? (viewed 20226 times)
  647. Why aren't discoveries of extrasolar planets reported on the news? (viewed 20224 times)
  648. Why is the Cosmic Microwave Background not absorbed by interstellar hydrogen? (viewed 20208 times)
  649. How do astronomers come up with their facts? (viewed 20200 times)
  650. Do electrons age? (viewed 20063 times)
  651. Can HST see the Oort cloud? (viewed 20026 times)
  652. Can we make a movie of the Milky Way galaxy's rotation? (viewed 19981 times)
  653. Will astronauts ever be able to go ice-skating on Europa? (viewed 19888 times)
  654. Why don't all neutron stars become pulsars? (viewed 19886 times)
  655. How does melting a material reset its radioactive clock? (viewed 19881 times)
  656. Can the Space Shuttle abort and return to Earth before reaching orbit? (viewed 19880 times)
  657. How long is twilight on the Moon? (viewed 19874 times)
  658. Does the shuttle worry about space junk? (viewed 19758 times)
  659. Where can I see Newton's original reflecting telescope? (viewed 19738 times)
  660. How do you classify galaxies? (viewed 19707 times)
  661. Why do supernova remnants look like rings rather than spheres? (viewed 19687 times)
  662. How does the color index of a star relate to its actual color? (viewed 19673 times)
  663. How can we understand the meaning of large numbers like "a million million?" (viewed 19649 times)
  664. Why is it called astronomy when all the other sciences end in -ology? (viewed 19632 times)
  665. What is the best time of the year to see eclipses? (viewed 19524 times)
  666. What causes a particle to decay? (viewed 19515 times)
  667. Why doesn't SETI concentrate its observations to the nearby stars and the solar systems that we are discovering? (viewed 19506 times)
  668. Are black holes spherical? (viewed 19491 times)
  669. Will the next generation telescope OWL be able to detect an Earth like extrasolar planet? (viewed 19453 times)
  670. If nothing can escape a black hole, why do some black holes have jets? (viewed 19413 times)
  671. How can I nominate myself for a Nobel Prize in Physics? (viewed 19348 times)
  672. How long has humanity known that we live in a galaxy similar to others in the Universe? (viewed 19314 times)
  673. Will the Leonid meteor shower go away? (viewed 19267 times)
  674. What are "curled" dimensions? (viewed 19177 times)
  675. Do asteroids ever do anything good in the Solar System? (viewed 19089 times)
  676. Is light of different colors affected differently by gravity? (viewed 19062 times)
  677. What would happen if you went back in time and killed your grandmother? (viewed 19045 times)
  678. How does interferometry work? (viewed 19031 times)
  679. How do distant galaxies differ from those nearby? (viewed 18982 times)
  680. What kind of interference must astronomers contend with when observing? (viewed 18950 times)
  681. What happens to the helium formed in the sun? (viewed 18914 times)
  682. Does the temperature of matter increase as it is accelerated to relativistic speeds? (viewed 18913 times)
  683. What was that eclipse I saw in the sky? (viewed 18912 times)
  684. Wouldn't the vast distances of space distort SETI signals into unintelligeble forms? (viewed 18846 times)
  685. How do we find out about the star formation histories of galaxies? (viewed 18824 times)
  686. Why will fusion wait until hydrogen is gone before starting to fuse heavier atoms? (viewed 18808 times)
  687. How can I watch the Perseid meteor shower? (viewed 18734 times)
  688. What do stellar classifications mean? (viewed 18717 times)
  689. Can astronomers observe anything when the moon is full? (viewed 18690 times)
  690. Why aren't accretion disks around giant stars as hot as accretion disks around black holes? (viewed 18644 times)
  691. Do we really observe the edges of galaxies at different epochs? (viewed 18637 times)
  692. How are astronauts trained for weightlessness? (viewed 18583 times)
  693. Can you tell me the characteristics of W, R, N and S type stars? (viewed 18564 times)
  694. What is the three-body problem? (viewed 18516 times)
  695. When measuring the expansion of the universe, do astronomers consider that they're seeing how galaxies moved long ago, not today? (viewed 18317 times)
  696. If the universe is "bounded" today, could it one day become "unbounded"? (viewed 18297 times)
  697. How do supernovae show us that the Universe's expansion is accelerating? (viewed 18274 times)
  698. Will the diameter of a cluster of galaxies change with redshift? (viewed 18239 times)
  699. Is cosmic expansion happening on microscopic scales? (viewed 18101 times)
  700. Does lunar gardening really work? (viewed 17863 times)
  701. How can I find out if the new moon has been sighted? (viewed 17848 times)
  702. Could neutrinos be dark matter? (viewed 17824 times)
  703. Do we have to worry about relativity when studying galactic objects? (viewed 17705 times)
  704. What kinds of cancer research have been done in space? (viewed 17564 times)
  705. How does a star take mass from another star? (viewed 17428 times)
  706. Could the Universe's dark matter be made up of black holes? (viewed 17400 times)
  707. What time is sunrise/sunset or moonrise/moonset at my location? (viewed 17361 times)
  708. How can you tell the difference between single and multiple extrasolar planets? (viewed 17200 times)
  709. What is Hot Dark Matter theory? (viewed 17193 times)
  710. How do we know the density of some extrasolar planets? (viewed 17046 times)
  711. Is it a coincidence that we can have total solar eclipses? Are there other planets which also have them? (viewed 17026 times)
  712. What is the photoelectric effect? Why can't multiple low-frequency photons free an electron? (viewed 16940 times)
  713. Is the green flash real? (viewed 16889 times)
  714. 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 16688 times)
  715. How does libration allow us to see more than 50% of the Moon? (viewed 16662 times)
  716. How can observations of the distant universe prove that the expansion is accelerating *now*? (viewed 16614 times)
  717. Do binary or triple star systems form together? (viewed 16521 times)
  718. Is light blueshifted when it is gravitationally lensed? (viewed 16514 times)
  719. No matter how fast the universe is expanding, shouldn't gravity eventually make it recollapse? (viewed 16414 times)
  720. What do meteorites tell us about life on other planets? (viewed 16375 times)
  721. Can we prove that the Moon isn't hollow? (viewed 16316 times)
  722. Why is it easier to see a star if you look slightly to the side? (viewed 16310 times)
  723. How has light from 13 billion years ago not passed us by? (viewed 16284 times)
  724. If the sun went out and our atmosphere froze solid, what color would it be? (viewed 16222 times)
  725. What percent of the time can astronomers observe without interference from the Moon? (viewed 16157 times)
  726. Could matter-anti-matter repulsion power the expansion of the universe? (viewed 15906 times)
  727. Why doesn't the ammonia and methane in Jupiter's atmosphere sink into the core? (viewed 15866 times)
  728. What was different on Mars in the past to allow liquid water to be present? (viewed 15783 times)
  729. Why don't skydivers burn up like meteors? (viewed 15712 times)
  730. How do we detect incoming meteorites? (viewed 15702 times)
  731. When will Hale-Bopp return? (viewed 15650 times)
  732. Are there any 'lonely galaxies'? (viewed 15534 times)
  733. Has anyone ever seen a star "turn on"? (viewed 15492 times)
  734. Why are craters round? (viewed 15210 times)
  735. During close approaches, can Mars appear in our sky as large as the Moon? (viewed 14741 times)
  736. Can the sun rise from the west on Mars? (viewed 14586 times)
  737. How are planets affected by the Hot Ionised Medium? (viewed 14582 times)
  738. What are the largest radio wavelengths observed from radio sources in the sky? (viewed 14200 times)
  739. Why was Mir burnt up in the atmosphere? (viewed 14146 times)
  740. How can we discern different galaxies/clusters along the same line of sight? (viewed 14005 times)
  741. Why does Titan, in spite of being smaller than Mars, have an atmosphere more dense than Earth's? (viewed 13710 times)
  742. Can we harvest H & O from space to make water? (viewed 13641 times)
  743. What is the relationship between the width of a star trail on a photo and the star's intensity? (viewed 13604 times)
  744. What is between the Oort cloud and the closest star? (viewed 13027 times)
  745. What happens to the Earth as the moon gets farther away and will it ever go away entirely? (viewed 12642 times)
  746. Could a planetary system survive if its star merged with another, or if its star went supernova? (viewed 12152 times)
  747. Are there solar tides? (viewed 12025 times)
  748. Does weightlessness affect hunger? (viewed 11757 times)
  749. Is Earth-moon tidal friction causing global warming? (viewed 11710 times)
  750. Why is the Moon higher in the sky in winter and lower in the summer? (viewed 11647 times)
  751. Is the moon spherical? (viewed 11542 times)
  752. Do planets radiate noise? (viewed 11474 times)
  753. Is the Moon always visible during winter on the North Pole? (viewed 11292 times)
  754. Is dark energy affected by black holes? (viewed 11241 times)
  755. Where are the protons and electrons in a Neutron Star? (viewed 11129 times)
  756. What would happen if a nuclear-powered shuttle exploded? (viewed 10787 times)
  757. Wait, I'm still confused why information can't travel faster than the speed of light. (viewed 10499 times)
  758. Will the Pioneer and Voyager probes ever leave the Milky Way? (viewed 9930 times)
  759. Do more meteorites fall at low latitudes? (viewed 9852 times)
  760. Will Comet Elenin (C/2010 X1) affect the Earth on its close approach in Fall 2011? (viewed 9842 times)
  761. Did the Moon or planets form in a manner similar to that of Earth? (viewed 9794 times)
  762. What are the possible ends of the universe? (viewed 9791 times)
  763. If there are infinity universes, will every thing that is possible happen? (viewed 9585 times)
  764. Is it sensible to consider terraforming Mars? (viewed 9475 times)
  765. What color are meteors? (viewed 9277 times)
  766. Where is everybody? (viewed 8748 times)
  767. Why does Mars have a dusty atmosphere? (viewed 8481 times)
  768. Does the singularity in a black hole create a new Universe? (viewed 8297 times)
  769. The naming of Mars (viewed 8271 times)
  770. If I were traveling through space, could I see distant galaxies with my own eyes? (viewed 8254 times)
  771. Is the reddish dust of Mars biogenic? (viewed 8149 times)
  772. Why do astronomers use telescopes? (viewed 7937 times)
  773. Where is the Spitzer Space Telescope? (viewed 7566 times)
  774. When will humans travel to Mars and revisit the Moon? (viewed 7226 times)
  775. How likely is it for a planet to transit its star? (viewed 6928 times)
  776. What causes the aurora? (viewed 6797 times)
  777. Does the particles involved in a star's final core collapse travel faster than the speed of light? (viewed 6570 times)
  778. When is the best time to observe zodiacal light? (viewed 6428 times)
  779. How did a transit of Venus provide astronomers with the first measurement of the Earth-Sun distance? (viewed 5556 times)
  780. Can the Sun be closer to the Earth than any planet is to Earth? (viewed 5039 times)
  781. Cosmologists say the expansion of the universe is accelerating, what is driving this? (viewed 4305 times)
  782. Can we hear sound on Titan? (viewed 4053 times)
  783. Does the direction of the moon's crescent change through the night? (viewed 3900 times)
  784. What do all the angles in a table for a planet's orbit mean? (viewed 3767 times)
  785. How do I maximize my chances of seeing shooting stars? (viewed 3248 times)
  786. Are exoplanets real? (viewed 2731 times)
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