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 2127013 times)
  2. What color is each planet? (viewed 899989 times)
  3. At what speed does the earth move around the sun? (viewed 575198 times)
  4. Is the Moon moving away from the Earth? When was this discovered? (viewed 554130 times)
  5. How far is each planet from Earth? (viewed 464445 times)
  6. When will Halley's Comet return? (viewed 419154 times)
  7. How many stars are there in our Galaxy (Milky Way)? (viewed 386550 times)
  8. How long does it take for the Sun's light to reach us? (viewed 386397 times)
  9. Why do the planets orbit the sun? (viewed 373476 times)
  10. What is the universe expanding into? (viewed 367977 times)
  11. How do you measure the distance between Earth and the Sun? (viewed 336848 times)
  12. Which planets have rings? (viewed 321357 times)
  13. Why do stars twinkle? (viewed 316863 times)
  14. Does the Moon rotate? Are there other moons that always keep one face toward their planet? (viewed 299184 times)
  15. How do I build a model rocket? (viewed 288635 times)
  16. What color is Venus? (viewed 272062 times)
  17. What is a white hole? (viewed 265839 times)
  18. Can you hear sounds in space? (viewed 255057 times)
  19. What is the life cycle of a star? (viewed 245142 times)
  20. What are the names of the earth, moon, sun, and solar system? (viewed 236914 times)
  21. What makes the Earth rotate? (viewed 229731 times)
  22. What is that ring (or rainbow) around the moon? (viewed 228998 times)
  23. What are shooting stars? (viewed 227391 times)
  24. What is the largest star? (viewed 221527 times)
  25. What do astronauts eat in space? Can they grow food? (viewed 208248 times)
  26. How do we know the age of the Universe and the Earth? (viewed 205137 times)
  27. Why do planets rotate? (viewed 204312 times)
  28. Can artificial gravity be created in space? (viewed 204154 times)
  29. What are the different kinds of astronomers? (viewed 202514 times)
  30. Is the universe expanding faster than the speed of light? (viewed 199604 times)
  31. How does the location of sunrise and sunset change throughout the year? (viewed 190471 times)
  32. How can we see the Milky Way if we are inside it? (viewed 179447 times)
  33. Where did the name 'Earth' come from? (viewed 179302 times)
  34. What would happen if we did not have a Moon? (viewed 174627 times)
  35. Why isn't the sky bright at night if the universe has so many stars? (viewed 173655 times)
  36. How many Earths fit into the Sun? (viewed 172149 times)
  37. Why is a day divided into 24 hours? (viewed 168795 times)
  38. How does the position of Moonrise and Moonset change? (viewed 164532 times)
  39. Who named the planets and who decides what to name them? (viewed 157398 times)
  40. Why are the Moon and Sun sometimes orange or red? (viewed 155664 times)
  41. When was the last time all 9 planets were aligned? (viewed 153804 times)
  42. Why do airplanes take longer to fly West than East? (viewed 152204 times)
  43. Is Pluto a planet? (viewed 150102 times)
  44. Is the distance from the Earth to the Sun changing? (viewed 149339 times)
  45. What is at the end of the Universe? (viewed 145888 times)
  46. How can I find the star I have "bought"? (viewed 142558 times)
  47. How much money is spent on space exploration? (viewed 141249 times)
  48. Why are there both high and low tides? (viewed 130570 times)
  49. How do astronauts take baths and use restrooms in space? (viewed 129988 times)
  50. What is a nova? (viewed 128951 times)
  51. Can we feel the Earth spin? (viewed 128928 times)
  52. What direction do planets rotate? (viewed 128919 times)
  53. Is the Sun expanding? Will it ever explode? (viewed 127446 times)
  54. What is the largest galaxy? (viewed 127063 times)
  55. How many known galaxies are there? (viewed 125848 times)
  56. Does your weight change between the poles and the equator? (viewed 125041 times)
  57. Do stars move in the sky? (viewed 122175 times)
  58. What are the advantages and disadvantages of using a telescope in space? (viewed 117230 times)
  59. Can I buy a star? (viewed 116962 times)
  60. Why do all the planets orbit in the same plane? (viewed 115106 times)
  61. Will the sun go supernova in six years and destroy Earth (as seen on Yahoo)? (viewed 114345 times)
  62. How are light and heavy elements formed? (viewed 112681 times)
  63. Are there telescopes that can see the flag and lunar rover on the Moon? (viewed 112127 times)
  64. What is the hottest time of day? (viewed 111272 times)
  65. Does the Sun have a scientific name? (viewed 110948 times)
  66. Why hasn't NASA gone back to the moon? (viewed 110737 times)
  67. How do stars move in the Galaxy? (viewed 110343 times)
  68. What happens when galaxies collide? (viewed 109967 times)
  69. Who first measured the speed of light? (viewed 109526 times)
  70. Why do planets have elliptical orbits? (viewed 108959 times)
  71. How do rockets work? (viewed 108495 times)
  72. What is the size of the Solar System? (viewed 107615 times)
  73. What is the physical difference between a star and a planet? (viewed 107388 times)
  74. Will the magnetic field of the Earth reverse its direction in the future? Will this cause problems? (viewed 106843 times)
  75. What would happen if an impact caused Earth to stop rotating? (viewed 106693 times)
  76. What was there before the Big Bang and what is there outside of our universe? (viewed 106461 times)
  77. How much money do astronomers make? (viewed 106328 times)
  78. When is the next comet due to arrive? (viewed 106119 times)
  79. What will happen to life on Earth when the Sun becomes a red giant? (viewed 104372 times)
  80. How long does a solar eclipse last? (viewed 104342 times)
  81. Does evolution contradict the second law of thermodynamics? (viewed 104311 times)
  82. Do black holes die? If so how? (viewed 103982 times)
  83. What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (viewed 103833 times)
  84. How do you calculate the lifetime of the Sun? (viewed 103373 times)
  85. How many constellations are there? (viewed 102908 times)
  86. What elements make up the Sun? (viewed 102822 times)
  87. What is the observational difference between a star and a planet? (viewed 101067 times)
  88. Does the Sun rotate? (viewed 100319 times)
  89. What's the difference between astronomy and astrology? (viewed 99987 times)
  90. What do astronauts do all day in the International Space Station? (viewed 99438 times)
  91. Does the Sun move around the Milky Way? (viewed 99219 times)
  92. What is apparent magnitude? (viewed 95545 times)
  93. Does gravity vary across the surface of the Earth? (viewed 95244 times)
  94. What would happen if the gravity on Earth was suddenly turned off? (viewed 94635 times)
  95. Which planet is most similar to Earth? (viewed 94283 times)
  96. How many meteorites hit Earth each year? (viewed 94134 times)
  97. What are constellations used for? (viewed 92163 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 91248 times)
  99. Why do different stars appear with seasons? (viewed 90708 times)
  100. How do astronomers use math in their jobs? (viewed 90575 times)
  101. How critical is the Earth-Sun distance in maintaining our average temperatures on Earth? (viewed 90329 times)
  102. What kind of schooling is necessary to become an astronomer? (viewed 89853 times)
  103. Is there a proof that Earth moves? (viewed 89152 times)
  104. Why are stars and planets round? (viewed 89136 times)
  105. Where did the Universe come from? (viewed 88996 times)
  106. Does the Sun orbit the Earth as well as the Earth orbiting the Sun? (viewed 88285 times)
  107. Why is the Moon so bright? (viewed 88272 times)
  108. Why is the Universe flat and not spherical? (viewed 88197 times)
  109. What makes the wind? (viewed 87617 times)
  110. Have astronomers discovered Earth's second moon? (viewed 87498 times)
  111. What would happen if an asteroid 10 kilometers across hit the Earth? (viewed 86753 times)
  112. What is a singularity? (viewed 86266 times)
  113. How can a star burn with no oxygen? (viewed 85636 times)
  114. What is the difference between a "star" and a "sun"? (viewed 83933 times)
  115. Where does the name "Milky Way" come from? (viewed 82416 times)
  116. Why does the Earth tilt back and forward once a year? (viewed 82320 times)
  117. What are RA and DEC? (viewed 82159 times)
  118. What would happen if Earth had more than one moon? (viewed 80899 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 80586 times)
  120. Since Earth is spinning, why do we land in the same place when we jump or fall? (viewed 79288 times)
  121. What are the requirements for being a planet? (viewed 79043 times)
  122. How many stars are born and die each day? (viewed 78065 times)
  123. What kind of rock is the moon made of? (viewed 77964 times)
  124. Why aren't there any green stars? (viewed 77533 times)
  125. Did astronauts really go to the Moon, or is it a hoax? (viewed 77105 times)
  126. How are galaxies formed? (viewed 76736 times)
  127. Will the Sun become a black hole one day? (viewed 74753 times)
  128. How are black holes made? Could one be made close to us? (viewed 74589 times)
  129. What is the density of a black hole? (viewed 74165 times)
  130. What would happen if a supermassive black hole came close to the Earth? (viewed 74006 times)
  131. Why is the moon in a different place every night? (viewed 73594 times)
  132. Who has landed on the moon? (viewed 73361 times)
  133. What would you see from inside a black hole? (viewed 71862 times)
  134. Do most astronomers believe in God based on the available scientific evidence? (viewed 71552 times)
  135. Can moons have moons? (viewed 71435 times)
  136. How do we weigh objects in space? (viewed 70995 times)
  137. What happens to a substance if its speed is more than the speed of light? (viewed 70977 times)
  138. Why can't you see stars during the day? (viewed 70965 times)
  139. How do rockets move in space? (viewed 70697 times)
  140. How often does the Sun pass through a spiral arm in the Milky Way? (viewed 70465 times)
  141. Can you fire a gun on the Moon? (viewed 70443 times)
  142. How do astronomers measure the brightness of stars? (viewed 70179 times)
  143. How can the Universe expand faster than the speed of light during inflation? (viewed 70102 times)
  144. Does the Mediterranean sea have tides? (viewed 69981 times)
  145. What would happen if you took off your helmet in space? (viewed 69905 times)
  146. What are some of the effects of solar flares on Earth? (viewed 69772 times)
  147. When the Sun converts mass to energy, do the orbits of the planets change? (viewed 69251 times)
  148. How is astronomy impacted by trigonometry? (viewed 68737 times)
  149. How do we know the mass of the Earth and the Moon? (viewed 68683 times)
  150. Is it possible to measure the temperature of the Sun? (viewed 68466 times)
  151. How does the Sun compare to other stars? (viewed 67398 times)
  152. Why do stars change colour when they twinkle? (viewed 67301 times)
  153. How do you measure a planet's mass? (viewed 67177 times)
  154. How does the Moon stay "suspended" in the air? (viewed 66862 times)
  155. What are the "dog days of summer"? (viewed 66711 times)
  156. What is the evidence supporting the nebula theory of Solar System formation? (viewed 66553 times)
  157. How are elements heavier than iron formed? (viewed 66332 times)
  158. Why do we not have eclipses every month? (viewed 66246 times)
  159. What kinds of jobs do astronomers do? (viewed 65573 times)
  160. Does quantum entanglement imply faster than light communication? (viewed 65080 times)
  161. If the universe is infinite does that mean there is an infinite number of "me"s? (viewed 64179 times)
  162. What are black holes made of? (viewed 63726 times)
  163. What causes seasons? (viewed 63315 times)
  164. How did the stars get named? (viewed 63167 times)
  165. Why doesn't the earliest sunset occur on the shortest day of the year? (viewed 62949 times)
  166. Where does the name "Moon" come from? (viewed 62823 times)
  167. When can I see the Moon through the hole in the Pantheon? (viewed 62751 times)
  168. How long would it take the Earth to fall into the Sun? (viewed 62546 times)
  169. Where did the matter in the universe come from? (viewed 62401 times)
  170. How did asteroids form and what is the difference between an asteroid and a comet? (viewed 62398 times)
  171. How fast is the Universe expanding? (viewed 62352 times)
  172. How do you measure the mass of a star? (viewed 62221 times)
  173. Traveling at light speed, how long would it take to get to the nearest galaxy? (viewed 62131 times)
  174. What are Altitude and Azimuth? (viewed 62081 times)
  175. How does light pollution affect astronomers? (viewed 61973 times)
  176. Are there stars outside of galaxies? (viewed 61791 times)
  177. What's the best college for astronomy? (viewed 61676 times)
  178. Why do planets not twinkle? (viewed 61593 times)
  179. Where, in relation to the entire universe, is the Milky Way located? (viewed 61074 times)
  180. Why doesn't the length of each day change much around the solstices? (viewed 61032 times)
  181. What would happen to us if the sun went out for an hour? (viewed 60901 times)
  182. What is the mass of the Universe? (viewed 60146 times)
  183. What's the difference between dark matter and dark energy? (viewed 59608 times)
  184. How can I calculate the position or path of the Sun for a given time and location? (viewed 58776 times)
  185. Does the Moon rotate? (viewed 58648 times)
  186. Could there be life in the galaxies nearest to the Milky Way? (viewed 58508 times)
  187. Why does the Sun's apparent path through the sky change throughout the year? (viewed 58415 times)
  188. Why does the Earth have only one moon? (viewed 58183 times)
  189. Can any galaxies be seen with the naked eye? (viewed 57835 times)
  190. How does astronomy benefit humankind? (viewed 57784 times)
  191. How does the parachute in a model rocket work? (viewed 57463 times)
  192. What is the origin of spiral structure in galaxies? (viewed 57392 times)
  193. How close was the Moon to the Earth when it formed? (viewed 57178 times)
  194. How long does the supernova stage of a star last? (viewed 56709 times)
  195. What makes up most of the Universe? (viewed 56455 times)
  196. What is the shape of the universe? (viewed 56328 times)
  197. Why is looking out into space the same as looking back in time? (viewed 56229 times)
  198. What is the largest structure in the universe? (viewed 55678 times)
  199. What can we learn from the color of a star? (viewed 55648 times)
  200. Why isn't the summer solstice the hottest day of the year? (viewed 55405 times)
  201. Where are stars born? (viewed 55069 times)
  202. How do astronauts use math in their jobs? (viewed 55032 times)
  203. What is a star's "spectrum"? (viewed 54845 times)
  204. What is the size of a black hole? (viewed 54711 times)
  205. Are names given to black holes? (viewed 54520 times)
  206. If gravity is a "curvature of space" rather than a force, why do a ball and bullet follow different paths? (viewed 54167 times)
  207. Can you see satellites? (viewed 54104 times)
  208. Which constellation does our Sun belong to? (viewed 54039 times)
  209. How do we measure the size of the Moon and of the Sun? (viewed 53832 times)
  210. How do you calculate the azimuth and altitude of an object? (viewed 53783 times)
  211. How do the astronauts communicate in space if sound cannot travel in a vacuum? (viewed 53555 times)
  212. What happens to a bullet fired on the moon? (viewed 53306 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 53074 times)
  214. How can I find the distance to the Sun on any given day? (viewed 52895 times)
  215. What other careers involve Astronomy besides Astronomer? (viewed 52738 times)
  216. Are aliens or UFOs real? (viewed 52706 times)
  217. Why do we see stars? (viewed 52663 times)
  218. How can I measure the distance of a star? (viewed 52349 times)
  219. Which hemisphere has the best view of the Milky Way? (viewed 51958 times)
  220. Is the speed of light constant? (viewed 51770 times)
  221. What are some astronomy science fair projects? (viewed 51549 times)
  222. Are there any asteroids on a collision course with Earth? (viewed 51397 times)
  223. How long has there been water on Earth? (viewed 51145 times)
  224. Why is the sky blue and not blue & purple? (viewed 50986 times)
  225. Why is twilight short near the equator? (viewed 50762 times)
  226. Are meteorites hot or cold when they hit Earth? (viewed 50656 times)
  227. What would happen if the Moon fell out of its orbit around Earth? (viewed 50622 times)
  228. Where did all the water in the universe come from? (viewed 50616 times)
  229. Is time travel possible? (viewed 50459 times)
  230. Would your weight change as you go underground? (viewed 50419 times)
  231. Who discovered each planet? (viewed 50230 times)
  232. Why does the Moon look big on the horizon? (viewed 50107 times)
  233. Can we look back far enough in time to see the Big Bang? (viewed 50101 times)
  234. What do a galaxy's colors mean? Are they its true colors? (viewed 50054 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 49809 times)
  236. Why is it difficult to understand the expansion of the universe? (viewed 49365 times)
  237. What skills do astronomers need? (viewed 48919 times)
  238. What is the difference between nutation and precession of the Earth? (viewed 48877 times)
  239. How is the time of sunrise calculated? (viewed 48765 times)
  240. What is a graviton? (viewed 48718 times)
  241. Are the planes of solar systems aligned with the plane of the Galaxy? (viewed 48603 times)
  242. What's the difference between astronomy and astrophysics? (viewed 48504 times)
  243. If light has no mass, then what draws it into a black hole? (viewed 48346 times)
  244. How do we know what other planets (and stars, galaxies, etc.) are made of? (viewed 47684 times)
  245. What do I need to do to become an astronomer? (viewed 46768 times)
  246. Why do the size and brightness of the full moon change? (viewed 46443 times)
  247. Do dead stars still shine? (viewed 46399 times)
  248. Do supermassive black holes cause galaxy rotation? (viewed 46327 times)
  249. How do gravitons escape black holes to tell the universe about their gravity? (viewed 46310 times)
  250. What is a wormhole? (viewed 46178 times)
  251. How are black holes discovered? (viewed 45856 times)
  252. Why does the Sun appear larger on the horizon than overhead? (viewed 45621 times)
  253. Can we find the place where the Big Bang happened? (viewed 45362 times)
  254. Where is the nearest black hole? (viewed 45359 times)
  255. The Moon slows the Earth's rotation, but how fast was it spinning billions of years ago? (viewed 45279 times)
  256. Will we get sucked into the black hole at the center of the Milky Way? (viewed 45263 times)
  257. Why are most months 30 or 31 days long? (viewed 45222 times)
  258. Why can't we see Venus at night when it is an inner planet? (viewed 44989 times)
  259. Is the Earth slowly getting larger? (viewed 44915 times)
  260. Why are there stars? (viewed 44898 times)
  261. How do galaxies collide in an expanding universe? (viewed 44867 times)
  262. Can I calculate the size of the Universe by converting light years to kilometres? (viewed 44688 times)
  263. Why does Barnard 68 appear dark? (viewed 44211 times)
  264. Why don't people walk upside-down on the bottom of the Earth? (viewed 43429 times)
  265. Are Kuiper Belt Objects asteroids? Are large Kuiper Belt Objects planets? (viewed 43393 times)
  266. Can the acceleration of the Universe be analogous to apparent acceleration in a airplane? (viewed 42997 times)
  267. Did life originate on Earth, or did it come from somewhere else? (viewed 42757 times)
  268. What is the best way to see the Milky Way? (viewed 42711 times)
  269. Are there eclipses on other planets? (viewed 42653 times)
  270. Could the Universe have expanded faster than the speed of light at the Big Bang? (viewed 42625 times)
  271. Is there a "South Star"? (viewed 42457 times)
  272. Was the Sun made in a supernova? (viewed 42447 times)
  273. How does Astronomy involve Chemistry? (viewed 42408 times)
  274. What is the biggest crater recorded on Earth? (viewed 42388 times)
  275. Why does the location of sunrise change? (viewed 42370 times)
  276. Has there been an experiment that measured speed faster than the speed of light in vacuum? (viewed 42325 times)
  277. How long could life on Earth survive if the Sun stopped shining? (viewed 42210 times)
  278. What is the difference between the "Doppler" redshift and the "gravitational" or "cosmological" redshift? (viewed 42153 times)
  279. How much longer will the Earth last? (viewed 42001 times)
  280. Why doesn't dark matter fall into a black hole? (viewed 41982 times)
  281. How would the weather on Earth be different if it were a cube? (viewed 41980 times)
  282. How much can the location of sunset differ from due West? (viewed 41754 times)
  283. What happens to spacetime inside a black hole? (viewed 41604 times)
  284. Can I buy land on the Moon? (viewed 41453 times)
  285. Is the Moon hollow? (viewed 41194 times)
  286. Why does the Earth only see one side of the Moon? (viewed 41187 times)
  287. What happens when two black holes get too close? (viewed 41120 times)
  288. What's the biggest meteorite? (viewed 40795 times)
  289. What are the names of the three stars in Orion's belt? (viewed 40740 times)
  290. What is time dilation? (viewed 40659 times)
  291. What color would Mars be if you were standing on it? (viewed 40623 times)
  292. What is the most distant known galaxy? (viewed 40437 times)
  293. What if the Earth rotated twice as fast? (viewed 40186 times)
  294. How can two moons of Saturn share the same orbit? (viewed 40170 times)
  295. Could someone travel the universe in his or her own lifetime? (viewed 39848 times)
  296. Can terrestrial planets have rings? (viewed 39693 times)
  297. Why do people draw stars with five points? (viewed 39671 times)
  298. How long would it take for a mini-black hole to eat the Earth? (viewed 39525 times)
  299. How do we feel heat? (viewed 39397 times)
  300. How many Astronauts have been in space? (viewed 39359 times)
  301. Is it possible to see the full Moon and the Sun simultaneously in high northern latitudes when the Sun doesn't set? (viewed 39352 times)
  302. What are "blue stragglers" in globular clusters? (viewed 39275 times)
  303. Why do pictures of distant galaxies have higher resolution than those of nearby planets? (viewed 38946 times)
  304. Why can we see the sun's image before sunrise and after sunset? (viewed 38923 times)
  305. What is the typical size of a visible shooting star? (viewed 38727 times)
  306. If a white dwarf is a "dead" star, why is it so hot? (viewed 38615 times)
  307. How do we know that nuclear fusion is still going on in the Sun? (viewed 38554 times)
  308. How fast does the Earth go at perihelion and aphelion? (viewed 38471 times)
  309. Does Mt. Everest cast a shadow on the moon? (viewed 38395 times)
  310. Is the Great Wall the largest galaxy cluster? (viewed 38393 times)
  311. How does night and day work? (viewed 38224 times)
  312. Does the Sun have an iron surface? (viewed 38215 times)
  313. Why are Saturn's rings flat? (viewed 38151 times)
  314. Do you think it's possible to maintain life on other planets? (viewed 38110 times)
  315. What is a dimension? (viewed 38076 times)
  316. Is the Sun always up for exactly 12 hours at the equator? (viewed 38061 times)
  317. Can a person go into a black hole and come out alive? (viewed 37978 times)
  318. Can you see the future as you fall into a black hole? (viewed 37978 times)
  319. On which days can I see the Moon in the evening / morning and why is this so? (viewed 37842 times)
  320. Can I communicate faster than light? (viewed 37756 times)
  321. Where do planetary rings come from, and what are they made of? (viewed 37706 times)
  322. What is the speed of gravity? (viewed 37697 times)
  323. Why do clocks turn in the opposite direction from the Earth and Moon? (viewed 37668 times)
  324. Who (and when) discovered that the earth's axis is on a 23 degree tilt? (viewed 37635 times)
  325. What is Earthrise over the Moon? (viewed 37483 times)
  326. What can I use for fuel in my homemade rocket? (viewed 37356 times)
  327. How big is the universe? (viewed 37311 times)
  328. Where is the supernova remnant that led to our solar system? (viewed 37311 times)
  329. What is the approximate GPA needed in High School in Math and Science to be an astronomer? (viewed 37259 times)
  330. Are all stars the same? (viewed 37252 times)
  331. What companies or businesses can astronomers work for? (viewed 37164 times)
  332. How do we determine the age of the universe? (viewed 37079 times)
  333. Is there really a 10th planet? (viewed 36929 times)
  334. Why is sea water salty, and not lake water? (viewed 36795 times)
  335. Does the Coriolis force determine which way my toilet drains? Does it affect black holes? (viewed 36483 times)
  336. Is there a beginning and an end to a galaxy's life? (viewed 36473 times)
  337. What would happen to the Earth if an asteroid hit the Moon? (viewed 36430 times)
  338. If the universe is 15 billion years old, how can it be larger than 15 billion light years across? (viewed 36390 times)
  339. How many stars can I see? (viewed 36372 times)
  340. How do I tell which planet is which? (viewed 36262 times)
  341. How can the universe be "flat"? We're 3D! (viewed 36256 times)
  342. How do we know the Milky Way is a spiral galaxy? (viewed 36095 times)
  343. How do we define distance in an expanding universe? (viewed 35971 times)
  344. How are photons created and destroyed? (viewed 35966 times)
  345. Do the Sun's or Earth's magnetic field reverse? (viewed 35821 times)
  346. How can I find my age on another planet? (viewed 35430 times)
  347. Why are there blue shifted galaxies? (viewed 35314 times)
  348. Is Andromeda part of the Milky Way? Where can I find them in the sky? (viewed 35161 times)
  349. Why have star signs shifted by one constellation? (viewed 35058 times)
  350. Why do humans want to go in space? (viewed 34841 times)
  351. How does the brightness of a star depend on its distance from us? (viewed 34770 times)
  352. Can a lunar and a solar eclipse happen in the same month? When will this happen next? (viewed 34667 times)
  353. What is the pattern to the distances between each planet and the sun? (viewed 34661 times)
  354. How are planets detected around other stars? (viewed 34598 times)
  355. What was that really big falling star that I saw? (viewed 34577 times)
  356. What kind of eyepieces do I need to look at planets? (viewed 34532 times)
  357. Who came up with the name "black hole"? (viewed 34446 times)
  358. What is the significance of the second focus of elliptical orbits of planets in our Solar System? (viewed 34441 times)
  359. What would happen if two stars collided? (viewed 34441 times)
  360. Will we ever stop having solar eclipses because of the moon's motion away from the Earth? (viewed 34392 times)
  361. How can we estimate the number of Earth-like planets in the Galaxy? (viewed 34312 times)
  362. How do astronauts communicate with their families from space? (viewed 34296 times)
  363. Is the Earth at the centre of the Universe? (viewed 34182 times)
  364. Is there a simple formula to calculate solar eclipse timings from any position on Earth? (viewed 34143 times)
  365. When we look back to the Big Bang, why don't we see the universe as a tiny speck of matter? (viewed 34122 times)
  366. Why don't astronomers use everyday units to measure distances (what is an AU or a pc)? (viewed 33918 times)
  367. How is it that we see farther out in space (farther back in time) than in the past? (viewed 33836 times)
  368. Will the Moon be invisible in 500 million years? (viewed 33677 times)
  369. How do I become both an astronaut and an astronomer? (viewed 33426 times)
  370. Why can't a plane fly slowly and let the Earth pass underneath? (viewed 33416 times)
  371. Are Earth and the Moon "twin planets"? (viewed 33381 times)
  372. How dangerous are the asteroids? (viewed 33326 times)
  373. Which American colleges teach astronomy? (viewed 33290 times)
  374. Why is our solar system so different from all the others we've found? (viewed 33238 times)
  375. How hot is each one of the layers of the sun? (viewed 33187 times)
  376. Why is Uranus tipped on its side? (viewed 33124 times)
  377. Can you describe a day on the job as an astronomer? (viewed 32960 times)
  378. Can we colonize other planets? (viewed 32950 times)
  379. How do sunrise and sunset times change with altitude? (viewed 32744 times)
  380. Is the Local Group expanding along with the entire Universe? (viewed 32474 times)
  381. Why do constellations look the same after several years even though all the stars are moving? (viewed 32365 times)
  382. What are quasars made of? (viewed 32268 times)
  383. How can I calculate distances between stars? (viewed 32226 times)
  384. Is it true that the Sun burns off a billion tons of gas every 5 seconds? (viewed 32187 times)
  385. Why do astronauts in space need to exercise? (viewed 32146 times)
  386. Is the universe really like an expanding balloon? (viewed 32143 times)
  387. Why are there no craters on Earth? Did all the meteorites miss us? (viewed 32097 times)
  388. Why doesn't gravity change the speed of light? (viewed 31983 times)
  389. Is the gravitational force exerted by the Earth on the Moon equal to the centripetal force acting on the Moon? (viewed 31792 times)
  390. What is dark matter? (viewed 31761 times)
  391. Is it possible to count the stars? (viewed 31696 times)
  392. Can superheavy elements (such as Z=116 or 118) be formed in a supernova? Can we observe them? (viewed 31630 times)
  393. Is time travel possible using merging black holes? (viewed 31570 times)
  394. What is happening just around the black hole in the center of the Milky Way? (viewed 31458 times)
  395. Did the speed of light change over the history of the universe? (viewed 31333 times)
  396. Can we see dead stars with the naked eye? (viewed 31309 times)
  397. How big a change in the Earth's orbit would be required to destroy all life? (viewed 31290 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 31195 times)
  399. How do we measure distances to other stars? (viewed 31186 times)
  400. How do I make a scale model of the Solar System? (viewed 31036 times)
  401. What happens when an antimatter black hole collides with a matter blackhole? (viewed 30987 times)
  402. Are time machines possible? (viewed 30872 times)
  403. How many moles of stars are in the known universe? (viewed 30572 times)
  404. How are galaxy distances inferred from their recessional velocities? (viewed 30353 times)
  405. Why is the time between two successive full moons different from the lunar synodic month? (viewed 30317 times)
  406. How can we tell what the interiors of planets are like? (viewed 30260 times)
  407. What happens when you change the mass of a White Dwarf or Neutron Star? (viewed 30208 times)
  408. What do "homogeneity" and "isotropy" mean? (viewed 30046 times)
  409. Is there any limitation to what a black hole can "suck" in? (viewed 30037 times)
  410. Does the Milky Way spin counter-clockwise? If so, do all spiral galaxies spin in this direction and why? (viewed 30036 times)
  411. What is the farthest in space that we have gone? (viewed 29987 times)
  412. What would happen if a human were exposed to space without wearing a spacesuit? (viewed 29962 times)
  413. Will the seasons change due to precession? (viewed 29754 times)
  414. How can we know that there are other galaxies if we cannot leave ours? (viewed 29737 times)
  415. Can astronauts produce water in space? (viewed 29699 times)
  416. What are the closest and/or brightest stars? (viewed 29679 times)
  417. What's that dark spot on the Sun? (viewed 29618 times)
  418. How was the starting point for the Julian Date system chosen? (viewed 29617 times)
  419. How can I tell if the rock I found is a meteorite? (viewed 29601 times)
  420. Aren't jobs in astronomy scarce? (viewed 29581 times)
  421. Do we see the same stars from above and below the equator? (viewed 29576 times)
  422. How do we know if the universe will keep expanding forever? (viewed 29393 times)
  423. Do astronomers believe in astrology? (viewed 29343 times)
  424. Why does the SETI project search for radio signals? (viewed 29303 times)
  425. Did I see the Aurora Borealis as a child? (viewed 29302 times)
  426. How long does it take the Big Dipper to move in the sky? (viewed 29277 times)
  427. What are the facts about the Star of Bethlehem? (viewed 29140 times)
  428. Don't tachyons travel faster than light? (viewed 29100 times)
  429. Why do most moons orbit their planets at the equator? (viewed 29092 times)
  430. Why do we study black holes? (viewed 29082 times)
  431. When are there 5 Sundays in February? (viewed 29064 times)
  432. Could an astronaut or satellite fall into a black hole that we didn't know about? (viewed 29019 times)
  433. What are the atmospheres of Mars and Pluto like? (viewed 28973 times)
  434. Wouldn't the Big Bang theory be considered a hypothesis and not a theory? (viewed 28941 times)
  435. Do you believe in UFOs? (viewed 28762 times)
  436. Can you use an infinite line of reflectors to send light to the edge of the Universe? (viewed 28690 times)
  437. What does the term "visible universe" mean? (viewed 28631 times)
  438. Could you tell me about the life cycle of galaxies? (viewed 28555 times)
  439. Has anyone made a map of the Milky Way? (viewed 28543 times)
  440. Was I hit by a meteorite? (viewed 28540 times)
  441. What colors are visible through an amateur telescope? (viewed 28517 times)
  442. How are galaxies named? (viewed 28480 times)
  443. How can geometry be different in space? (viewed 28415 times)
  444. Why are the compositions of comets and asteroids different? (viewed 28132 times)
  445. Why do so many of the world's UFO sightings happen in America? (viewed 28001 times)
  446. What's the best thing about being an astronomer? (viewed 27991 times)
  447. How do asteroids, meteors and comets disappear? (viewed 27849 times)
  448. Can two lunar eclipses occur in the same month? (viewed 27743 times)
  449. How much time do astronomers spend looking through telescopes? (viewed 27734 times)
  450. How do astronomers measure the radius of a star? (viewed 27675 times)
  451. Will winter and summer constellations change due to abnormal warmth or cold on Earth? (viewed 27651 times)
  452. How can we see galaxies if their stars are so faint? (viewed 27508 times)
  453. How will the two black holes that are going to collide affect Earth? (viewed 27484 times)
  454. Have there been other Big Bangs before? (viewed 27461 times)
  455. How do I explain to my children why the Moon has phases? (viewed 27406 times)
  456. What is the origin of the stellar classification system "OBAFGKM"? (viewed 27334 times)
  457. How are galaxies and solar systems similar? (viewed 27272 times)
  458. Can life exist on the recently discovered extrasolar planets? (viewed 27215 times)
  459. How close do you have to come to the Earth to be influenced by its gravity? (viewed 27174 times)
  460. Is there a project I can do on black holes? (viewed 27115 times)
  461. Is the Milky Way a collision of two galaxies? (viewed 27090 times)
  462. Does the Moon look different in the northern and southern hemispheres? (viewed 27034 times)
  463. Do the magnitudes and colors of stars ever change? (viewed 27001 times)
  464. How can we measure distances to more stars? (viewed 26988 times)
  465. Could you escape from a black hole if you were able to go faster than the speed of light? (viewed 26935 times)
  466. How do scientists slow light down? (viewed 26891 times)
  467. Do asteroids hit the sun? (viewed 26724 times)
  468. Is infinite temperature possible? (viewed 26700 times)
  469. How close does a supernova need to be to damage the Earth's environment? (viewed 26684 times)
  470. Do we know everything about the Sun? (viewed 26659 times)
  471. Can "tired light theory" explain the observed redshifts of galaxies? (viewed 26609 times)
  472. What supernova created the Crab nebula? (viewed 26596 times)
  473. Is it worthwhile to continue the search for extraterrestrial life? (viewed 26571 times)
  474. Can one star orbit another? (viewed 26477 times)
  475. Can double stars have planets? (viewed 26477 times)
  476. What causes gamma ray bursts? (viewed 26406 times)
  477. How far does a galaxy extend? (viewed 26342 times)
  478. How do I polar align my telescope? (viewed 26163 times)
  479. What will happen to the Milky Way in the future? (viewed 26141 times)
  480. Can astronauts play musical instruments in space? (viewed 26116 times)
  481. Is there such a thing as hyperspace? (viewed 26048 times)
  482. What type of energy does a black hole have? (viewed 26037 times)
  483. Which part of the sky did the famous 'wow' signal originate from? (viewed 26035 times)
  484. Which way does the sun travel in the southern hemisphere? (viewed 26035 times)
  485. What is sidereal time? (viewed 26026 times)
  486. Is there oxygen in the atmospheres of other planets? (viewed 26026 times)
  487. What is the farthest Northern Latitude in which the Magellanic Clouds can be seen? (viewed 26002 times)
  488. What happens to the material that has been sucked into a black hole? (viewed 25979 times)
  489. Can a human give birth in space? (viewed 25973 times)
  490. Why do the explosions of Type Ia supernovae have a more predictable spectrum than those of regular Type II supernovae? (viewed 25897 times)
  491. What is a Cepheid variable? (viewed 25874 times)
  492. What is "nothing", from a scientific point of view? (viewed 25853 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 25810 times)
  494. What's the object I saw that moved across the sky and then got very bright? (viewed 25783 times)
  495. Is there sound coming from the Sun? (viewed 25768 times)
  496. How will a change in the speed of light affect the evolution of the Universe? (viewed 25757 times)
  497. How different would the night sky have looked in 40,000 B.C.? (viewed 25739 times)
  498. When did people discover that the Sun is a star? (viewed 25547 times)
  499. Why do we assume that the universe is homogeneous? (viewed 25516 times)
  500. How do we know what parameters to use when simulating the collision of the Milky Way and Andromeda? (viewed 25503 times)
  501. Why is the shadow on the Moon the shape it is? (viewed 25480 times)
  502. How do we know that sunspots are associated with the Sun's magnetic field? (viewed 25420 times)
  503. If we invented special suits could we ever go to the sun? (viewed 25385 times)
  504. Are planetary nebulae the result of supernovae? (viewed 25384 times)
  505. When unmanned spacecraft accelerate in space, what causes them to slow down? (viewed 25366 times)
  506. Are there any dark stars or dark galaxies made of dark matter? (viewed 25291 times)
  507. What calculations go into predicting eclipses? (viewed 25254 times)
  508. What is the difference between homogeneity and isotropy? (viewed 25238 times)
  509. Was Stonehenge built to mark solar phenomena? (viewed 25192 times)
  510. What is our galaxy's halo made of, and how was it formed? (viewed 25190 times)
  511. Is there a list of the sizes of different kinds of stars? (viewed 25124 times)
  512. Can I see a quasar? (viewed 25096 times)
  513. What process would bring about a quark star? (viewed 25086 times)
  514. How many sunspots can the Sun have at once? (viewed 25016 times)
  515. What's so exciting about the new planet around 55 Cancri? (viewed 24986 times)
  516. How are asteroid compositions and classifications determined? (viewed 24970 times)
  517. Did a giant impact cause the Dark Ages? (viewed 24964 times)
  518. What is a Dyson Sphere? (viewed 24919 times)
  519. Can I see details on Venus? (viewed 24911 times)
  520. Have gravitational waves been proven to exist? (viewed 24904 times)
  521. Can any comparison be made between spiral galaxies and hurricanes? (viewed 24904 times)
  522. Why are there more maria on the near side of the Moon? (viewed 24749 times)
  523. What equipment do I need for astrophotography? (viewed 24692 times)
  524. What happened to all the black holes that were around in the early universe? (viewed 24674 times)
  525. What happened to the girl who named Pluto? (viewed 24666 times)
  526. How is it proved that the Universe is expanding? (viewed 24619 times)
  527. Why are there active volcanos on Io? (viewed 24612 times)
  528. Would the biggest airplanes cause tsunamis if they crashed? (viewed 24591 times)
  529. Does Cerenkov radiation travel faster than light? (viewed 24590 times)
  530. Why are telescopes kept in cold conditions? (viewed 24560 times)
  531. Is there any possibility that the Solar System or the Universe is in a black hole? (viewed 24498 times)
  532. If clocks run slow in a gravitational field, how can we know the true age of the Solar System and Universe? (viewed 24323 times)
  533. How big is the Hubble Ultra Deep Field image? (viewed 24298 times)
  534. How big was the Sun when it first "fired up"? (viewed 24285 times)
  535. How can we compare dark matter and dark energy? (viewed 24279 times)
  536. If the Universe was infinitely dense at the Big Bang, why didn't time stand still? (viewed 24239 times)
  537. How long do supernova remnants last? (viewed 24175 times)
  538. What caused Shoemaker-Levy 9 to split up? (viewed 24151 times)
  539. Why do photos of space taken from space never show any stars? (viewed 24137 times)
  540. Could we send a space mission to a comet? (viewed 24123 times)
  541. How do solar flares affect airline pilots? (viewed 24083 times)
  542. Why doesn't light from distant galaxies reach us instantaneously? (viewed 24032 times)
  543. Could we be seeing dead stars? (viewed 23956 times)
  544. How are sunspots formed? (viewed 23956 times)
  545. Can you give me advice on buying a telescope? (viewed 23951 times)
  546. How does the Earth compare in size to the entire universe at the present epoch? (viewed 23851 times)
  547. Could a different theory of gravity explain the dark matter mystery? (viewed 23836 times)
  548. As the universe expands, why don't galaxies get stretched out? (viewed 23768 times)
  549. Where does the kinetic energy of infalling bodies come from? (viewed 23752 times)
  550. Why doesn't NASA build rotating spacecraft to simulate gravity? (viewed 23752 times)
  551. Can I build an instrument to measure the size of the Sun and of the Moon? (viewed 23729 times)
  552. How many comets are currently orbiting our sun? (viewed 23699 times)
  553. Can you tell time by the Big Dipper? (viewed 23633 times)
  554. Why is the Hubble Space Telescope in space? (viewed 23626 times)
  555. Did I really hear a meteor? (viewed 23524 times)
  556. How do we know that superclusters are the largest structures in the universe? (viewed 23510 times)
  557. Why is it important to study meteorites? (viewed 23505 times)
  558. How powerful are quasars? (viewed 23459 times)
  559. Would extraterrestrial civilizations know that there is life on Earth? (viewed 23452 times)
  560. Why are telescopes located in remote places? (viewed 23409 times)
  561. How can I contribute to science as an amateur astronomer? (viewed 23384 times)
  562. How is the Cepheid yardstick validated? (viewed 23347 times)
  563. Are the asteroids the remains of a planet which broke apart? (viewed 23318 times)
  564. Do unmanned spacecraft like Voyager travel in straight lines? (viewed 23262 times)
  565. Did time go slower just after the Big Bang? (viewed 23216 times)
  566. Do the Earth's magnetic poles ever change places? (viewed 23186 times)
  567. Are there any new craters on the moon? (viewed 23173 times)
  568. Can supernovae hinder the formation of life in galaxies? (viewed 23170 times)
  569. What would happen if there was a collision between two white dwarfs? (viewed 23169 times)
  570. Do galaxies orbit around anything? (viewed 23158 times)
  571. Why are stars of different masses? (viewed 23151 times)
  572. How do unmanned space probes avoid running into things? (viewed 23141 times)
  573. Do similar laws of physics throughout the Universe imply that all life must be like life on Earth? (viewed 23064 times)
  574. How do planets capture satellites? (viewed 23057 times)
  575. How do I become an astronomical artist? (viewed 23048 times)
  576. What kind of instruments are used to detect extrasolar planets? (viewed 23046 times)
  577. How could galaxies have gotten so far away in only 15 billion years? (viewed 23020 times)
  578. Why can't relative velocities add up to more than the speed of light? (viewed 22981 times)
  579. Could there have been multiple Big Bangs at different places in the universe? (viewed 22906 times)
  580. What kind of telescope should I use for astrophotography? (viewed 22876 times)
  581. How are astronomy and poetry linked? (viewed 22866 times)
  582. Could dark energy come from matter anti-matter pairs forming spontaneously and then annihilating? (viewed 22773 times)
  583. Why is NASA shutting down the Hubble Space Telescope? (viewed 22698 times)
  584. Can I listen to the SETI@home radio signal? (viewed 22689 times)
  585. How can you tell if a crescent moon is preceding or following a new-moon phase? (viewed 22636 times)
  586. Does the Sun have any heavy elements? (viewed 22575 times)
  587. Are the properties of extrasolar planets known? (viewed 22535 times)
  588. What class of spiral galaxy is the Milky Way? (viewed 22437 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 22432 times)
  590. Will we discover an 11th planet? What would it be called? (viewed 22399 times)
  591. Can the theory of formation of the solar system explain all the observables? (viewed 22387 times)
  592. What month was it when Odysseus saw Orion in 1000BC? (viewed 22325 times)
  593. How do astronomers observe the Sun's interior? (viewed 22203 times)
  594. What makes a satellite geosyncronise itself with Earth's orbit? (viewed 22053 times)
  595. Why does one side of Mars look more catastrophic than the other? (viewed 22048 times)
  596. Why does the apparent density of galaxies drop off at larger distances? (viewed 22019 times)
  597. Where was the water in the big bang? (viewed 21993 times)
  598. Is it possible for amateurs to do optical interferometry? (viewed 21969 times)
  599. Would a planet near the galactic center have a brighter night sky? (viewed 21952 times)
  600. Could we send a manned mission to the outer planets? (viewed 21880 times)
  601. Do stars' orbits in galaxies obey Kepler's Laws? (viewed 21751 times)
  602. What is the solar cycle? (viewed 21741 times)
  603. Can other terrestrial moons be (or have been) stable? (viewed 21661 times)
  604. How can water be chemically trapped in rocks? (viewed 21633 times)
  605. Why was the Platonic year named after Plato? (viewed 21632 times)
  606. How are supernovae discovered? (viewed 21568 times)
  607. Why do spacecraft need heat shields coming back to Earth but not leaving? (viewed 21544 times)
  608. What would the Big Crunch look like to an observer on Earth? (viewed 21539 times)
  609. Why are accretion disks flat? (viewed 21501 times)
  610. Can a black hole come back to the visual universe through a "little bang"? (viewed 21495 times)
  611. What is meant by "stopping down a telescope"? (viewed 21431 times)
  612. Does inflation allow for an infinite number of universes? (viewed 21428 times)
  613. Could our position in the universe affect our perceptions of the expansion? (viewed 21374 times)
  614. Why doesn't the hydrogen on Jupiter explode? (viewed 21317 times)
  615. How can the Sun have such a strong gravitational field if it's made of gasses? (viewed 21195 times)
  616. Have astronomers observed any phenomena that could be produced by extraterrestrial civilizations? (viewed 21106 times)
  617. Did I find a rock that came from the Moon? (viewed 21102 times)
  618. What is the SU(3) quark model? (viewed 21065 times)
  619. Can gravitational lensing from intervening galaxies cause the observed ripples in the Cosmic Microwave Background? (viewed 21041 times)
  620. Does a photon observe other photons moving past it at the speed of light? (viewed 21012 times)
  621. Will I be able to see the shadow of the Moon streaking towards me in a total solar eclipse? (viewed 20855 times)
  622. What's new with the Big Bang? (viewed 20770 times)
  623. Could photons be dark matter? (viewed 20703 times)
  624. How can we find galaxies behind the Milky Way? (viewed 20665 times)
  625. Is it possible to build a cheap device to measure declination? (viewed 20642 times)
  626. Why search for only Earth-like life on other planets? (viewed 20613 times)
  627. Why can we have solar eclipses? (viewed 20611 times)
  628. If comets are boiling away, why are there any left? (viewed 20584 times)
  629. How fast do particles travel in space? (viewed 20579 times)
  630. Why is the WMAP picture of the CMB an ellipse? (viewed 20525 times)
  631. Why do some eclipses take longer than others? (viewed 20502 times)
  632. Where can I find information on the moons of other planets? (viewed 20496 times)
  633. How much power is contained in a beam of light? (viewed 20447 times)
  634. Why is pressure broadening greater in low mass stars than in high mass stars? (viewed 20299 times)
  635. What would an "open geometry" for the universe look like? (viewed 20215 times)
  636. What are the boundaries of the constellations? (viewed 20210 times)
  637. Did the Sumerians measure precession? (viewed 20165 times)
  638. Can planets collide with one another? (viewed 20110 times)
  639. What kinds of star clusters are there? (viewed 20088 times)
  640. Why is the Cosmic Microwave Background not absorbed by interstellar hydrogen? (viewed 20034 times)
  641. Do constellations looks the same from space? (viewed 20028 times)
  642. How do astronomers come up with their facts? (viewed 20023 times)
  643. Why aren't discoveries of extrasolar planets reported on the news? (viewed 20014 times)
  644. How do bars form in spiral galaxies? (viewed 19974 times)
  645. Why don't astronauts sublimate in space? (viewed 19973 times)
  646. How do photons from distant objects maintain enough energy to reach us? (viewed 19945 times)
  647. Can HST see the Oort cloud? (viewed 19851 times)
  648. Do electrons age? (viewed 19825 times)
  649. How did Mars get so dusty? (viewed 19823 times)
  650. Can the Space Shuttle abort and return to Earth before reaching orbit? (viewed 19710 times)
  651. Can we make a movie of the Milky Way galaxy's rotation? (viewed 19709 times)
  652. What are collections of galaxies called? (viewed 19701 times)
  653. How long is twilight on the Moon? (viewed 19631 times)
  654. Does the shuttle worry about space junk? (viewed 19541 times)
  655. Will astronauts ever be able to go ice-skating on Europa? (viewed 19513 times)
  656. How does melting a material reset its radioactive clock? (viewed 19510 times)
  657. Why do supernova remnants look like rings rather than spheres? (viewed 19474 times)
  658. Where can I see Newton's original reflecting telescope? (viewed 19436 times)
  659. How do you classify galaxies? (viewed 19425 times)
  660. Why don't all neutron stars become pulsars? (viewed 19400 times)
  661. How can we understand the meaning of large numbers like "a million million?" (viewed 19317 times)
  662. Why doesn't SETI concentrate its observations to the nearby stars and the solar systems that we are discovering? (viewed 19291 times)
  663. What is the best time of the year to see eclipses? (viewed 19270 times)
  664. Will the next generation telescope OWL be able to detect an Earth like extrasolar planet? (viewed 19189 times)
  665. What causes a particle to decay? (viewed 19178 times)
  666. How can I nominate myself for a Nobel Prize in Physics? (viewed 19093 times)
  667. How long has humanity known that we live in a galaxy similar to others in the Universe? (viewed 19049 times)
  668. Will the Leonid meteor shower go away? (viewed 19021 times)
  669. Why is it called astronomy when all the other sciences end in -ology? (viewed 18979 times)
  670. What are "curled" dimensions? (viewed 18916 times)
  671. How does the color index of a star relate to its actual color? (viewed 18867 times)
  672. Is light of different colors affected differently by gravity? (viewed 18855 times)
  673. What was that eclipse I saw in the sky? (viewed 18757 times)
  674. How does interferometry work? (viewed 18749 times)
  675. If photons have zero mass, why do they feel the effects of gravity? (viewed 18700 times)
  676. How do distant galaxies differ from those nearby? (viewed 18671 times)
  677. If nothing can escape a black hole, why do some black holes have jets? (viewed 18663 times)
  678. Do asteroids ever do anything good in the Solar System? (viewed 18644 times)
  679. Does the temperature of matter increase as it is accelerated to relativistic speeds? (viewed 18631 times)
  680. What kind of interference must astronomers contend with when observing? (viewed 18609 times)
  681. How do we find out about the star formation histories of galaxies? (viewed 18601 times)
  682. What would happen if you went back in time and killed your grandmother? (viewed 18583 times)
  683. Wouldn't the vast distances of space distort SETI signals into unintelligeble forms? (viewed 18568 times)
  684. Are black holes spherical? (viewed 18556 times)
  685. Can astronomers observe anything when the moon is full? (viewed 18532 times)
  686. Why will fusion wait until hydrogen is gone before starting to fuse heavier atoms? (viewed 18429 times)
  687. How can I watch the Perseid meteor shower? (viewed 18423 times)
  688. Do we really observe the edges of galaxies at different epochs? (viewed 18363 times)
  689. What do stellar classifications mean? (viewed 18345 times)
  690. Can you tell me the characteristics of W, R, N and S type stars? (viewed 18334 times)
  691. How are astronauts trained for weightlessness? (viewed 18261 times)
  692. What is the three-body problem? (viewed 18221 times)
  693. Why aren't accretion disks around giant stars as hot as accretion disks around black holes? (viewed 18166 times)
  694. If the universe is "bounded" today, could it one day become "unbounded"? (viewed 17999 times)
  695. Will the diameter of a cluster of galaxies change with redshift? (viewed 17974 times)
  696. Is cosmic expansion happening on microscopic scales? (viewed 17802 times)
  697. How can I find out if the new moon has been sighted? (viewed 17675 times)
  698. Could neutrinos be dark matter? (viewed 17504 times)
  699. Do we have to worry about relativity when studying galactic objects? (viewed 17475 times)
  700. What kinds of cancer research have been done in space? (viewed 17328 times)
  701. When measuring the expansion of the universe, do astronomers consider that they're seeing how galaxies moved long ago, not today? (viewed 17284 times)
  702. How does a star take mass from another star? (viewed 17206 times)
  703. Does lunar gardening really work? (viewed 17200 times)
  704. How do supernovae show us that the Universe's expansion is accelerating? (viewed 17096 times)
  705. Could the Universe's dark matter be made up of black holes? (viewed 17056 times)
  706. How can you tell the difference between single and multiple extrasolar planets? (viewed 17008 times)
  707. What is Hot Dark Matter theory? (viewed 16932 times)
  708. Is it a coincidence that we can have total solar eclipses? Are there other planets which also have them? (viewed 16600 times)
  709. Is the green flash real? (viewed 16529 times)
  710. How does libration allow us to see more than 50% of the Moon? (viewed 16437 times)
  711. What is the photoelectric effect? Why can't multiple low-frequency photons free an electron? (viewed 16422 times)
  712. How can observations of the distant universe prove that the expansion is accelerating *now*? (viewed 16409 times)
  713. How do we know the density of some extrasolar planets? (viewed 16399 times)
  714. What happens to the helium formed in the sun? (viewed 16387 times)
  715. Is light blueshifted when it is gravitationally lensed? (viewed 16274 times)
  716. Do binary or triple star systems form together? (viewed 16224 times)
  717. No matter how fast the universe is expanding, shouldn't gravity eventually make it recollapse? (viewed 16195 times)
  718. What percent of the time can astronomers observe without interference from the Moon? (viewed 15971 times)
  719. What do meteorites tell us about life on other planets? (viewed 15945 times)
  720. Why is it easier to see a star if you look slightly to the side? (viewed 15863 times)
  721. Could matter-anti-matter repulsion power the expansion of the universe? (viewed 15703 times)
  722. Can we prove that the Moon isn't hollow? (viewed 15686 times)
  723. If the sun went out and our atmosphere froze solid, what color would it be? (viewed 15674 times)
  724. Why doesn't the ammonia and methane in Jupiter's atmosphere sink into the core? (viewed 15496 times)
  725. Are there any 'lonely galaxies'? (viewed 15323 times)
  726. How do we detect incoming meteorites? (viewed 15284 times)
  727. What was different on Mars in the past to allow liquid water to be present? (viewed 15198 times)
  728. When will Hale-Bopp return? (viewed 15062 times)
  729. Why don't skydivers burn up like meteors? (viewed 15058 times)
  730. Has anyone ever seen a star "turn on"? (viewed 14804 times)
  731. How has light from 13 billion years ago not passed us by? (viewed 14636 times)
  732. During close approaches, can Mars appear in our sky as large as the Moon? (viewed 14599 times)
  733. Why are craters round? (viewed 14403 times)
  734. How are planets affected by the Hot Ionised Medium? (viewed 14392 times)
  735. Can the sun rise from the west on Mars? (viewed 14034 times)
  736. What are the largest radio wavelengths observed from radio sources in the sky? (viewed 13934 times)
  737. Why was Mir burnt up in the atmosphere? (viewed 13933 times)
  738. How can we discern different galaxies/clusters along the same line of sight? (viewed 13830 times)
  739. What time is sunrise/sunset or moonrise/moonset at my location? (viewed 13704 times)
  740. What is the relationship between the width of a star trail on a photo and the star's intensity? (viewed 13403 times)
  741. Can we harvest H & O from space to make water? (viewed 13113 times)
  742. 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 12714 times)
  743. Why does Titan, in spite of being smaller than Mars, have an atmosphere more dense than Earth's? (viewed 12643 times)
  744. What is between the Oort cloud and the closest star? (viewed 12619 times)
  745. Could a planetary system survive if its star merged with another, or if its star went supernova? (viewed 11762 times)
  746. Are there solar tides? (viewed 11724 times)
  747. Does weightlessness affect hunger? (viewed 11575 times)
  748. Is Earth-moon tidal friction causing global warming? (viewed 11245 times)
  749. What happens to the Earth as the moon gets farther away and will it ever go away entirely? (viewed 11115 times)
  750. Do planets radiate noise? (viewed 10983 times)
  751. Is the moon spherical? (viewed 10903 times)
  752. Is dark energy affected by black holes? (viewed 10725 times)
  753. What would happen if a nuclear-powered shuttle exploded? (viewed 10537 times)
  754. Why is the Moon higher in the sky in winter and lower in the summer? (viewed 10294 times)
  755. Where are the protons and electrons in a Neutron Star? (viewed 10063 times)
  756. Wait, I'm still confused why information can't travel faster than the speed of light. (viewed 9660 times)
  757. Is the Moon always visible during winter on the North Pole? (viewed 9621 times)
  758. Do more meteorites fall at low latitudes? (viewed 9582 times)
  759. Did the Moon or planets form in a manner similar to that of Earth? (viewed 9558 times)
  760. What are the possible ends of the universe? (viewed 9447 times)
  761. Will Comet Elenin (C/2010 X1) affect the Earth on its close approach in Fall 2011? (viewed 9436 times)
  762. Will the Pioneer and Voyager probes ever leave the Milky Way? (viewed 9409 times)
  763. If there are infinity universes, will every thing that is possible happen? (viewed 9308 times)
  764. Is it sensible to consider terraforming Mars? (viewed 9289 times)
  765. What color are meteors? (viewed 8909 times)
  766. Where is everybody? (viewed 8538 times)
  767. Why does Mars have a dusty atmosphere? (viewed 8108 times)
  768. The naming of Mars (viewed 7992 times)
  769. Does the singularity in a black hole create a new Universe? (viewed 7943 times)
  770. If I were traveling through space, could I see distant galaxies with my own eyes? (viewed 7939 times)
  771. Is the reddish dust of Mars biogenic? (viewed 7794 times)
  772. Where is the Spitzer Space Telescope? (viewed 7177 times)
  773. When will humans travel to Mars and revisit the Moon? (viewed 7060 times)
  774. Does the particles involved in a star's final core collapse travel faster than the speed of light? (viewed 6401 times)
  775. How likely is it for a planet to transit its star? (viewed 6332 times)
  776. When is the best time to observe zodiacal light? (viewed 6196 times)
  777. Why do astronomers use telescopes? (viewed 6181 times)
  778. What causes the aurora? (viewed 6086 times)
  779. How did a transit of Venus provide astronomers with the first measurement of the Earth-Sun distance? (viewed 5065 times)
  780. Can the Sun be closer to the Earth than any planet is to Earth? (viewed 4406 times)
  781. Cosmologists say the expansion of the universe is accelerating, what is driving this? (viewed 3874 times)
  782. Can we hear sound on Titan? (viewed 3729 times)
  783. Does the direction of the moon's crescent change through the night? (viewed 3547 times)
  784. What do all the angles in a table for a planet's orbit mean? (viewed 3399 times)
  785. How do I maximize my chances of seeing shooting stars? (viewed 2707 times)
  786. Are exoplanets real? (viewed 2377 times)
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