Most popular questions

137 How much gold is there in our sun? 2018-01-19T08:19:35.130

124 How loud would the Sun be? 2015-12-15T00:51:33.153

86 Does the Sun rotate? 2013-09-25T15:46:34.720

85 How can there be 1,000 stellar ancestors before our Sun? 2016-06-21T16:38:10.857

85 Why is the discovery of merging neutron stars important? 2017-10-16T17:31:12.293

80 Why don't astronomers use meters to measure astronomical distances? 2017-03-20T15:38:30.147

75 Could the dinosaurs have seen the asteroid that killed them? 2018-01-31T22:58:00.787

73 Is the moon only 60 pixels? 2014-05-09T15:14:16.523

69 Why is only one side of the Moon visible from Earth? 2013-09-24T19:31:17.000

68 How does the Earth move in the sky as seen from the Moon? 2014-12-01T19:15:42.050

67 Why not take a picture of a closer black hole? 2019-04-10T23:44:51.460

67 Can gravitational waves pass through a black hole? 2019-04-21T17:21:58.067

66 Is it dark inside the Sun? 2020-03-05T20:18:38.157

62 Does the Milky Way move through space? 2017-09-12T17:51:45.460

61 If a massive object like Jupiter flew past the Earth how close would it need to come to pull people off of the surface? 2019-05-27T00:27:18.087

61 Why is there a zig-zag in elemental abundances? 2020-10-28T00:30:47.047

58 How many planets are there in this solar system? 2013-10-08T23:43:31.327

58 When will the Sun end all human life on Earth? 2016-08-10T19:26:56.097

58 Why is the asteroid belt shaped like a triangle? 2020-02-12T12:55:13.380

57 Would we have more than 8 minutes of light, if the sun "went out"? 2019-09-28T09:40:10.980

55 Why hasn't the "9th Planet" been detected already? 2016-01-23T01:36:35.630

55 If two black hole event horizons overlap (touch) can they ever separate again? 2019-06-24T21:26:14.230

55 What is the hottest thing in the universe? 2019-08-13T16:55:24.043

54 Where did TRAPPIST-1a go? 2017-02-23T09:19:14.810

53 Why does Io cast a hard shadow on Jupiter, but the Moon casts a soft shadow on Earth? 2020-05-22T12:03:41.727

52 Why is moon light not the same color as sunlight? 2018-06-27T15:10:42.440

52 If light has no mass, why is it affected by gravity? 2019-01-11T10:21:25.150

52 Sun constantly converts mass into energy, will this cause its gravity to decrease? 2020-02-25T03:26:50.310

51 What would happen if an ice cube is left in space? 2014-05-04T15:01:12.820

51 Is there any role today that would justify building a large single dish radio telescope to replace Arecibo? 2020-12-07T15:55:08.380

50 Why does it take so long to transmit an image from New Horizons to Earth? 2019-01-02T02:31:06.520

50 Is there a star over my head? 2019-09-08T14:38:52.483

49 Why has Venus's atmosphere not been stripped away by solar wind? 2013-10-14T14:30:22.200

49 How powerful a telescope would allow me to view the astronauts aboard ISS do a space-walk? 2013-10-16T13:37:49.987

49 How did Astronomers deduce that the Sun was not a ball of fire? 2020-05-24T14:00:27.730

48 Two species of dark matter? 2013-10-25T15:45:17.243

47 If Earth is tilted, why is Polaris always above the same spot? 2019-04-28T16:46:19.977

45 How can 'HD 140283' be older than the universe? 2016-12-19T09:33:06.120

45 Does the Milky Way orbit around anything? 2019-07-02T11:53:19.607

45 Why is Mars cold? 2019-10-09T11:03:27.917

44 Is it possible to achieve a stable "lunarstationary" orbit around the moon? 2017-03-22T12:21:39.960

44 Does the sun cross other spiral arms in its movement around the galaxy's center? 2019-11-12T12:57:55.360

43 What is in the center of the universe? 2013-10-16T15:44:06.363

43 Why do Black Holes in the middle of galaxies not suck up the whole galaxy? 2017-12-19T15:41:02.040

42 Where does the Solar System end? 2014-10-04T15:32:43.693

42 Why does gas form a star instead of a black hole? 2017-06-27T16:59:53.640

42 How do we have photos of galaxies so far away? 2017-09-10T15:53:07.167

42 How old is the oldest light visible from Earth? 2018-04-10T00:40:13.947

42 Why does the Sun have different day lengths, but not the gas giants? 2019-03-22T02:38:32.203

42 Are photons aged? 2020-02-23T14:45:56.133