steponit
01-15-05, 01:48 PM
As i understand relativity. if you shine a flash light at the equator aiming the beam straight up, then it would tend to curve arould the earth; however if you were at a point above the north pole , could you see the flash light if you looked straight into the beam?
guthrie
01-15-05, 02:03 PM
It would go straight up from both the equator and the north pole, and if you were a few thousand miles directly above either you could still see it. THe light would curve if it was at right angles to the centre of mass, whereas if you are looking straight up from the equator or the pole, the mass of the earth is still directly below you.
steponit
01-18-05, 04:01 PM
sorry, i guess i didn't make myself clear. a beam of light were aimed straight up from the equator, passing the north of the earth, then could i see the flashilight if i were north of the earth, looking directly into the beam?
Iron Sun 254
01-18-05, 04:56 PM
That still doesn't make sense. Relativity states that space-time is curved around a body so that if a beam of light were shone past the Earth it would bend slightly (very slightly)
river-wind
01-21-05, 12:28 PM
edit: screw it. I tried to do a ASCI graphic of light being bent by earth gravity, but couldn't get the code tags to like my spacing. so nevermind.
http://www.amnh.org/exhibitions/einstein/gravity/spacetime.php
The photons of a lightsource, pointed out from the surface of the earth, would be effected by Earth's gravity. But they would not be effected enough to cause the light beam to bend all the way back into the earth' surface again. The gravity we have isn't strong enough for that.
Now, if we lived on a planet w/ the gravitational pull of a black hole, then shining a flashlight upwards would result in the light beam coming back down; as a bullet would.