Quote:
Originally Posted by Slickcraft
Well sort of free falling but countered by centripetal force. In classical Newtonian physics when the speed related centripetal force equals the gravitation force then a stable circular orbit is achieved.
http://www.physicsclassroom.com/Class/circles/u6l4c.cfm
All of those useful communications satellites are at a speed/altitude so that they orbit exactly once per day matching the earth's rotation hence "appear" to be parked in a fixed spot overhead. Of course the space station is in a much lower orbit and appears to zip along. |
I wasn't trying to get too technical, my point was it is simply free falling to Earth, like the Space Shuttle, but because of the Earth's rotation and the ISS speed it can never catch up. Centripetal force counters gravity. Although, occasionally a thrust is deployed to get back on course.
Great link. If you really like physics you can watch free physics classroom lectures from MIT on youtube.