On Thu, 10 Jul 2003, George Kinley wrote:

if there is no Atmosphere, where do rockets that go in Space get thrust from

Stand on a skateboard on a smooth flat surface, with a bag of rocks. Throw
the rocks in one direction, and you'll go in the other direction (except
for the inconvenient effects of friction - use bigger rocks and you should
see an effect). The rocket works exactly the same way. Throw mass away in
one direction, and you go in the other direction. "Conservation of
momentum" is what it's all about.

--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html