In article Pine.LNX.4.50.0307110958020.29738-100000
@kolmogorov.physics.uq.edu.au, says...
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).

Or increase the speed. Stand on the skateboard and fire a shotgun,
you'll move.

Marc