Jumping the Gun.

Hi Ste-Marie,

On Earth, in a car, we move by traction (friction). In space we can move in one of two ways, by external force, or by reaction force. External force so far as we know in the Solar System, can only be applied by Solar Wind, which is very feeble - and for which you would need large solar sails. Reaction force is the standard way to move in space, where you throw away a part of the mass of the system, and by Newtonian mechanics (The third law, to every action there is an equal and opposite reaction), you move in the opposite direction. That is why a mighty rocket delivers only a fraction of its original mass as payload - the rocket sacrifices itself to impart high velocity to the payload..

It is worth reviewing what we Indians call 'Fundas' once in a while. Half the mistakes scientists make is not in high-flown equations, but in simple things, so your questions are very pertinent.

Regards
Selvaraj