But if at a LaGrange point you don't need as much energy to keep up as the sum of gravitational forces acting on you is near zero. Ok, say there was a really large wall between you and something very very massive. Would the massive things gravity pull you up against the wall? or would the wall block the gravity?

I don't see your point I'm afraid. If you had say a mass flaoting in space, a large wall and behind that a star the Star exerts a force on the mass and wall. The wall exerts a force on the Star and Mass. The Mass exerts a force on the Star and wall. The largest object exerts the largest force and attracts everyhting to it.

What happens is that an object orbiting the Earth has 3 forces acting on it. Force of gravity from the Earth, Sun and Moon. The forces from the Sun and Moon are negligible in most cases. If you do the maths of this 3 body problem you find there are 5 points at which the 3 forces cancel. That is not to say there is no gravity, just no force. These are the LaGrange points. Anything placed at a LaGrange point will tend to stay there without assistance. Look it up on the Web.

There is nothing magical about this. Gravity is that which exerts a force on you, forces can cancel each other. A satellite in orbit stays in orbit because the force due to angular acceleration around the Earth negates the force of gravity. There is no force on the satellite yet gravity still acts on it. If you take either force away the satellite either drops in free fall or shoots away into space.

Can anything block Gravity

short answer is NO.

Yelmalio

• Re: Regarding your satellite. - Zephram_Cochrane/">Zephram Cochrane - November 16, 1999 - 15:33 UTC