Here is my curious question:  First lets set up a scenario. Take 2 satellites orbiting the Earth. These 2 satellites are both 
moving on the same perpendicular to the center of the Earth. The outside satellite is tethered in some way to the inside one. 

Is there a point where the gravity holding the out side satellite to weak to hold its velocity in orbit? This velocity is very 
important. It is this critical point where a tether is required to hold this 2nd satellite in the same orbit as the 1st satellite where 
energy potential exists.

Then with an instantaneous release of the second satellite; broken tether, how much energy; momentum, can be gained?
I say a lot of energy can be gained. Hence sling shot effect. 

Next what would happen if at the exact critical point of this release; change in velocity, a photon(virtual photon) is shot in the 
same direction of this release? 

Is this different from shooting a light beam from a moving train. And comparing it to another light beam shot in the same
direction at the same time from someone standing next to the train? Think about it. Back to page 1
Secret is Being Positive