# Equivalence principle + light speed postulate =

1. Jun 24, 2004

### Loren Booda

It seems to me that Einstein's equivalence of gravitational acceleration and non-gravitational acceleration, when combined with his constancy of light speed in vacuuo, should yield a constancy of gravitational speed in vacuuo.

2. Jun 24, 2004

### HallsofIvy

Staff Emeritus
It's not necessary to appeal to the constant velocity of light or relativity in general.

F= G(gravitational mass A)(gravitational mass B)/r2

(inertial mass A)(acceleration of A)= F so as long as inertial mass= gravitational mass:

acceleration of a= G(gravitational mass B)/r2, a constant.

Last edited by a moderator: Jun 24, 2004
3. Jun 24, 2004

### Loren Booda

How does this show that the velocity of gravitational propagation is constant?

4. Jun 25, 2004

### Chronos

pick a constant, any constant. if you dont like c, take g. the math still works out to the same conclusion.

5. Jun 25, 2004

### Loren Booda

So where is the constant of velocity in Hall's equations?

6. Jun 25, 2004

### timetraveldude

All you have proven is that the acceleration due to gravity is dependent only upon the object causing the accelerationa and not the accelerated object. Loren's question has to do with the propagation speed of gravity. Perhaps Loren could explain more clearly what is meant by this.

7. Jun 26, 2004

### Loren Booda

The speed of light propagation is c. Propagation speed in general may be finite or infinite. Simply put, propagation speed is distance per the time that particle action takes to travel over that distance.

Here I hypothesize that