Speed increases mass, which increases gravity?

1. Jul 2, 2009

ledzeppie

So if speed increases mass as it approaches c, does the added mass increase the curvature of space-time? The reason why this question is making me confused is because the mass is only increased to an outside observer. Could anyone clarify this for me.

2. Jul 2, 2009

DaveC426913

Correct. Relativistic mass does not contribute to the curvature of spacetime.

3. Jul 2, 2009

Staff: Mentor

The source of gravity in GR is the stress-energy tensor which has 10 independent components, only one of which is mass. So mass, by itself, is not the source of gravity.

4. Jul 3, 2009

atyy

In SR, there is no gravity, and mass does not curve spacetime.

In GR, spacetime curvature is caused by the stress-energy tensor, whose components are frame dependent. The relativistic mass is one component of the stress-energy tensor in some frames, and so does curve spacetime. In frames in which there is no relativistic mass, this is made up for by changes in other components of the stress-energy tensor, so that the spacetime curvature remains the same regardless of frame.

Last edited: Jul 3, 2009