### Re: mass and the bending of space

Date: Fri Oct 10 14:15:07 2003
Posted By: Bryan Mendez, Education and Public Outreach Scientist
Area of science: Physics
ID: 1061683226.Ph
Message:

Q:

```1. If we have two separated masses with a high gravitational pull between
them (bending space), is the space between the objects stretched? Also if
we took this to it's limit, would light ultimately be stationary in this
stretched space?
2. If the mass of an object bends space, does it also compress space,
where light would be "seen" to be traveling faster than c.
```

A:
Hello Jason,
I can essentially answer both of your questions together. One of the primary features of the Theory of Relativity, which describes the warping of space time caused by mass and energy, is that the speed of light is a constant no matter what. No matter how stretched or compressed space around you is, no matter how fast or slow you are travelling relative to a source of light, you must always measure the speed of light to be the speed of light.

The only thing that can make you think that the speed of light is different might be if light could pass between two mouths of a worm hole connecting two distant regions of spacetime. The worm hold essentially creates a short cut between the two points in spacetime. An observer outside the worm hole thinks light passes between the two points faster than it should have. But the light never actually travelled faster than c (300,000,000 m/s). It only took a short cut. It cheated.

There have been other solutions to the equations of the Theory of Relativity to suggest other such cheats are possible. But in all cases light itself always travels at a set speed through spacetime, no matter the shape of that space time.

I hope that helps.

All the best,
Bryan Méndez, UC Berkeley

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