# Dark Matter and Velocity

1. Dec 17, 2007

### PRyckman

If I was travelling 60% of light speed in one direction,
and you were travelling 60% of light speed in another direction
We would be invisible to eachother correct ?

Is that all that dark matter is? matter in which the distance between us is increasing faster than light speed?

Last edited: Dec 17, 2007
2. Dec 17, 2007

### Hootenanny

Staff Emeritus
No, the speed of light as viewed from any frame of reference has a definite speed c.

3. Dec 17, 2007

### Janus

Staff Emeritus
No, in fact, from each of our perpectives, the other would only be traveling at:

$$\frac{0.6c+0.6c}{1+\frac{0.6c(0.6c)}{c^2}} = 0.882c$$

relative to ourselves. This is how velocities add under Relativity.