# How the universe looks like at the speed of light

1. Oct 28, 2009

### yoelhalb

How those the universe physicly looks like close to the speed of light, is it a flat disk or something different. (NOTE I am not asking in measurments accurding to someone that is not traveling but rather how it looks to himself)

2. Oct 28, 2009

### MaxwellsDemon

I've seen a calculation that says everything looks rotated as you approach the speed of light. In other words, if you were passing by a star at close to the speed of light, it wouldn't look like an oval, it would still be round...just rotated compared to what it would be if you were at rest with respect to it. So I'm guessing the universe would still look like it normally does...just take every star and turn it a little bit.

3. Oct 28, 2009

### Bob_for_short

I think everything would look rather smeared.

4. Oct 28, 2009

### Pequinino

Because of Lorentz contraction, as you approached the speed of light, the universe would be compressed to a single plane, with no distance in the direction that you are traveling, but the same as it was in the other directions.

5. Oct 28, 2009

### gb00842

6. Oct 29, 2009

### Staff: Mentor

There are two primary optical effects, Doppler shift and abberation. The abberation will cause things that are to your side (in the "stationary" frame) to appear to the front. The Doppler shift will cause things in front of you to be higher wavelengths and things behind you to be lower wavelengths. If you are going fast enough there will be a ring where the cosmic microwave background radiation is shifted into the visible. Inside that ring you will see nothing as everything will have been blueshifted beyond the visible, outside that ring will be a region where the stars have not been blueshifted beyond the visible, but they will be affected by abberation. Looking directly behind yourself you may be able to see hard gamma bursts that have been redshifted into the visible.

7. Oct 29, 2009

### ZikZak

Except that at nearly c, there is nothing behind you to look at. Abberration moves all images into your forward field of view. There's a good video of optical effects here: