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# What would you see while looking into a mirror while travelling almost speed of light? (see details for more)?

What would you see if you were looking into a mirror while travelling through space and gradually approaching the speed of light? What would the image in the mirror show? And additionally, what would you see?

Relevance

When you look in a mirror you see yourself in the past by the amount of time it takes for light to travel twice the distance from you to the mirror.

If you approached the mirror at any speed you would be reducing the distance you were seeing into the past.

At the speed of light nothing would be visible until you impacted the mirror,you wouldn't be looking into the past.

Since you say gradually approaching I will assume that any effects due to acceleration may be ignored (other than the obvious one that your speed is increasing). All a mirror does is reflect light and according to Einstein the speed of light is the speed of light no matter what speed you happen to be travelling at. So the mirror would really do nothing but reflect to you what you could see with your own eyes. Now that is the more interesting question, just what effects would you see? Since you are moving with the mirror you would appear as you always do and the things in your spaceship, no change.

Relativity talks about length contraction in the direction you are moving in. So things in the forward, and backward directions would appear to be closer than if you were not moving. And the faster you go the closer they would appear. Imagine a grid of points, a cube to begin with. As you move faster and faster that cube would squish in the direction you are moving and get thinner and thinner and thinner. So it would be with real objects. Stars, galaxies would appear closer and closer.

That is one thing. Anothewr has to do with what is called aberration. The effect can be seen in astronomy when a telescope has to be pointed at a different angle to a star than directly at the star. It has to do with the speed of light being a constant and the earth moving through space. This would tend to make things appear lower than they actually are. In fact, according to relativity, it tends to move the apparent position of objects towards the direction in which you are traveling. Close to the speed of light and you could look ahead and see stars, etc that are really behind you. Except any that are directly behind you would not be affected by this.

So these effects would compress things and shift things so that there would be darkness across most of the sky as you approach the speed of light and everything is shifted so it appears directly in front of you. And then there is the Doppler effect. If you are moving towards a source of light then the light will appear bluer and likewise if moving away it will appear redder. So there will be these color effects on top of these others. I would think the sky would compress into a band blue towards the front edge and red at the back that compresses from back to back as you move faster and faster. And that includes more and more objects due to the length contraction. Or something like that.

Check the sources. Although the C-ship one says something about the space ship appearing like a cone because of ength contraction it will really appear to be rotated. The faster an object moves, if you are observing it from far away, the more rotated it will appear. This was not realized until the 1950s when someone actually analyzed it from the point of view of actually looking at something moving really fast. Before that time people thought you would simply see an object as being squished, flattened. Not so.

One of the basic postulates of the theory of special relativity is the speed of light remains the same regardless of your frame of reference. To you, moving closer and closer to that speed, the mirror you're holding in your hand will always cast your reflection back at you normally.

To an observer outside your frame of reference, the image from the mirror will be distorted, its color gradually shifting to the red end of the spectrum.

What's more, suppose that while looking at your stunning reflection, you're combing your hair. You count 1 stroke of the comb every second. To the outside observer, it's more like one stroke every 5 or 6 seconds with the length between strokes ever increasing as your speed goes up.

• Anonymous

ALSO, depends on which way the mirror is pointing, and your position RELATIVE to the mirror.

see Einsteins explanation in the ' train ' theory where he describes how the speed of light, and indeed time itself are not constants, but rather " relative to the observer."

• Anonymous

If i'm not mistaken, Einstein claimed that we might seem invisable on the mirror as light is not fast enough to reach and get reflected back from the mirror to reach our eyes.

• Anonymous