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Q & A: leaving quickly

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Most recent answer: 10/22/2007
Q:
I talked to my physics teacher about this, and his answer didnt make any sense, so I’ll ask you guys for help. Say I am on a space ship traveling away from earth at 99.99999% the speed of light. Now lets say I have a telescope that is looking at the earth, and it is a very powerful telescope, if I look at what the humans are doing, won’t they be going in extremely slow motion, almost still from my perspective. Now lets just say that somehow I was traveling faster than the speed of light, and I was traveling directly away from earth, and I once again had a telescope, wouldnt the earth be now going in rewind from my perspective. I know that it is impossible to travel faster than the speed of light, but I was just wondering what happened in each of these 2 questions. thanks.
- bran pivar (age 19)
purdue university, west lafayette, IN
A:
You're right that if you were leaving at nearly the speed of light, events on earth would go at a crawl from your perspective. You'd also need an interesting telescope, as all the light would be redshifted. At the speed you describe, light which is emitted from Earth in the visible spectrum ends up in the high end of the microwave spectrum. X-rays would be redshifted into the visible spectrum, but there aren't very many x-ray emitters on Earth and the atomosphere's transparency is best in the visible range.

You're probably sick of hearing this but we simply can't give any answer to your second question, any more than we could say what would happen if 2+2=5.

Mike W. (and a little from Tom)

(published on 10/22/2007)

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