Thursday, March 29, 2007

Relativity Links

Neat pictures and graphs

Einstein himself on the subject, a popular account.

3 comments:

Anonymous said...

I have a Question, if you could travel at or faster than the speed of light, would you be able to travel back in time or would time no longer exist.

pleclair said...

There are some "trivial" ways that faster than light speeds are possible. A good discussion can be found here.

"Faster than light travel" is hard to even define properly, but one consensus is that while apparent faster-than-light velocities are possible, transmitting information faster than light is probably not.

In other words, one probably can't use faster than light travel, at least not in any known way.

Unfortunately, this is not really an answerable question at the moment. Even the theory of relativity breaks down at this point. Theoretical physics as we understand it seems to leave open the possibility of both time travel and faster than light speeds. There are theories that would answer your question both ways, and no one yet knows how to prove or observe the correct answer.

Traveling backward in time seems like a long shot, if for no other reason than it would violate causality.

I'll see if I can find some more satisfying explanations for Tuesday, but at the moment I don't know of a good answer to this question!

pleclair said...

One more thing: Prof. Paes gave a talk on this subject this past Tuesday, and has some good answers to exactly these sorts of questions:

PDF here

He is far more an expert on this topic, this is one of his areas of research.

Based on what we discussed today in class, you should follow most of the slides I think.