Re: Stupid Astrophysics question

[Richard Baker]

Gord said:

> Ow. The whole idea hurts my head, though. But I gotta ask, when did
> our universe become a 4-space? (ie. can you explain how this was
> deduced? Everywhere I look I see a 3-space.) Or are you using time as
> a "dimensional" axis?

Yes, we're using time as a dimensional axis to make something called
spacetime. People moving at different speeds will carve this spacetime
up into space and time in different ways. I'm sure I've mentioned
before that I've written quite a lot of popular-science level stuff on
this for the Culture list; you can read it on the web at

http://www.mrao.cam.ac.uk/~rcdb100/physics/vbht/

(Adding plenty of other spacelike dimensions and "compactifying" them so
that they become so small that we don't see them is also a pretty
popular thing for theoretical physicists to do. If anyone's interested,
I'll repost a recent Culture message that I wrote on that subject too.)

Rich
GCU Irregular Series