Well firstly we have defined space to be whatever's affected by the 'big bang', so we do suspect that space (which is contained within the Universe) is indeed finite, and very large, not infinite.

As to whether space has an end: An equivalent question in many of our minds would be whether we would be able to ever 'leave' space if it were finite. As of now, this is unknown, but doubtful.

nice.rider: Small correction. The Doppler effect refers to the fact that the frequency of the incoming light (which is the case here for astronomical measurements) is increased if the body emitting it and us are moving towards each other [this is called blueshifting], and the frequency drops if the body emitting it and us are moving away from each other [this is called redshifting].

So yeah, your analogy would be to talk about a higher pitch when the ambulance comes towards you, and a lower pitch as it moves away from you

This post has been edited by bgeh: Aug 22 2009, 07:31 PM