Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: backwards time flow?

Learn more physics!

Most recent answer: 01/12/2014
Q:
Physicists say that time is moving foward because entropy always increases. But have physicists considered that we might be mistaken? Since there is no ultimate reference frame, it could be possible that we are in fact moving backwards in time, that entropy in reality decreases, that causality is just an illusion, that the Big Bang was actually the end of the universe and that from total disorder (predicted heat death of the universe) naturally comes order (the universe at t=0). I know it seems ridiculous that people begin dead, then assemble themselves into living being, live their life backwards, enter their mother's uterus and decompose back into sperms but I don't see any physical law that makes it impossible to happen. Maybe time doesn't move at all or it doesn't exist at all.
- Anonymous
A:

If you put together the effects you mention, it sounds like a whole lot would be different. But if you step back and look at the whole package, it really just amounts to changing the name of the direction of time, substituting "-t" for "t".

The other question ("Maybe time doesn't move at all or it doesn't exist at all") is more complicated. We know time exists as a special dimension the same way we know anything- we don't have any way to make sense of our experience without that idea. But why does time "move?", why does experience flow the way it does, rather than having the whole birth-to-death line all experienced together? We don't really know.

Mike W.


(published on 01/12/2014)

Follow-up on this answer.