arrow of time?

[darkkazier]

i listened to a discussion Michio Kaku was giving and he talked about a region of space where causality was reversed, where soup would boil in your stomach etc. He said it all had to do with something called the Arrow of time, and he said that in some regions of spce the arrow of time would be reversed. Can anyone elaborate on this?

[JPQuiceno]

"soup would boil in your stomach"

 

Huh?

 

Can YOU elaborate? I don't understand.

[darkkazier]

well, he said that things would not happen in "order". for instance you would eat soup, and instead of it aleady being cooked it would cook in your stomach, or instead of lgiht travelling into your eyes it would travel away basically things happen in reverse. Or, cake batter could unmake itself into its base components.

[danny8522003]

It is difficult to define an arrow of time, especially on a subatomic level because all processes can happen both backwards and forwards yet still be within the laws of physics. This could happen in the real world too. For example, you 'could' unstir sugar from your coffee or 'unshuffle' a deck of cards, the only problem is the likelihood of this happening is so small it can be ignored. I.e. the probability of further shuffling a shuffled deck of cards and getting them in the order you started with originally is about as likely as winning the National Lottery on 9 consecutive draws!

 

I read somewhere about the "arrow of time". It has something to do with entropy, which is a level of "orderedness", and the second law of thermodynamics. A low entropy is more "ordered" than high entropy. It is stated that the level of entropy must always increase within a system. E.g. unstirring the sugar would be an increase in entropy and would therefore violate the second law.

 

From this the arrow of time will always point towards increasing entropy and is known as the thermodynamic arrow of time.