Tuesday, May 02, 2006

The entropy argument seems to suggest that if we waited some insanely long amount of time the atoms in the coke bottle would eventually end up back in there.

I'd argue that the universe is based on cause and effect- nothing happens unless something makes it happen. The atoms in the coke bottle leave it because preassure differences cause them to move. Unless some force gathered these atoms and forced them back into the bottle, there is no reason they would ever re-enter the bottle, regardless of how long we wait for it to happen.

Whether the probability of getting that same collection together again randomly is huge or small is insignificant, they simply will not be put together again unless some force causes it to happen


Blogger linford86 said...

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5:38 PM  
Blogger linford86 said...

Actually, since the motion of the constituent atoms is entirely random, if you wait for a sufficiently long time, any system will take on just about any configuration. It is actually the case that the configuration of a collection of atoms, such as a gas, is determined entirely by statistics. This is the basis of things like thermodynamics and statistical mechanics.

I'm sitting in ITS, on a couch, as I write this. It's entirely possible that all the air in this room will collect in one corner, and that everyone in here will die because of it. However, the probability for such an event to occur is extroardinarily low. In fact, it's so long that it probably won't happen even if we waited for a few trillion years.

But it deosn't even matter what forces act on the gas molecules in this room - their motion is entirely random, no matter what. In fact, what we are really seeing on the large scale is simply just a statistical averaging of the behavior of all those constituent particles. If you take Physics 141, this is one of the things you'll talk about when you get around to doing a little statistical mechanics. I can remember Professor Wolfs giving an explanation similiar to the one I just gave - except that he said to imagine that all the gas molecules in Hoyt went to one corner of the room, killing all of us poor students.

In any case, the entropy "argument" isn't an argument at all - it's a statement about what is scientifically known to be true based on an idea that's been known for a very long time (since the 1850's.)

5:38 PM  

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