The second law of thermodynamics tells us that entropy increases, thus it seems that it's impossible for all the air in a room to just happen to have the right combination of movements to randomly end up in one corner. It seems to be forbidden by the second law.
On the other hand, the laws of physics are reversible. Let's say I sucked all the air in the room (using quite a bit of energy to do so) out in to a balloon, or a box, or something, and put said balloon into the corner of the room. Then I pop the balloon (or open the seal on the box). Now all the air rushes out and quickly fills up the room.
But given that the laws of physics are time reversible the opposite situation should also be possible: the air rushing from the room to the box (or balloon), and even the seal of the box closing (or the pieces of the balloon rushing together).
First, why doesn't this happen? Because it's incredibly unlikely. Of all the number of ways that the air in a room can be arranged, only an insignificanly tiny minority include behaviour of this sort, whereas the overwhelmingly vast majority all look pretty much the same. If you were to wait for this sort of thing to happen, you could wait for several lifetimes of the universe, and it wouldn't happen, but it's still possible. It's no less likely than the particular actual arrange of every atom in the room you're in, it's just more special, in that you can tell the difference between it and the others.
I'm posting the because a poster in another thread disagrees and says that it's not simply unlikely, it's impossible.
On the other hand, the laws of physics are reversible. Let's say I sucked all the air in the room (using quite a bit of energy to do so) out in to a balloon, or a box, or something, and put said balloon into the corner of the room. Then I pop the balloon (or open the seal on the box). Now all the air rushes out and quickly fills up the room.
But given that the laws of physics are time reversible the opposite situation should also be possible: the air rushing from the room to the box (or balloon), and even the seal of the box closing (or the pieces of the balloon rushing together).
First, why doesn't this happen? Because it's incredibly unlikely. Of all the number of ways that the air in a room can be arranged, only an insignificanly tiny minority include behaviour of this sort, whereas the overwhelmingly vast majority all look pretty much the same. If you were to wait for this sort of thing to happen, you could wait for several lifetimes of the universe, and it wouldn't happen, but it's still possible. It's no less likely than the particular actual arrange of every atom in the room you're in, it's just more special, in that you can tell the difference between it and the others.
I'm posting the because a poster in another thread disagrees and says that it's not simply unlikely, it's impossible.
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