30 lines
1.2 KiB
Markdown
30 lines
1.2 KiB
Markdown
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# Entropy
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TODO
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## Information Entropy
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TODO
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## Physics Entropy
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TODO
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**But WHY does entropy increase in time-forward direction?** One may ask if laws on nature are time-symmetric, why is the forward direction of time special in that entropy increases in that direction? Just WHY is it so? Well, it is not so really, entropy simply increases in both time-forward and time-backward directions from a point of low entropy. Such point of low entropy may be e.g. the [Big Bang](big_bang.md) since which entropy has been increasing in the time direction that's from the Big Bang towards us. Or the low entropy point may be a compressed gas; if we let such gas expand its entropy will increase to the future, but we may also look to the past in which the gas had high entropy before we compressed it, i.e. here entropy locally increases also towards the past. This is shown in the following image:
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```
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time
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^ future
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| . . . . . .. . . higher entropy (gas has expanded)
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| . . . . . .
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| . . . . . .
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| .. . .. ..
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| . .. ..
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|_________....__________ low entropy (gas is compressed)
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| .. . .
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| . . .. .
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| .. .. . .
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| . .. . . . .
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| . . . .. . . .. . higher entropy (we start compressing)
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v past
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```
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