The Most Misunderstood Concept in Physics
Entropy, 1.07.2023
17:08
Ultimately, all the energy that reaches earth from the sun is converted into thermal energy, and then it's radiated back into space. But in fact, it's the same amount.
19:37
So right after the Big Bang, that is when the entropy was lowest
19:51
But the early universe was hot, dense, and almost completely uniform, everything was mixed and the temperature was basically the same everywhere, varying by at most 0.001%. So how is this low entropy?
20:15
Taking gravity into account, having matter all spread out like this, would be an extremely unlikely state, and that is why it's low entropy
21:09
The universe started with around 10 to the 88 Boltzmann constants worth of entropy
21:15
All the stars in the observable universe have about 9.5 times 10 to the 80
21:20
The interstellar and intergalactic medium combined have almost 10 times more
21:29
A lot more is contained in neutrinos and in photons of the cosmic microwave background
21:36
In 1972, Jacob Bekenstein proposed another source of entropy, black holes
22:49
The super massive black hole at the center of the Milky Way has about 10 to the 91 Boltzmann constants of entropy
23:06
All black holes together account for 3 times 10 to the 104 Boltzmann constants worth of entropy
23:14
Almost all the entropy of the universe is tied up in black holes
23:19
The early universe only had about 0.000000000000003% of the entropy it has now
25:26
Both low and high entropy are low in complexity. It's in the middle where complex structures appear and thrive
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