Is the universe an open or closed system? Assuming that the universe went from being in a chaotic state to a more orderly one, then the universe would need to be open, by the converse of the 2nd law of thermodynamics. But also, the universe does not receive any energy from an outside force. Thanks a lot in advance.

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anonymous · Answer

Closed system: don't worry about change in entropy, as entropy's not all about order, there are other considerations. No energy in or out, no matter in or out = closed system.

anonymous · Answer

to continue the use of traditional astrophysics, you have to use the close system approach.  if as ALL other sciences you want to relate findings between them, then only an open system can help.