Posted: Mar 25, 2019 4:06 pm
by Thommo
Hermit wrote:
Thommo wrote:
Hermit wrote:Yes, time will end. That's the theory currently held by astrophysicists anyway. They call it the heat death of the universe, or something like that.

I don't think that's right. I think it's an idea among many, which doesn't necessitate the end of time by a whole raft of definitions anyway.

Feel free to refute the second law of thermodynamics. It's only a theory, and I'm all ears.

I think we should leave the goalposts where they are: ... e_universe
Current status
See also: Entropy § Cosmology, and Entropy (arrow of time) § Cosmology

Proposals about the final state of the universe depend on the assumptions made about its ultimate fate, and these assumptions have varied considerably over the late 20th century and early 21st century. In a hypothesized "open" or "flat" universe that continues expanding indefinitely, either a heat death or a Big Rip is expected to eventually occur.[1] If the cosmological constant is zero, the universe will approach absolute zero temperature over a very long timescale. However, if the cosmological constant is positive, as appears to be the case in recent observations, the temperature will asymptote to a non-zero positive value, and the universe will approach a state of maximum entropy.[8]

If a Big Rip does not happen long before that, the "heat death" situation could be avoided if there is a method or mechanism to regenerate hydrogen atoms from radiation, dark matter, dark energy, zero-point energy, or other sources so that star formation and heat transfer can continue to avoid a gradual running down of the universe due to the conversion of matter into energy and heavier elements in stellar processes and the absorption of matter by black holes and their subsequent evaporation as Hawking radiation.[9][10]