Viewing a single comment thread. View all comments

the_fungible_man t1_j67dkut wrote

Reply to comment by mfb- in In the absence of cosmic radiation, would an object placed in space eventually cool to absolute zero? by IHatrMakingUsernames

Does it reach 0 K by asymptotically approaching it for eons until, finally, the last photon departs?

10

mfb- t1_j67ij36 wrote

In principle yes. This would need absurdly long times for macroscopic objects. Could well be longer than the timescale of proton decays.

We also don't expect the temperature of space to ever reach exactly zero thanks to dark energy.

16

dubbzy104 t1_j67u1w1 wrote

Wouldn’t the CMB also stop the temperature of space from reaching exactly 0K. In trillions/quadrillions of years it may be very very low, but never 0K, right?

8

mfb- t1_j67ue0i wrote

It could drop so low that it won't stop the object from reaching its ground state, but if dark energy stays the way it is then there will always be some radiation in the universe.

6

dubbzy104 t1_j67uj1q wrote

True. So they both could eventually tend towards 0, but DE will generally be more energetic

2

Varsect t1_j680kxk wrote

I mean, dark energy isn't entirely necessary to avoid 0 Kelvin at all tbh.

2

cheses t1_j67hft1 wrote

Yeah should be approximately 0 K. The amount of radiation is a function of the bodies temperature.

2