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mfb- t1_j67cmbq wrote

If it doesn't receive any radiation and assuming the object doesn't decay in some way: Yes. It cools via the thermal radiation it emits.

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jonnyclueless t1_j67f4co wrote

Out of my depth here, but I believe absolute zero is impossible because you lower a temperature, you need something below that temperature. And since nothing can be colder than absolute zero, nothing can reach absolute zero.

But I would defer to a physicist, not me.

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mfb- t1_j67ij36 wrote

Replying to the_fungible_man (#1,546,878)

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.

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dubbzy104 t1_j67u1w1 wrote

Replying to mfb- (#1,547,513)

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?

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mfb- t1_j67ue0i wrote

Replying to dubbzy104 (#1,549,001)

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.

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_Jacques t1_j680f2o wrote

Well there just simply is no way for it took be totally sheltered from said radiation. Any thing you would try to encapsulate said object would itself receive some radiation, heat up a tiny amount, and reradiate it inside the capsule.

But yes assuming no cosmic radiation is coming in it would tend towards 0, but it will radiate slower and slower.

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Varsect t1_j680hi6 wrote

By the laws of physics nothing can approach (reach) 0 Kelvin because by that point,all thermal exchanges stop AKA atoms stop moving entirely (that's not the most accurate way to say it but for simplicity's sake) Our current understanding of Dynamics and Statistical Physics cannot allow for such things to exist in our universe. Nevermind anything below that.That is why it is absolute in temperature, so really, there is no necessary single fixed mechanism except for thermal exchange that can stop 0 Kelvin from being reached. Also, the uncertainty principle would be screwed.

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MxPunkin t1_j68j3ty wrote

Energy can neither be created or destroyed, so as long as the object had some heat to it, then it could never cool down to 0k because that initial heat it brought with it would be in the system somewhere. Unless you were to isolate the object, and then remove the energy from the quarantine, then that energy will still be in the system somewhere.

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Connect_Eye_5470 t1_j68oc0u wrote

The short answer is no. Soace isn't actually 'empty' and the answer has nothing to do with cosmic radiation. It has to do with kinetic energy. Particles will strike your 'object' and impart kinetic energy which will generate 'heat' due to friction basically. 'Barrier' levels are hard to meet. I.E. you need a lot if energy to heat water from 1 degree Celsius to 99 degrees Celsius. You need a lot more to actually make water boil and reach 100.

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Busterwasmycat t1_j68r4n9 wrote

How much time do you have? The only loss of energy (loss of heat) will be by radiation. There is no conduction and of course no convection. Energy emission by radiation will be from black-body radiation (the emission of "light" energy that depends on the temperature of the body itself).

As temps decrease, the energy being emitted decreases, so the temperature of the body would approach but never really reach the limit of 0 contained thermal energy, although after a huge amount of time, it would be close enough that you couldn't measure the difference. The death of the universe condition (everything at absolute zero or, actually, slightly above because absolute zero is not possible for other reasons) is trillions of years in the future according to estimates I have seen (never tried to calculate it myself; not exactly certain how to).

There is a minor problem with your question, because the black body emissions can be absorbed too, so even in the absence of big energy sources like stars, all matter is being bathed in a low amount of energy, which would counter the loss by emissions, through absorption of radiation coming from other objects. Not much energy, certainly, but still energy. Also, there is a lot of energy zooming around which was emitted ages ago and has yet to interact with matter, and all matter will encounter some of that energy and heat up slightly by absorbing it.

The role of collisions and conversion of energy of motion (kinetic energy) to heat (or kinetic energy at the atomic level, which is pretty much what temperature is truly measuring) would lengthen that cooling process as well. Cannot have true absolute zero if things are moving.

Simple answer is that isolated matter in space does not cool to absolute zero (or as close to that state as can be attained by matter). Stuff in space is a bit warmer, a few degrees warmer in the sparser regions of space and considerably warmer if there is a decent source of emitted energy nearby. Still usually extremely cold by our human standards though, just not absolute zero.

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AssCakesMcGee t1_j68rpdq wrote

Replying to Yaver_Mbizi (#1,552,905)

That's not a conventional definition of temperature. A particle gaining energy but losing entropy is strange, but it's not what people think when you say 'negative temperature' since these particles are indeed, quite hot.

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pacaruru t1_j692rkv wrote

Replying to MxPunkin (#1,553,015)

If we're talking absurdly long timescales it would eventually go to absolute zero as it's mass decayed into energy and it released that energy into a form that was no longer accessible or useful but by then it would be a bit of a stretch to say the object still exists any longer.

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Hakaisha89 t1_j69aq7h wrote

Short answer, no.
Long answer, we don't know.
We know all mass will eventually decay into a form, where it stops releasing parts of it mass, and when all mass in the universe stops producing heat, along with all energy in the universe being spent, you got the third form of heat which is the expansion of space itself, so eventually when this all stops, and all mass and energy would eventually spend all its energy and reach zero, roughly 1.7×10^106 years, in comparison, the age of the universe is 1.3787*10^10 years, however this is only true if the end of the universe is in the form of heat death, and that is also assuming that protons decay into a state of non-energy.
The other models of the end of the universe assumes that the universe will probably end in another way, earlier then the heatdeath, which basically means no.

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omegasix321 t1_j69ib2r wrote

No, the concept of an absolute 0 in the first place is purely mathematical/theoretical. It would be impossible to force a particle to have zero thermal, and therefore zero kinetic, energy in a quantum universe. Quantum randomness seems to be a fundamental facet of physics.

The only way to really do this would be to annihilate the universe in its entirety, so that there was no energy or matter at all. But then the concept of temperature would have no meaning.

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Party-Cartographer11 t1_j69l4l0 wrote

As stated, no. The object has heat as you ask if it would cool. Total heat would remain the same as energy cannot be lost. It would shed temperature until its thermal energy is in equilibrium with the universe. If it were the only object in the universe, universal temperature would be very close to absolute zero, but just above it by the amount starting thermal energy in the universe, divided by...the universe.

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big_sugi t1_j69uyfb wrote

Replying to [deleted] (#1,557,848)

When someone corrects your error, you could graciously accept it, or you can get defensive and pretend it wasn’t really an error.

The first way is much better, and it increases your credibility instead of diminishing it.

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QuantumCakeIsALie t1_j69wxbt wrote

Replying to AssCakesMcGee (#1,554,564)

It's a very conventional way to define temperature in thermodynamics/physics.

Fun fact, you could create infinite energy if you could create a Carnot thermodynamical cycle that crosses + and - temperatures. That was a big issue with the concept of negative temperatures, until someone proved that it's impossible to create such a cycle to begin with.

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Aarakocra t1_j69xwe4 wrote

Yes-ish. The concept of the heat death of the universe is the end result of that idea. The stars cool off and we are left with bodies that slowly cool down until things reach absolute zero and the universe is “dead”.

But that plays out over a long time. The body loses heat through the standard mechanisms of radiation (excitement at the atomic level results in photons jumping off), convection (fluid passes over the body and takes heat as it leaves), and conduction (something is in contact with the body and heat transfers through it). We would only be talking about radiation here, because this object is alone. Radiation happens based on how much activity is happening down at the atomic level, so the rate of cooling is going to decrease as the temperature decreases. However the radiation will happen at some point, so the body will eventually drop to absolute zero. We have a nonzero loss of energy, so as long as we have zero gain in energy it has to eventually hit zero.

At least assuming it is a true absence of cosmic radiation. This only holds as long as there is no input energy transfer taking place. Even a star far away could produce enough energy to keep the body from reaching absolute zero. The assumption of zero gain in energy is hard to pull off.

Also fun fact, you couldn’t observe the object at absolute zero either! As far as I know, we can’t measure such an object without giving back some energy.

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Chemomechanics t1_j69zwi7 wrote

Replying to buff-equations (#1,554,960)

As a side point, it's not. Such counters click down from 0 to the maximum count since they can't represent a negative. Temperature is different—arguably, the more fundamental parameter is the reciprocal 1/T, which is positive in most familiar systems but can in some circumstances swing below zero. This implies (very weirdly) that the temperature shoots up to ∞ and then to -∞. Again, it takes special effort to construct such a system; it won't occur around the house.

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TheDotCaptin t1_j6a04p4 wrote

Replying to _Jacques (#1,549,860)

What about going into the void between galaxies and waiting (long time) until the expansion of space between the next closes object is greater than the speed of light. At that point any light (EMR) aimed in this direction would never reach it.

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Chemomechanics t1_j6a0bhx wrote

Replying to jonnyclueless (#1,547,069)

>absolute zero is impossible because you lower a temperature, you need something below that temperature.

Fortunately, this isn't the reason, because it's not true. If you've ever been in 35°C weather or hotter, you lowered your own temperature without there being anything below that temperature. You probably didn't even think about it!

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XtremeGoose t1_j6b37o7 wrote

Replying to Yaver_Mbizi (#1,552,905)

That's because temperature as it's classically defined has a coordinate asymptote (at 0K). The fix used in quantum thermodynamics is to talk about thermodynamic beta which is the inverse of temperature, where heat flows from a low thermodynamic beta to a higher. That fixes the coordinate issue and you can cross easily from the classically to the quantum.

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Skarr87 t1_j6b791b wrote

You can never get to absolute zero only the ground state. Hat being said even in a perfect vacuum it will eventually radiate energy through electromagnetic waves like infrared until it gets to its ground state.

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sebzim4500 t1_j6ck159 wrote

Replying to AssCakesMcGee (#1,554,564)

What definition of temperature are you thinking of? The only definition I know is based on how the entropy changes with energy, which clearly makes negative temperature objects extremely hot.

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Varsect t1_j6hlvj0 wrote

Replying to Aarakocra (#1,561,428)

>Yes-ish. The concept of the heat death of the universe is the end result of that idea. The stars cool off and we are left with bodies that slowly cool down until things reach absolute zero and the universe is “dead”.

You can't reach absolute zero. Dark Energy is there, even without Dark Energy, subatomic particles will still be there, also, absolute zero on such scales and definitions would require true nothing to exist and we don't even know if that is possible

>However the radiation will happen at some point, so the body will eventually drop to absolute zero.

That's now how Thermodynamics works, at all.

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vellyr t1_j6krkft wrote

If an object had zero energy, then both its position and momentum would be known, violating the uncertainty principle.

I’m hoping a real physicist can help me out with this, but it seems like it would eventually stabilize at some non-zero energy.

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