How is "Absolute Zero" Obtained

[Kiali]

So I was thinking about cold temperatures lately, because of the early winter. I realized that for a temperature to be at absolute zero it can't gain any heat from its surroundings. But for that to be true, then we cannot create absolute zero here on earth because the earth itself will always provide some sort of heat from the surroundings (the core and such). So, then I thought that maybe a whole planet (somewhere out there) could be at absolute zero, but then wouldn't literally all of the planet have to be at that temperature? But couldn't the gases on the planet also contain heat? Including oxygen, so therefore, absolute zero can only be attained in a space with no oxygen (including other gases). But if that's the case then it could only be achieved in space? I think iv'e confused myself...thoughts?

[Strange]

10 hours ago, Kiali said:

I realized that for a temperature to be at absolute zero it can't gain any heat from its surroundings.

That is roughly right:

Quote

The laws of thermodynamics indicate that absolute zero cannot be reached using only thermodynamic means, because the temperature of the substance being cooled approaches the temperature of the cooling agent asymptotically,^[4] and a system at absolute zero still possesses quantum mechanical zero-point energy, the energy of its ground state at absolute zero. 

https://en.wikipedia.org/wiki/Absolute_zero

But we can cool things down to within a fraction of a degree of absolute zero, for example, 0.00036 K https://www.nist.gov/news-events/news/2017/01/nist-physicists-squeeze-light-cool-microscopic-drum-below-quantum-limit

This is many times colder than any naturally occurring temperature, in space or anywhere else. And even creating a perfect vacuum doesn't help, because you still have the equipment you are using to reduce the temperature, which will be above absolute zero.

That Wikipedia page mentions an even lower temperature:

Quote

A record cold temperature of 450 ±80 picokelvins (pK) (4.5×10⁻¹⁰ K) in a BEC of sodium atoms was achieved in 2003 by researchers at Massachusetts Institute of Technology (MIT).^[9

 

[swansont]

16 hours ago, Kiali said:

So I was thinking about cold temperatures lately, because of the early winter. I realized that for a temperature to be at absolute zero it can't gain any heat from its surroundings.  

And to shed heat, it requires the surroundings be at a lower temperature.

[Mordred]

8 hours ago, swansont said:

And to shed heat, it requires the surroundings be at a lower temperature.

At the OP, a very solid guideline in thermodynamics. Anytime you have a higher temperature, pressure or energy density you require a lower region for flow from one region to another. That flow will naturally occur.

 You'd be amazed at how far reaching into higher physics that dynamic occurs.

(Lol when you study enough, you realize the universe in all its dynamics seeks the lowest most uniform state). Just a side light perspective consideration.

 

Edited December 2, 2019 by Mordred