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[-] cloudless@feddit.uk 82 points 6 months ago

1000032866

By the way, in 2012, scientists on the LHC were able to create the highest man-made temperature, at an astounding 5 trillion K – the temperature of the universe moments after the big bang.

[-] skillissuer@discuss.tchncs.de 25 points 6 months ago

5500C? i thought it's not that much, chemistry can get you there

apparently not

thermite tops at some 2000C-something, and in any case can't work above boiling point of aluminum (2470C)

only in few cases of adiabatic flame temperatures reach above 4000C, and all in oxygen. highest listed in wikipedia is oxygen/dicyanoacetylene at 4990C. maybe some wacky highly fluorinated oxidizer will allow for even higher temperatures. adiabatic detonation temperatures also top out at some 4500C even for the most energetic explosives

so really only practical way to get to 5500C is through use of electric arc

[-] kbal@kbin.melroy.org 8 points 6 months ago

adiabatic detonation temperatures also top out at some 4500C even for the most energetic explosives

What if we pre-heat the room to 3000, then very quickly introduce the explosives and run away before detonation?

[-] skillissuer@discuss.tchncs.de 8 points 6 months ago

if there's no room left after measurement, did it really happen?

[-] Klear@sh.itjust.works 6 points 6 months ago

5 trillion K is a lot more than 5500 C.

[-] Noodle07@lemmy.world 2 points 5 months ago

He's talking about the surface of the sun

[-] Klear@sh.itjust.works 2 points 5 months ago

Oh, in the picture. I haven't realised it's a part of the parent comment, only read the text.

Makes way more sense then.

[-] HeckGazer@programming.dev 3 points 6 months ago

Surely a laser would be way more practical

[-] skillissuer@discuss.tchncs.de 7 points 6 months ago

depends on what do you want to heat up. hint: at 5500C you need to handle plasma anyway

[-] wahming@monyet.cc 2 points 6 months ago* (last edited 6 months ago)

You're only off by about 9 zeros.

[-] aeki@slrpnk.net 17 points 6 months ago

We should at least have referred to the corona instead of the surface.

When it comes to the opposite, the coldest temperature in the known universe has actually been man-made (also in lab settings).

[-] Scubus@sh.itjust.works 10 points 6 months ago* (last edited 6 months ago)

I only vaguely recall this, but I seem to remember reading that using lasers we can actually get things into the negative kelvins? Or maybe we get them so cold they become hot? TBH I can't remember and it confused me when I read it, but I remember it being a reputable source

Edit: yeah this is evidently a thing

[-] wahming@monyet.cc 2 points 6 months ago

That article needs an ELI5 section.

[-] Solemn@lemmy.dbzer0.com 4 points 6 months ago

Try this one, I found it easier to at least think I understand what it's talking about: https://www.quantum-munich.de/119947/Negative-Absolute-Temperatures

Basic attempt at eli16: Temperatures are defined by entropy, rather than kinetic motion like we're used to thinking. In certain constrained systems, it's possible to create a situation where there is a maximum energy state, and saturating the particles in the system such that they're all close to that state creates a situation where the entropy starts decreasing (the system is less disordered since all particles are at the same maximum energy). That state where the entropy is decreasing is where negative temperatures exist.

End attempt. Disclaimer, I'm probably wrong, having spent just a few minutes skimming these two articles and trying to summarize what I understood.

[-] jadero@mander.xyz 1 points 5 months ago

So is it merely a lame joke to compare this to two's complement math or is there something fundamental to be learned?

[-] Rodeo@lemmy.ca 8 points 6 months ago

How do we know what the layers of the sun and earth are, and how hot they are? What methods were used to gain (or theorize) this information?

[-] cogman@lemmy.world 27 points 6 months ago

The sun is based on physics and observing nebula and super novas. We know how much the sun weighs based on it's gravitational pull. We know what it's currently burning given the frequency of the light it emits. We know what generation it is based on the elements in the planets. And we know the contents of other stars by the light they emit when they explode and collapse.

We know the layers of the earth because we can bounce sounds off the earth's core to see how deep it is. We know roughly what it's made of because we know how much the earth weighs and that the earth has a magnetosphere (you only get that with certain metals).

The methods used are generations of built up knowledge in physics and astrophysics.

You can, of course, just google these questions and get better answers than my summation

https://manoa.hawaii.edu/exploringourfluidearth/physical/ocean-floor/layers-earth#:~:text=There%20is%20evidence%20that%20the,generated%20by%20earthquakes%20or%20explosions.

[-] Umbrias@beehaw.org 3 points 6 months ago

Loss and lots of science and math to model and simulate the sun in a variety of ways slowly weeding out the models that weren't making experimentally validated predictions. I'm not sure how many astronomers are around, especially sun focused ones, on Lemmy to answer you more specifically about the history of sun science.

this post was submitted on 18 Feb 2024
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