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Comment by LeratoAustini | Hacker News Reader

I often think about how cold our lifeforms on earth are, relative to temperatures of things in the universe. 0 Kelvin is theoretical lowest possible temp, quasars are apparently > 10 trillion Kelvin (10,000,000,000,000K), yet all life we know of is between what, 250K and 400K?

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Basically it's because the relevant structures are somewhat fragile. Matt Strassler has a good post about "why does everything we care about move so slowly compared to the cosmic speed limit?" (https://profmattstrassler.com/2024/10/03/why-is-the-speed-of...), and the answer is, it's because we're made of atoms, atoms are held together by the electromagenetic force, and that's only so strong, if things moved way faster then collisions would tear atoms apart. But of course life is dependent not only on atoms, but also on electromagnetic bonds much weaker than the ones that hold atoms together. So this limits how hot it can get.

If you’ll excuse a bit of trivia: SI units named after people are not capitalized. So we have newton, joule, weber, kelvin, named after Newton, Joule, Weber, and Kelvin. (But their abbreviations are capitalized: N, J, Wb, K.)

Correct. The parent of your post should have written "10 trillion kelvins", "10 terakelvins", or "10 TK". The article wrote "Temperatures there reach an astonishing 30,000-50,000 kelvin" instead of "kelvins" (or better yet, 30–50 kK).

Very few people use the unit kelvin correctly. ( https://www.reddit.com/r/Metric/comments/126sniq/everyone_mi... )

The only exception regarding capitalization is that the person Celsius is capitalized in the multi-word unit "degree(s) Celsius", and the pluralization is on "degree".

Good point about pluralization. I tend to be confused about that because we don't pluralize units in Norwegian (except the equivalent of degrees). But confusingly, in English, you sometimes see people trying to pluralize the abbreviations, such as kgs for kilograms. Or (even worse) ms for meters. That way madness lies.

"You aren't really famous in math or science until people stop capitalizing your name"

Joke I heard in the math department.

0 Kelvin is theoretical lowest possible temp

Let me introduce you to negative temperature systems!

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

Negative temperatures are hotter than positive temperatures, though, so this isn't really relevant to the parent comment.

I was aware of this, but you putting it into numerical terms rather than an intuitive understanding is really cool. Even a small fire is dramatically hotter than life, yet nothing in comparison to what happens outside of our relatively frozen little bubble here on Earth

We're also interestingly enough at around the geometric mean between atoms and stars! (as in the scale of humans)

Well, lifeforms on earth are all pretty dependent on being water based, and water in the liquid state specifically. Maybe there is a possibility of exotic life based on some other types of chemistry and/or phases of matter. But the fact that earth happened to form in this particular goldilocks zone for water-based life is probably why that's the only life we can see for now.

I have to mention Robert L. Forward’s Dragon Egg—it explores life on a white dwarf with nuclear reactions instead of chemical ones. Not the best book, IMHO, but a fun thought to entertain.

Well unless there's some ghost-like life form in a gas state, we sort of need the molecules to stay together to form life.

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