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xkcd #2972: Helium Synthesis (xkcd.com)

submitted 1 month ago by [email protected] to c/[email protected]

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Our lawyers were worried because it turns out the company inherits its debt from the parent universe, but luckily cosmic inflation reduced it to nearly zero.

https://explainxkcd.com/2972/

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[–] [email protected] 4 points 1 month ago (2 children)

For cooling purposes, is nitrogen not as good?

[–] [email protected] 9 points 1 month ago

Best as I can make out, no. Current MRI tech apparently needs temperatures as low as 9 Kelvin and nitrogen freezes solid at 64. Since Kelvin units are an absolute scale, we could say that it needs to be 7 times colder than nitrogen can provide.

What I can't make out is whether nitrogen is any more dangerous than helium if it gets too warm and explosively decompresses.

Helium does have the advantage that it would escape straight up and through anything even vaguely porous, where nitrogen would just hang around displacing oxygen, causing more of a suffocation risk. How much more, again, I'm not sure.

[–] [email protected] 2 points 1 month ago

Depends? Liquid nitrogen can freeze a lot of vibrational degrees of freedom in place, but if you want molecular rotations to stop as well, there's no way around He.