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points by robotresearcher 3 days ago | 0 comments
The average temperature of a rock, car, or the ISS in low earth orbit is about -18C.
[–] Sammi 3 days ago
It's this huge misconception that space is super cold. A better mind model is that space doesn't have much of a temperature at all just cause there's nothing there. Vacuum doesn't have a temperature.

You won't immediately freeze if you enter space without a suit. You'll die almost immediately, but it will be because your blood will begin to boil because of the lack of pressure kinda like an extreme form of divers sickness - it's just not the cold that'll get you first.

[–] robotresearcher 2 days ago
That’s all true. But stuff in space has a temperature, and once I’d been dead a while in LEO, mine would be -18C.
[–] overfeed 2 days ago
> mine would be -18C

FYI; that's not how it works, you and the rock you mentioned in an earlier comment cannot have the same temperature of -18C. This is due to differences in material, and geometry to a lesser extent.

Even if you were rock-shaped, the rates of energy absorption and radiation is what determines your remains' temperature, this ratio differs for different materials, and thus difference fiilnal temperatures.

[–] robotresearcher 2 days ago
Sure it varies a bit. ISS average skin temp is 10C, for example.

The total available energy from the sun in LEO averages about 1.36KW/m^2, and more than this is radiated away by current deployed technology.

[–] overfeed 2 days ago
> Sure it varies a bit

No, not just a bit. It varies by hundreds of degrees depending on the materials α/ε ratio.

Your mental model is off: materials that good absorbers but poor emitters will get very hot, and the flip-side stay cool, and are used to make the cooling elements in the ISS . The temperature of ball of black nickel at 1 AU will settle at balmy 239C - not -18C. Polished Aluminum -> roughly 145C.

[–] robotresearcher 2 days ago
I’ve made a note not to make my space data center a black nickel sphere, and instead to make it like we generally make satellites.

My nickel guy is gonna be so disappointed.

I do understand the correction, so thank you. Doesn’t change my point at all, and I fear we are talking past each other so I’ll call it a day.