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[-] BenderRodriguez@lemmy.world 187 points 1 week ago

Earth's atmospheric temperature is not what this person is talking about. The temperature outside your door depends on the sun, sure, but it's due to Earth's atmosphere. Go 60 miles towards "up" and the temperature of space is not the 68 degrees it is on the ground.

I think OP is questioning the temperature of the vacuum of space near the Sun. It doesn't really work like that though.

[-] arandomthought@sh.itjust.works 69 points 1 week ago

To expand on the "doesn't work like that" part: In the vacuum of space there is no air to exchange warmth with your body, or your space suit. You might be comfy on the side of your body facing the sun (if you're at that distance where it provides the right amount of radiative heat) but the side facing away from the sun will get no heat, and therefore be cold. I imagine that would feel very weird... if you could feel it on your skin, without a space suit, without being ripped apart by the vacuum, of course.

Does anyone know whether this "uneven distribution of heat energy" is a problem for space suits or if that little bit of air inside is enough to distribute it?

[-] deadbeef79000@lemmy.nz 47 points 1 week ago* (last edited 1 week ago)

NASA EVA suits have liquid (water) cooling systems to avoid cooking the astronaut while outside the ISS.

I don't know how they actually work though. The only way to shed the heat is to radiate it away or to sink it into warming something else up.

Found this on Wikipedia:

In an independent space suit, the heat is ultimately transferred to a thin sheet of ice (formed by a separate feed water source). Due to the extremely low pressure in space, the heated ice sublimates directly to water vapor, which is then vented away from the suit.

The ice sublimator consists of sintered nickel plates with microscopic pores which are sized to permit the water to freeze in the plate without damaging it. When heat needs to be removed, the ice in the pores melts and the water passes through them to form a thin sheet which sublimates. When there is no need for heat to be removed, this water refreezes, sealing the plate. The rate of sublimation of the ice is directly proportional to the amount of heat needing to be removed, so the system is self-regulating and needs no moving parts. During EVA on the Moon, this system had an outlet gas temperature of 44 °F (7 °C),[1] As an example, during the Apollo 12 commander's first EVA (of 3 hrs, 44 minutes), 4.75 lb (2.15 kg) of feedwater were sublimated, and this dissipated 894.4 BTU/h (262.1 W).[2] The pores eventually get clogged through contamination and the plates need to be replaced.[3]

Though I think that's specifically for removing the astronaut's body heat.

[-] Red_October@piefed.world 5 points 6 days ago

It's also for removing the suit systems heat, and heat from sunlight. As much as we love to say space is cold, the problem things in space have is the exact opposite. Without air for the convection or conduction of heat things in space, be they satellites, a space station, or a human in an EVA suit, have a very hard time expelling heat. The International Space Station has enormous radiators on the dark side of it's solar panels for this very reason, getting rid of heat is hard when you can't just blow air over a heat sink.

Also, for what it's worth, the average energy of what few particles there are in the vacuum of space tends to be pretty high, but they're so dispersed that it's entirely negligible.

[-] deadbeef79000@lemmy.nz 1 points 5 days ago

I always try to explain that space is cold on average but near a star it is really hot.

Case in point: the Earth. Standing on its surface under 100km of atmosphere, the sun will still burn your skin in minutes... imagine sunburn without the ozone layer.

[-] Akasazh@lemmy.world 20 points 1 week ago

What a great system. I wonder how the development of that worked. Did they theorize the necessity of a system like that or were the first space walkers quite unconfortable?

[-] Jarix@lemmy.world 27 points 1 week ago

There are glacier fed lakes when i live. You can float in incredibly cold water and if you have just the right equilibrium you can half float in freezing cold water while half getting a nice sun bath. And it IS very weird.

One spot I camped at for many years had nice sandy area that was about 200 meters out into the lake before a drop off. As it was only about a meter deep it used to warm up the top foot or so of the water when it was fairly still and you could stick your arm down into the water and actually feel the temperature drop like there was a line underneath the water.

Was great place to camp before it got overwhelmed by mosquitos

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[-] Honytawk@feddit.nl 7 points 1 week ago

What if we spin around like a spit roast so the heat gets evenly distributed?

How fast should we spin as well?

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[-] JackbyDev@programming.dev 8 points 1 week ago

You don't think a function of the temperature from the sun to the earth forms a continuous line? You think it's piecewise? It's continuous! Yeah it probably bottoms out to effectively zero pretty quick, but there's some distance from the sun that would be the right temperature. Sure, the other rays from the sun might not make it livable. Sure, it might be so narrow there's no way to effectively keep yourself in orbit there without getting sucked closer and burning up. Sure, it's a dumb thought experiment, but there's no way there isn't some point where it's comfortable.

[-] chiliedogg@lemmy.world 7 points 1 week ago

The thing about temperature is that it's not instant. Radiation from the sun heats stuff up, and that heat is absorbed by whatever the radiation hits according to its reflectivity and shape, and then lost from conduction, convection, and radiation. The characteristics of what's being heated by the sun and the environment it's in are what determine how hot it gets.

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[-] chemical_cutthroat@lemmy.world 6 points 1 week ago

I'm not a scientist, but I'm pretty sure temperature is the energy given to the molecules in the air by the radiation from the sun. Since there is no air in space to excite, it's just really cold until it's not.

[-] WalrusDragonOnABike@reddthat.com 13 points 1 week ago

The photons would directly excite the molecules in your body.

[-] dfyx@lemmy.helios42.de 13 points 1 week ago* (last edited 1 week ago)

Which is why space suits are white. If they were darker, you‘d get cooked on a space walk. In a vacuum, the sunlight can heat you up but it’s much harder to radiate heat away.

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[-] Fleur_@aussie.zone 36 points 1 week ago

I've heard that basically everywhere you go in space you will die by overheating because your body can't radiate away the heat it generates. It's weird to think that you can die from literally being cooked alive in a vacuum with a temperature of 0 degrees (readers choice of units).

Temperature is one of the least intuitive things when really getting into the nitty gritty of it. One of my favorite things to prompt people with is to ask them what makes something twice as hot as something else?

[-] jerkface@lemmy.ca 6 points 6 days ago

It's exactly like being trapped in a thermos. But! There are space suit concepts that use an airtight helmet, but the rest of the body effectively is exposed to vacuum, supported and protected using a skin tight water-permeable fabric that prevents you from swelling up or burning in the UV. One of the benefits of this kind of space suit is that SWEATING WORKS IN SPACE!!! The sweat carries away heat (and further consumes it in the phase transition) when it instantly flashes to vapor, cooling one's body. Sweating is a human super power and we can leverage it to perform our own temperature regulation in a vacuum! I've always thought that was super cool.

[-] Fleur_@aussie.zone 1 points 6 days ago

That is super cool!

[-] Smoogs@lemmy.world 1 points 5 days ago

and then there is the wet light bulb situation where your body can just suffocate as it sweats and cant evaporate.

We’re basically just porous critters. Just assume we need to breath from everywhere on the body.

[-] echodot@feddit.uk 15 points 1 week ago

Temperature is the average speed of atoms, in space, what atoms?

Space isn't cold. It just isn't any temperature

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[-] GhostedIC@sh.itjust.works 8 points 1 week ago

Rather than reader's choice of units, it has to be Kelvin... 0F or 0C is warm in absolute terms.

[-] Lifter@discuss.tchncs.de 5 points 6 days ago

Also, Kelvin doesn't have degrees.

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[-] DickFiasco@sh.itjust.works 21 points 1 week ago

Instead of wasting our resources trying to terraform Mars, we should look for planets already in this "balmy zone" to live on.

[-] zaphod@sopuli.xyz 45 points 1 week ago

You mean like not fucking up the planet we live on? That's impossible, you're insane.

[-] Arsecroft@lemmy.sdf.org 12 points 1 week ago

¡terraform earth!

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[-] Bronzebeard@lemmy.zip 11 points 1 week ago

We've had one planet, yes. But what about second planet?

"I don't think he knows about second planet, Pippin."

[-] tomiant@piefed.social 6 points 1 week ago

Here's an idea, let's clean up our home.

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[-] tomiant@piefed.social 16 points 1 week ago

Space has no temperature. Space is a vacuum. Temperature needs things to jiggle.

[-] salvaria@lemmy.blahaj.zone 14 points 1 week ago

The average temperature of the universe today is approximately 2.73 K (−270.42 °C; −454.76 °F), based on measurements of cosmic microwave background radiation.

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

Cited from https://www.abc.net.au/science/articles/2003/09/25/947116.htm