Hit me with some space knowledge

[cbrunny]

I have a Hydro Flask thermos. It's friggin amazing. Keeps my coffee hot all day I think by surrounding the inner cylinder with an outer cylinder, and between the two cylinders (where the insulation would go) is a vacuum. I think that's how it works, and I think that's very cool.

But I remember Padme saying to that wiener Anakin that space is very cold. I guess I can see how that would be true, if by cold she means there aren't a lot of atoms capable of transferring heat via conductive and convective methods. Does "space" have a temperature?

Isn't the extension of that having space ships/ISS (in real life) that are forced to dump heat into space (somehow)? That is, if heat can't escape the interior shuttles because it can't conduce or convect out.... wouldn't it just increase until the internal temps were the same temp as the source of the heat?

I don't understand. I am obviously wrong. But what is correct?

 

[deadlyapp]

There is only radiation in space, so for ISS, you end up having a very hot side (facing the sun) and then a very cold side that is shaded. For ISS it can balance its heat load by using those two surfaces.

Space itself has no temperature, but anything in space does have a temperature.

This is a fun article.
http://www.universetoday.com/77070/how-cold-is-space/

Doesn't really get into the very physics side of it but does discuss a bit.

 

[dave_the_nerd]

No, pretty much everything you just said is correct.

In a vacuum, there's nothing physical to transfer heat. That's why the mug stays warm - the heat has nowhere to go and no way to get there.

But that's not an absolute - there is still some ability to radiate heat in a vacuum, as infrared radiation, just not nearly as quickly. (That's how the sun's heat gets to us.)

http://helios.gsfc.nasa.gov/qa_sp_ht.html

Which is why spacecraft use big old liquid cooled heatsinks:

https://www.nasa.gov/mission_pages/station/structure/elements/radiators.html
https://www.nasa.gov/pdf/473486main_iss_atcs_overview.pdf

 

[cbrunny]

So the ISS absorbs radiant heat, and gives off radiant heat? and that's how it balances it's temps? Interesting!

 

[dave_the_nerd]

So the ISS absorbs radiant heat, and gives off radiant heat? and that's how it balances it's temps? Interesting!

That's pretty much true of everything. Lie naked in the sun during the day, your dick absorbs radiant heat. Wave it in somebody's face after sundown, and you're giving off radiant heat. Just not enough to glow. Which would be very, very bad.

 

[Tim]

So in a vacuum, how does stealing threads from reddit and posting them here transfer heat? I suppose we will never know...

https://www.reddit.com/r/askscience...does_heat_propagate_in_a_vacuum_if_there_are/

 

[Red Squirrel]

There are special radiators on the ISS that shed the heat.

Liquid ammonia flows there those and sheds the heat as IR. ... and looks like someone is going to be doing a space walk to go fix that one.

 

[dave_the_nerd]

So in a vacuum, how does stealing threads from reddit and posting them here transfer heat? I suppose we will never know...

https://www.reddit.com/r/askscience...does_heat_propagate_in_a_vacuum_if_there_are/

Meh.

I googled a bunch of this stuff a few months ago because I got into playing KSP again. Coincidences happen.

 

[Tim]

Indeed they do. I guess I just couldn't stop myself from going there.

 

[shortylickens]

space is cold in the sense of exposure. particles and energy can fly off your body without being trapped. whereas even cold atmosphere provides SOME energy.


Fun fact: Snow is an excellent insulator. Like water-based fiberglass rolls.

 

[cbrunny]

No lie. I've never been on reddit. I don't even know what the home page looks like.

 

[Charmonium]

But . . . but . . . the microwave background is only about 4.7 Kelvin. That's damn near absolute zero.

 

[Red Squirrel]

Some people now figure you can go negative kelvin. Not sure how that would work as 0k is when everything comes to a stop. I always figured zero kelvin was theoretical and that you can't actually get there and just close, and you can always get closer but never to it. Physics can get weird when you get into the more complex stuff though.

 

[Darwin333]

On the moon doesn't the temp go from like +200 to -200 if you walk into a shadow like a crater or behind a hill?

 

[MrSquished]

your thermos is from the future

 

[dave_the_nerd]

On the moon doesn't the temp go from like +200 to -200 if you walk into a shadow like a crater or behind a hill?

yes.

 

[Red Squirrel]

That's kinda mind boggling but it does make sense if there's no air to keep heat and no atmosphere to deflect lot of the sun's energy.

Could be interesting for building habitats though, you could have radiators in various parts, some shaded some not and basically get the exact climate you want inside of the pressurized domes. I guess that's probably what they do on the ISS. They probably don't have heaters or AC just circulating liquid.

 

[Carson Dyle]

In space, no one can hear you scream.

 

[slugg]

Fun fact: in space, nobody can hear a tree fall, so it's impossible for a tree to fall.

 

[Murloc]

That's kinda mind boggling but it does make sense if there's no air to keep heat and no atmosphere to deflect lot of the sun's energy.

Could be interesting for building habitats though, you could have radiators in various parts, some shaded some not and basically get the exact climate you want inside of the pressurized domes. I guess that's probably what they do on the ISS. They probably don't have heaters or AC just circulating liquid.

could be interesting for power generation, although I wonder if a complex mechanical system would be better than solar panels to power a moon base, in space solid state just seems a better idea. Cold liquid goes down, gets vaporized, flows up through a turbine and to the dark side and goes back down.

Still, with a pump and a hydraulic circuit you can power the climatization system for free since you can just get or lose heat so easily. That must be useful given how much power that stuff uses.

Some people now figure you can go negative kelvin. Not sure how that would work as 0k is when everything comes to a stop. I always figured zero kelvin was theoretical and that you can't actually get there and just close, and you can always get closer but never to it. Physics can get weird when you get into the more complex stuff though.

My guess is that they're not reasoning in classical mechanics terms but it's weird modern physics stuff, where the model of the little balls being completely still has long stopped making sense.

 

[IronWing]

On the moon doesn't the temp go from like +200 to -200 if you walk into a shadow like a crater or behind a hill?

Looks like a moon colony could meet all its energy needs through well placed sterling engines.

Fun fact: in space, nobody can hear a tree fall, so it's impossible for a tree to fall.

Free fall tree fall?

 

[sdifox]

Fun fact: in space, nobody can hear a tree fall, so it's impossible for a tree to fall.

First you need to move a tree into space.

 

[cbrunny]

Then you need to decide which direction = fall.

 

[IronWing]

First you need to move a tree into space.

A pine tree would be best. We could just use a nose cone.

 

[cbrunny]

this..... this is a strange thread...