– Space is a vacuum with zero atmosphere, so heat does not transfer well. Could we get really close to the sun because of that?

33 views

– Space is a vacuum with zero atmosphere, so heat does not transfer well. Could we get really close to the sun because of that?

In: 4

No because of the massive amount of heat energy it expels through radiation. Radiation in the same way a big campfire makes you warm despite being a large distance from it. The same solar radiation that warms you up on a sunny day.

While there may not be conduction or convection in space, there is still radiation. And without the atmosphere filtering out a good portion of that, anything with an unobstructed view of the sun gets incredibly hot. Anything out there has to have some sort of heat shield for when facing the sun.

Yes, if there was a barrier or multiple barriers in between. The “dark” side of the barrier would remain close to absolute 0.

There are different types of heat transfers. What you are talking about is convection which does require a material to propagate. However a lot of heat transfer is done through radiation. This is why a fire feels much hotter on one side of your body then the other. The heat from the Sun is also in the form of radiation. When you get closer to the Sun the radiation becomes stronger so you heat up more.

There is no conduction of heat in space, you can only shed heat by radiation. A piece of hot metal is putting out infrared radiation; that kind of heat transfer works fine in space

The sun is blasting out TONS of heat in the form of infrared, and if you go near the sun you would absorb a lot of this radiant heat energy but going to have a very hard time expelling that heat

The Earth is heated exclusively by the sun and it gets pretty hot sometimes! (citation needed)

Thats actually not entirely true. Space acts like a vacuum on our human bodies and our spacecraft because of it’s comparatively incredibly low density, but it does have a density. Tartigrades and fungal spores can survive in space.We (humanity) actually just flew a satellite through the outer layer of the sun recently you should google it. Lots of good science there.

The planet Mercury is close-ish to the Sun (about 0.387AU, where the Earth is 1AU) and doesn’t have a horrendously thick atmosphere like Venus does. Yet it still has a surface temperature of 427C at high noon. So things still get hot even with only radiation to worry about.

The basic idea is not wrong. Put a shield between yourself and the Sun, and you’re good to go. The heat from the Sun won’t wrap around to get to you.

Examples: The Webb telescope has a shield made of multiple layers of *foil*, that has allowed it to chill down to a few degrees above absolute zero. The [Parker Solar Probe](https://en.wikipedia.org/wiki/Parker_Solar_Probe) has gotten to within ten million km from the Sun without being damaged.

There are two factors less: conduction and convection.

What you are left with is: radiation.

Your temperature is the result of what you take vs what you give away, in terms of heat.

Radiation loses strength at the square of the distance, every time you halve your distance form the sun you get four times more heat radiated onto you. Then you have to lose that heat be radiating it from you to the cosmos.

You radiate heat proportionally to your temperature difference from the outer things, let’s just assume space around you is zero kelvin in every direction to make this easy.

Let’s say, there’s a perfect distance from the sun where you get 300Kelvin degrees hot, that means 27 Celsius, quite livable.

If you cut your distance from the sun in halve you absorb four times more heat,you need to get 4 times hotter in kelvin to lose that heat and stabilize your temperature. This means you stop heating up at 1200 kelvin which is 927 Celsius which is less livable for humans.

This dumbed down a lot and not considering the full formula. The true temperature would be different from what I say for sure, but roughly, this shows you become an over cooked steak very quickly. The missing part do the formula is your color, how much you reflect of the heat, and other factors that basically are the thing we play with to shield spacecrafts from heat loss or heat takes.