I thought space was WAY colder than that

winnipeg marsSo you may have heard the recent news story that on January 1st, 2014, Canada’s own city of Winnipeg, Manitoba, was actually colder than Mars.

(by the way, Winnipeg is actually further south than depicted in that image, it’s pretty close to the Minnesota border, not an arctic circle city – just FYI)

I saw this and I was like “buh?”.

See, I would imagine I’m not the only one who’s thinking “wait, isn’t space like super freezing? Like if astronauts take off their helmet in space, they’d be instantly flash frozen into a meaty human popsickle?”

This is what I had thought, but apparently this isn’t quite correct. Or at least, there’s more to the story.

I know that Mars doesn’t have an atmosphere, and I had thought that a large part of what keeps Earth from descending into a permanent ice age, is the greenhouse effect. But I guess I was wrong, so I decided to do some digging to find out what’s actually the case.

I decided to google “how cold is space”, and already I’ve learned something that made me go “huh”. From UniverseToday:

Unlike your house, car, or swimming pool, the vacuum of space has no temperature.

So, how cold is space? That’s a nonsense question. It’s only when you put a thing in space, like a rock, or an astronaut, that you can measure temperature.

Remember there are three ways that heat can transfer: conduction, convection and radiation. Heat up one side of a metal bar, and the other side will get hot too; that’s conduction. Circulating air can transfer heat from one side of the room to another; that’s convection. But out in the vacuum of space, the only way heat can transfer is radiation.

Photons of energy get absorbed by an object, warming it up. At the same time, photons are radiating away. If the object is absorbing more photons than it emits, it heats up. And if it emits more photons than it absorbs, it cools down.

There is a theoretical point at which you can’t extract any more energy from an object, this minimum possible temperature is absolute zero. As we’ll see in a second, you can never get there.

So the error I had made, is that space itself has an inherent temperature. That is not the case. In retrospect, it makes sense, since sound can’t travel in a vacuum, it also stands to reason that in the absence of air (ie in the vacuum of space), there is nothing to hold or move heat.

What this tells me is that the surface of mars likely relies on radiation for heat (I don’t think the thin atmosphere there allows for convection, nor is there any volcanic activity that I’ve heard of), and the only radiation it’s getting is from the Sun, like us. It’s further away, but close enough I guess to still be equivalent to some of the more arctic temperatures on Earth.

Let’s look close to home, in orbit around the planet, at the International Space Station.

A piece of bare metal in space, under constant sunlight can get as hot as two-hundred-sixty (260) degrees Celsius. This is dangerous to astronauts who have to work outside the station. If they need to handle bare metal, they wrap it in special coatings or blankets to protect themselves. And yet, in the shade, an object will cool down to below -100 degrees Celsius.

Astronauts can experience vast differences in temperature between the side facing the Sun, and the side in shadow. Their spacesuits compensate for this using heaters and cooling systems.

Let’s talk a little further out. As you travel away from the Sun, the temperature of an object in space plummets. The surface temperature of Pluto can get as low as -240 Celsius, just 33 degrees above absolute zero.

See, that explains why I thought what I thought. In the shade, in space, things are VERY cold. And if you were an astronaut, in the shade of Earth, and you took off your helmet, you probably would flash freeze.

The other interesting point is that we’ve only had the Discovery rover on Mars for a little while. I believe that is where the temperature reading came from. That means, for all I know, we’ve been colder here on Earth than the surface of Mars plenty of times, but we just didn’t know it. And I’m guessing the rover was in the sunlight when this measurement was taken, otherwise I would expect it to have been much colder.

Still, pretty mind boggling. And to think, human beings not only choose to live in Winnipeg, but even further north where it’s even colder! If we could set up an atmosphere on Mars, we could probably actually make it rather decent living conditions wise.

2 thoughts on “I thought space was WAY colder than that

  1. plushduckie

    This is a great line of questioning! Thanks for pursuing that! And I can’t be quoted on this, but I think some conduction happens within the planet’s core as well. The thing with large masses held together by their own gravitational field is, there’s an awful lot of pressure built up by the time you get to the core! And naturally, this pressure creates a lot of heat, which mostly dissipates by the time it reaches the planet’s surface. But I often wonder if there isn’t a good way to channel that internal pressure into energy and heat, which could eventually be phenomenal, consistent power and heat for space explorations. 😀 I know there’s something already in use, but I can’t for the life of me remember what it’s called! Some kind of “natural heating solution” that you find occasionally in modern homes. And also, I do realize how ridiculously huge, and thick our planet’s crust is, and we’re nowhere near penetrating that, but maybe we don’t have to go that far!
    Some more to think about. :p


    1. AdamEmanon

      I believe what you are referring to is “geothermal” power 🙂 I don’t even think there is only 1 kind of it, I think there are a few. One that I’m aware of involves running pipes down deep into the ground to where it’s closer to the core and hotter, and then pumping water through the pipes which gets heated and then comes back up. Sort of like a natural hot water heater.


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