Question: Since you said that super conuctors are colder than space, what is the temperature in space?

Nathan Langford answered on 26 Jun 2012:

Hi all,

Yep, Harriet is right… Space is a few degrees above absolute zero temperature (0 Kelvin or -273 degrees Celcius).

Absolute zero temperature is a weird concept though… how do you understand that? Well, it turns out that what we normally think of as temperature is actually heat flow… In other words, when we touch something that we think is hot, it means that lots of heat is flowing from it into us, and when we touch something that we think is cold, it means that lots of heat is flowing from us into it. So the temperature of an object is actually a measure of the total amount of heat or energy that is stored in an object. Absolute zero temperature is therefore the temperature where there is no more energy or heat left in an object. (Well, quantum mechanics has something else to say about this, it turns out, but that’s good enough for the moment.)

No energy means nothing is vibrating, nothing is moving, there is no light radiation – nothing!

In space, there is quite a lot of light floating around, some visible and much more in other regions of the spectrum, such as the UV, infrared or microwave range. The 2.7 Kelvin temperature comes from something called the microwave background and is always there, even if you go somewhere which is far away from any suns, so there is no visible, UV or infrared light around. It turns out that the “microwave background” is something that comes all the way directly from the big bang itself!!

Cheers,
Nathan.