# How does “temperature” work in vacuum? [duplicate]

To conduct heat, a medium is required (e.g. Atmosphere)

But at higher altitudes atmosphere is too thin, yet Wikipedia states temperatures in the thermosphere can rise to 2,000$^{\circ}$C

Electromagnetism can travel through vacuum, but is thermodynamics that simple? ISS uses radiators for thermal control, how do those "radiate" heat?

Is it just "radiation"?

• "How is the Sun's heat transmitted to Earth?" is the first question you should be asking yourself. – Andrew Thompson Mar 21 '17 at 6:52
• I think there are several questions and some good answers about this already - it might be good to do a search within SXSE. – uhoh Mar 21 '17 at 9:14
• @uhoh It would be a better idea to define entropy for him. – Raze Mar 22 '17 at 6:53
• @Raze go for it. I have so much entropy in my head that I can't wrap my mind around it. – uhoh Mar 22 '17 at 10:26
• @uhoh I am afraid there is just as much entropy in my head than as it is in your head. – Raze Mar 22 '17 at 16:36