I was thinking about the fact that space contains all sorts of matter and that these objects have temperatures. But then I read that space itself has a temperature depending on where you are. The cosmic background radiation for example has a temperature of 2.7K. Can someone explain what that means? I assumed that temperature is just a measurement of the thermal energy of an object, whereas space is not material. I would have thought space has no temperature at all but that objects in space can be heated by whatever thermal radiation is present. Does radiation itself have a temperature?