Hi all, there's something about temperature that I don't understand. My question is as follow: the way I visualize it, microscopically, temperature gives a measure of the kinectic energy of the surrounding particles. But macroscopically, temperature seems to be something that can be felt. For instance, one feels cold on a winter night; is that due to the fact that the particles that made up my body is losing its kinectic energy to the ambient particles? Another question I have is the temperature of outer space. I remember reading somewhere that the average temperature of the universe is ~3K. I take it as a statement that the temperature in outer space is around that value, does that comes from the kinectic energy of the very tiny number of gas particles in space? In other words, in 'real' vacuum where no particle existed, is it fair to say that temperature is undefined?