Electron Temperature Gradient...?

Question

Okay. This question pretains to temperature of atoms and subatomic particles.

As I understand it, thermal energy comes from the random motion of atoms in an object. I'm perfectly willing to accept this. However, what if we have a single atom?

Furthermore, I saw a title for a paper at www.arXiv.org that had "the Electron Temperature Gradient of the Milky Way" in it. That got me wondering, can subatomic particles, such as electrons, have temperatures? If so how? If not, why?

Answer 1

Temperature is just the measure of the random movement of a particle or another way to say it is the amount of kinetic energy the particle has. When cosmologists talk about microwave background radiation or temperature of the milky way all they are saying is the temperature they measured from whatever they surveyed by collecting in the microwaves or light waves from the source. If we collect microwaves, we know the temperature the atom had when it sent it away. same for light. Remember the star diagram we see in high school where they show different stars with different colors? The color represents certain temperatures. We can measure the temperature of atoms the same way by collecting and analyzing the wavelength it sends out. The atom releases waves when the electron transitions from higher orbit to a lower orbit. How the electron got to higher orbit is when it collides with another atom or sub particle. So in a way, electrons and sub particles can transfer kinetic energy to another atom when they collide and we can measure the temperature by measuring the wave we get. I think it's meaningless to talk about the temperature of a single particle, but for continuous distribution of atoms, temperature can be discussed

Answer 2

If you only had one atom, then it would have to be in a vacuum, because otherwise you'd have its reaction with the other atoms around it. So I guess a single atom wouldn't actually have a temperature.