How is it possible to achieve anywhere close to absolute zero if the earth is moving?

Question

I didn’t take physics past middle school so I don’t know if my understanding is correct. But my understanding is that temperature is proportional to the average kinetic energy of an object. So, since we’re zipping around the sun at 30 kilometers a second and everything on Earth must be moving at at least that speed, how is it that we can achieve within nanokelvins of absolute zero on Earth if the particle is still moving at 30 kilometers a second through space? Won’t the particle have to be completely at rest to achieve that?

In: Physics

Answer 1

Interesting thought indeed! See, temperature is defined by a speed, yes, but it’s the speed the particles wobble, and not the speed through space. Temperature is a measure of an ensemble of particles in a given space. All these thermodynamic properties like pressure volume or entropy describe an entity of particles in equilibrium. These properties become meaningless if you want to describe single particles.