The Real Meaning of Real Extreme Temperatures

How hot can it get? How cold can it get? Here on earth, temperatures fluctuate wildly, but they mostly stay in the sweet spot where we can survive (Antarctica and Death Valley excluded). but in the science of measuring temperature, physicists look at the activity of atoms. There is a temperature called absolute zero, but we've never seen it and can't achieve it. We came close once, and some really weird things happened. When we take the temperature up, exploding stars are the hottest things we can think of. How can we measure them? With physics, but we don't know about any upper limit to heat, because at a certain point, measurement becomes meaningless. Beyond that, they lost me with talk about how temperature may be a loop of some kind.    

Space Explainer takes us through temperature extremes on earth and elsewhere, narrated by cartoon paper doll scientists on cartoon popsicle sticks, for some reason. (via Laughing Squid)