That oughta bring ’em in.

It’s true, though. You’re at a wildly unusual temperature compared to the rest of the universe. You’re so hot, in fact, that you’re constantly giving off light. True, it’s light your eyes aren’t adapted to see, but nonetheless you are a gleaming beacon of hotness in a mostly cold universe.

I was talking with some colleagues about liquid nitrogen today. Liquid nitrogen seems like weird stuff. If I were to submerge my hand in liquid nitrogen, I would suffer major and permanent damage. But the damage isn’t because liquid nitrogen is so abnormally cold. It’s because my hand is so abnormally hot. Were I foolish enough to plunge my hand into liquid nitrogen, an enormous amount of heat would leave my hand in order to warm the nearby nitrogen. The result is quickly boiling nitrogen – and a dead hand.

Think how strange that is! When you touch an unusually hot object, the atoms of that unusually hot object move quite quickly, colliding with your atoms and causing them to move quite quickly, as well – probably boiling the water in your cells and giving you a nasty burn.

Now consider touching something at around the same temperature as you – maybe your favorite teddy bear. In this case, the atoms in your hand and the atoms in the bear are pounding on one another with essentially the same force. No harm, no foul.

Finally, think about liquid nitrogen. It’s like reaching for a rung on a ladder that isn’t there. Your hand’s energy pushes, but the nitrogen barely pushes back at all. The extra movement from your hot hand goes into giving the nitrogen molecules that extra movement they need to escape as gas, and your hand gets a whole lot colder.

In fact, liquid nitrogen itself isn’t all that cold, compared to the universe at large. Next to the chill of isolated deep space, liquid nitrogen is chock full of heat energy. Even solid nitrogen is full of heat energy, until it gets down to around 3 kelvins, the current background temperature of space. Things we generally think of as exceedingly cold – liquid nitrogen, a block of ice from the antarctic, and that slufreezy you purchased at the gas station on the way home that gave you brain freeze – all of these are so full of heat energy that they, too, glow with invisible light, light just a little less energetic than the light coming from you. The reason you think of these things as cold is because you, my friend, are so fantastically HOT!

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