As a substance’s temperature drops, the motion of its particles decreases more and more so that they become more and more tightly packed, first from a gas to a liquid, then a liquid to a solid. Simple enough. After all, heat is the kinetic energy of particles. But if you cool them enough, very strange things happen to them.
For example, take Bose-Einstein Condensates. When substances reach temperatures very, very close to absolute zero, they form a state of matter called a Bose-Einstein Condensate. Then, to quote a Nova/BBC4 program we’ve been watching in chemistry, “they have an identity crisis.” Suddenly they aren’t particles anymore. They’re waves. But at first they’re very small, individual, distinct waves. But if you keep cooling them, the waves get bigger, and they start to overlap and merge. Eventually you end up with one giant quantum state wave of, for instance, hydrogen. Just by cooling it, the particles become more wavelike even as their actual motion is decreasing.
Or take superconductors. If you drop a substance’s temperature far enough, electrical resistance in it suddenly drops dramatically, to the point where a magnet near it creates an opposite magnetic field in the substance. Why is that? Why is there a tipping point after which resistance is effectively zero?
Or to move away from cold for a moment, pulsars. A pulsar is a star spitting out electromagnetic waves in a beam, at a very specific part of the spectrum. And it’s spinning. Not like Earth’s nice, sedate 700 miles an hour. Most spin between a few times a second and once every few minutes. Stars. Spinning hundreds or thousands of times every hour. And it gets better. There are pulsars that spin as many as seven hundred times a second. And the rotation is so regular that when the radio signal was first detected for a pulsar, it was labelled “LGM” for Little Green Men.
Or switch fields again at take biology. Viruses are the ultimate parasites, literally incapable of action without a host. But they are so well adapted to their hosts that much of what we know about the more intricate parts of the immune system comes from looking at proteins viruses code for, and trying to figure out why on Earth a virus would ever make such a thing.
A lot of you probably know most of this already, but here’s my point: the universe that science has shown us is absolutely incredible, and it’s too easy to forget that. So look at what you know sometime, and take a moment to marvel in how amazing it really is.