Gas roils around inside galaxies, forming new stars; it blows out of galaxies for its own hot reasons; it hangs around outside the galaxies, cools off, and falls back in to form more stars, then blows back out again, in, out, over and over. It’s like the galaxy is breathing.

This is sheerest anthropomorphism, which is a bad word among scientists. They don’t like it – neither did my editor — because it describes in human terms, something that should be described in its own terms. Thinking anthropomorphically, you’ll probably miss what the thing – the galaxy, the virus, the moving magma – is actually, truly doing.

But it was the breathing that got me — and breathing not anthropomorphically either, not in human terms but in its own terms. So what looks like anthropomorphism, the universe described in human terms, is really humans following the rules the universe follows. One of those rules is cycles — infalls and outflows, repeat repeat — that nourish some entity through time. Until sooner or later, somehow or other, the gas leaves the galaxy and doesn’t fall back in, and the stars burn up the remaining gas until it’s gone. When the galaxy can’t breathe any more, it dies.

That’s another of the universe’s rules: entities end. Humans, we’re so cosmopomorphic.