Many cosmologists now think our spatial universe is infinite. That’s news. It was only this year that I heard about it. I don’t get out as much as I used to.
Thirty years ago it was widely believed that our spatial universe is the finite 3D hypersurface of a 4D hypersphere—analogous to being the finite 2D surface of a 3D sphere. Our underlying hypersphere was supposedly born, and began expanding, at the Big Bang. And eventually our hypersphere was to run out of momentum and collapse back into a Big Crunch—which might possibly serve as the seed for a new Big Bang. No yawning void of infinity, and no real necessity for a troublesome initial point in time. Our own Big Bang itself may have been seeded by a prior Big Crunch. Indeed, we could imagine an endless pearl-string of successive hyperspherical universes. A tidy theory.
But then experimental cosmologists found ways to estimate the curvature of our space, and it seems to be flat, like an endless plane, not curved like the hypersurface of a hypersphere. At most, our space might be "negatively curved," like an endless hyperbolic saddle shape, but then it’s probably infinite as well.
If you’re afraid of infinity, you might say something like this: "So, okay, maybe we’re in a vast infinite space, but it’s mostly empty. Our universe is just a finite number of galaxies rushing away from each other inside this empty infinite space—like a solitary skyrocket exploding and sending out a doomed shower of sparks." But many cosmologists say, no, there are an infinite number of galaxies in our infinite space.
Where did all those galaxies come from? The merry cosmologists deploy a slick argument involving the relativity of simultaneity and the inflationary theory of cosmic inflation—and they conclude that, in the past, there was a Big Bang explosion at every single point of our infinite space. Flaaash! An infinite space with infinitely many galaxies!
Note that I’m not talking about some shoddy "many universes" theory here. I hate those things. I’m talking about our good old planets-and-suns single universe. And they’re telling us it goes on forever in space, and on forever into the future, and it has infinitely many worlds. We aren’t ever going to see more than a few of these planets, but it’s nice to know they’re out there.
So, okay, how does this affect me in the home?
You get a sense of psychic expansion if you begin thinking in terms of an infinite universe. A feeling of freedom, and perhaps a feeling that whatever we do here does not, ultimately, matter that much. You'd do best to take this in a "relax" kind of way, rather than in an "it’s all pointless" kind of way.
Our infinite universe’s inhabited planets are like dandelion flowers in an endless meadow. Each of them is beautiful and to be cherished—especially by the little critters who live on them. We cherish our Earth because we’re part of it, even though it’s nothing special. It’s like the way you might cherish your family. It’s not unique, but it’s yours. And maybe that’s enough.
I know some of you are going to want more. Well, as far as I can see, we’re living in one of those times when cosmologists have no clear idea of what’s going on. They don’t understand the start of the cosmos, nor cosmic inflation, nor dark energy, nor dark matter. You might say they don’t know jack.
Not knowing jack is a good place to be, because it means we’re ready to discover something really cool and different. Maybe next year, maybe in ten, or maybe in twenty years. Endless free energy? Antigravity? Teleportation? Who can say. The possibilities are infinite and the future is bright.
It’s good to be an infinite world.