If you missed it yesterday, here’s the TED video which started this line of thinking.

I’m toying with Wolfram’s idea of computational space in relation to the theory of universal evolution—which unfortunately is not covered under this name in Wikipedia. The theory, as I remember it, is that as black holes can theoretically spawn new universes in separate spacetimes, that each new universe would experience a slightly different set of laws of physics from its parent universe. Therefore, our own universe is the result of several million or billion generations of prior universes. This neatly answers the anthropomorphic fallacy, i.e., “why are the laws of physics suitable for the development of life?”, by stating that a universe with the basic requirements for humans was not only impossible earlier in universal evolution, but that it was also pretty much inevitable.

I’m fond of this theory, in that any time an impossible occurrence reaches a probability of 99.999%, there’s a certain beauty to the idea. Wolfram takes it a step further, though: just as a non-Euclidian geometry allows for all sorts of mathematics which can never apply to our universe, his computational theory allows for an infinite set of universes which is of a higher order than the infinity supposed by evolution. Evolutionary universes can be infinitely branching, but can never supercede certain starting states: for example, many of them may not have the conditions necessary to create hydrogen, but all of them may have to have the same basic subatomic particles in order to create hydrogen.

Or not. Maybe there’s an alternate path to matter. Just as the laws of physics dictate what’s possible in our universe, when you’re considering the range of theoretically possible sets of all such laws, then you’re operating from a deeper substrate than I think we can yet describe with science. (Or at least, any science I’m familiar with.) Wolfram’s method does away with “possible” as being a necessary concern; if his universes are mathematically consistent, then they can exist as models even if there’s no possible method that such a universe could ever actually occur.

In any case, the core thought that I keep coming back to with these kinds of ideas is this: not only does the universe appear to be infinite, but the methods in which it is infinite may be as well.

For example: the edge of the visible universe is precisely 13.7 billion light-years away from us in all directions. Why? Because that’s the farthest light can travel during the age of the universe. However, the universe is known to be larger; we can see the effects of the invisible universe on the edges of the visible, so we can tell, for example, that there’s an invisible body of N solar masses on the other side of a boundary which we can never cross. This is because while things within space are limited by light speed, space itself is not. The universe could have expanded at any speed—we know it was at least the speed of light, but it could have been faster, and it could have been infinite. (Note: space does not mean “outer space”. It’s more accurate to think of “space” as a four-dimensional mathematical grid in which the universe is housed; that’s the space which can expand at any speed.)

In case you haven’t stopped to think about the word “infinite”, a reminder: assuming the same distribution of physical materials throughout, then the number of yous who are reading this post, and the number of mes who wrote it, are also infinite. 1/10^-100 * infinity = infinity. For this reason, I tend to believe that while the universe is mind-bogglingly huge—the visible universe may only be a tiny fraction of the whole of it—I think it’s likely to be sub-infinite. But not necessarily.

In the meantime, there’s also the many-world theory, which basically states: quantum physics is really strange, and things happen in terms of probability, but the word “happen” is a lot fuzzier than we’re used to. The math works out that when a particle is observed, it’s possible that all sorts of other things the particle is simultaneously doing just cease to exist—or it’s possible that all of those other things just go off and take place in other universes.

Usually when this is stated in science fiction, it’s said that, “Since you could have had coffee or tea this morning, one of you had coffee, and one of you had tea.” But this is more accurately happening at the level of the Brownian motion of the water while it’s still in the kettle. There are 10⁸⁰ atoms in the universe, give or take, each made up of a menagerie of particles which we still can’t count. Every 1/10³⁴ seconds, all of the stuff making up all of those atoms do things, and the things they don’t do might be spawning exact copies of the universe, except for what they’re not doing. So that’s 10⁸⁰ atoms * 10^??? particles * 10³⁴ Planck timelengths per second * 4.32 * 10¹⁷ seconds since we all got here.

Yeah, that’s how big it all is. The age of the universe in seconds is the smallest number in the equation.

And each one of those universes goes on to do the same thing we’re doing, so every Planck time, you’re not duplicating the universe that many times; you’re multiplying by that number. Create 10¹⁰⁰ universes the first second, and you’ll create 10^10,000 the next. Except where I wrote 10,000, you really need to add a hell of a lot more zeroes. That’s not infinite—you don’t reach infinity with multiplication of finite numbers—but it’s still a lot of elbow room.

But there are still two rules bounding this entire thing: first, that it all starts with the Big Bang, and second, that all of these universes will suffer heat death. It’s all temporally finite, regardless of what else it is.

Which brings me back to universal evolution. Heat death makes no sense to me: a temporally finite universe is one in which only a limited number of things can happen. A temporally finite multiverse, such as the one described above, is sufficiently vast that everything that can happen within it does happen, somewhere, so long as it doesn’t break any physical laws. But then it all dies.

That doesn’t make much sense. It puts us back in the category of being infinitely lucky, since of all of Wolfram’s possible universes, in most of them there’s no matter and no life. You need one variable of infinite scope to make us inevitable—time seems to work, and spawning new baby universes in addition to the multiversal spawning listed above gives us both the infinite vector, as well as the guarantee that any universe which is created also sees every possible outcome of itself play out.

So our universe goes on through its multiversal existence, and spawns a few trillion trillion other universes in the process, which suddenly makes its own heat death… worthwhile? Don’t know what you’d call it, exactly. But at the very least you can call its existence a mathematical near-certainty.

Anyway… honestly, this really is how I think the universe works. Because it fits. Humanity spent over 200,000 years believing that the Earth was a few thousand years old, and then found out that our existence required both a really big planet and a really long time. And even then, if the solar system hadn’t whacked us a bunch of times with really big rocks, we’d still be dodging dinosaurs and the size of field mice today. (So I’d add a third component: it also needed a nearly infinite number of Earths. In our neighborhood, we’re at the top of the food chain. Elsewhere, we’re still field mice.)

We also found out that the 4.5 billion years or so that Earth had is only a third of how long the universe has been around. It took 500 million years for the first stars to form, and it took two more generations of stars going boom and reforming before they created elements that we find useful, like carbon, oxygen, and iron. In 100 years, we’ve gone from mostly thinking that the Milky Way was the universe, to knowing that there are more galaxies than the Milky Way has stars. (That we can see—there might be more. Cf. visible universe above.)

So that’s two cases in which the canvas is a hell of a lot larger than the artwork. All I’m saying is that we’re being awfully limited in assuming that’s all the canvas there is. It’s the nature of being human: we don’t have eyes that can see X-rays, so they didn’t exist for us until the Curies came along. Light was a much wider canvas than we thought.

Seems to me, since the universe is always wider than we thought, well, it makes sense to start expecting it in places where we don’t yet know how to look.