What is the Big Bang in Wolfram Physics?

There’s a straightforward answer to that question.

*Here’s* the Big Bang:

It’s what I’ve been showing you all along.

If it doesn’t *look* much like the Big Bang, that’s because I’ve been drawing the hypergraph the same size at every step. That makes it easier to see what’s happening in the earlier steps.

But if, instead, I draw the *edges* the same size at every step, you can clearly see the expansion of space:

After all, the nodes and edges of the hypergraph *are* space. In this universe, the numbers of nodes and edges increase at every step, which means that space itself *expands* at every step.

So what is the Big Bang in Wolfram Physics?

It’s the point in the evolution of the universe where the hypergraph goes from nothing to something.

It’s the start of the explosion that eventually yields the uncountable particles, planets, stars and galaxies of our universe.

So that’s pretty straightforward, isn’t it?

Well, yes, except that there’s one phrase above that demands further explanation: *nothing to something*.

How does the universe go from *nothing* to *something*?

## Nothing comes from nothing

Let’s take a closer look at that universe above.

How did it go from nothing to something?

Well, the truth is, it *didn’t*.

I generated that universe using this rule:

It’s one I’ve used many times before.

To apply the rule, we find two edges from the same node, delete one of the edges, then create three new edges to a new node.

Let me repeat that first step: to apply the rule, we find two edges from the same node.

Which means that if we *can’t* find two edges from the same node, then we *can’t* apply the rule.

That’s why, when I simulated this universe, I *didn’t* start from nothing. Instead, I started with a hypergraph of three nodes and two edges. And not just *any* two edges: two edges from the same node.

This isn’t just any old hypergraph. It’s a hypergraph that’s *designed* to allow this particular rule to be applied.

And this universe doesn’t come from *nothing*.

It comes from that carefully-designed hypergraph.

It comes from *something*.

## Dead universes

What would happen if we applied that rule to a hypergraph that’s *not* so carefully designed?

Let’s see what happens when we start with a simpler hypergraph, with just two nodes and one edge between them:

Remember, to apply our rule, we find two edges from the same node.

OK, so let’s find two edges from the same node.

Well, we *can’t*.

There *aren’t* two edges from the same node.

In fact, there aren’t two edges at all. There’s only one edge.

We *can’t* apply our rule to this simpler hypergraph.

What happens when we try?

Nothing.

This is a dead universe.

## Empty universes

Let’s go one step further.

Let’s start with an even simpler hypergraph, with *no* nodes and *no* edges:

Again, we can’t find two edges from the same node, because there *are* no edges and there *are* no nodes.

What happens when we apply our rule to this even simpler hypergraph?

Again, nothing.

This empty universe stays empty.

## Let there be light

It looks like we need to start with a carefully-designed hypergraph if this rule is to give rise to a universe that’s not dead.

It’s tempting to conclude that nothing comes from nothing.

But that’s just *this* rule:

For sure, a rule that matches two edges from the same node can’t create something out of nothing.

But maybe a *different* rule *can*.

What would a rule that creates something out of nothing look like?

Well, how about this:

To apply *this* rule, we don’t need to find *any* edges, we just create a new edge between two new nodes.

*This* rule *can* be applied to an empty universe:

to create a non-empty universe:

I know what you’re thinking. A rule that doesn’t match *any* edges? Isn’t that *cheating*?

Well, you probably didn’t object to the rule I showed you above, the one that matches *two* edges:

And you probably wouldn’t object to the rules that match *one* edge:

or *three* edges:

So if a rule can match *three* edges, or *two* edges, or *one* edge, then why not *zero* edges?

A rule that matches zero edges *does* create something out of nothing.

## Towards the ruliad

It’s true that our something-from-nothing rule doesn’t create a very interesting universe.

Apply it once, and it creates one new edge:

Apply it many times, and it creates many new edges:

These edges are completely disconnected. Each is, in effect, its own, separate, lonely universe.

But what if we were able to apply *one* rule to create something *simple* from nothing, then *another* rule to turn that something *simple* into something *complex*?

For example, what if we were able to apply *this* rule to create two edges from the same node:

then *this* rule to evolve those two edges from the same node into a complex universe?

In future articles, I’ll be exploring the possibility that we might apply *more than one rule* to the universe, indeed, the possibility that we might apply *all possible rules* to the universe.

This will take us towards one of the most fascinating constructs in Wolfram Physics: the *ruliad*.

## A deeper question

And while we’re on the subject of the Big Bang, I’ll mention one more possibility.

I’ve shown you how the rules of Wolfram Physics might create something from nothing, and how that might be the start of the explosion that eventually yields the uncountable particles, planets, stars and galaxies of our universe.

In other words, I’ve shown you how Wolfram Physics might address the question:

*How* did the universe come to exist?

But there’s a deeper question about the existence of the universe.

It’s a question that has long been thought to be purely philosophical, beyond the scope of physics.

Astonishingly, it’s a question that Stephen Wolfram believes he might be able to answer.

In future articles, I’ll show you how Wolfram Physics might address this deepest of questions:

*Why* does the universe exist?