Brian Greene

But at the level of the fundamental ingredients, the particles that make up the universe,

their properties.

The hope and the goal is that the theories that we work out will apply everywhere and tell us about everything.

You just said everything.

Yes.

As in everything.

Right, so there actually are a number of ways that physics comes upon this idea of other universes.

Maybe the most intuitive

is to think about the Big Bang that sent space rushing outward and matter could cool and yield to stars and galaxies, that wonderful picture that we've had with us since the 1920s.

We have, in the interim decades, come to the possibility that the Big Bang may not be a one-time event.

That is, there may have been many Big Bangs, there may continue to be Big Bang-like events, each spawning its own universe.

If that were the case, then our universe would then be viewed as one of many in this grand collection emerging from all of these events.

Big Bang-like events.

vastly different.

That's right.

So when we study the equations for the production of these universes, we see in the mathematics that the other universes could have different features, different particle compositions, different masses of the particles, different forces.

Oh, I wouldn't describe it like that at all, as you might imagine.

Rather than...

view this as an incredible loss of understanding, the right way of viewing it, I think, is to recognize that certain questions that we were asking when we thought there was just one universe were the wrong questions.

Meaning what?