Brian Greene Explores Multiple Universes in ‘The Hidden Reality’

Physicist Brian Greene turns his attention to the idea that our universe might be just one of many in his latest book, The Hidden Reality. How close does science fiction come to science fact? Greene addresses his theory in this short interview.

I love science, and I’m completely fascinated by the idea of multiple universes, but I’m afraid that I’m probably not smart enough to understand the science behind your book. Should I be? How accessible is The Hidden Reality for your average reader?

I wrote The Hidden Reality for the reader who is curious about cutting-edge ideas being explored in physics, but who doesn’t have background in the subject. That sounds like you. Which is not to say the book is an easy read–I take the reader through some pretty strange and wild ideas, perhaps some of the wildest that scientists have ever contemplated. But the average reader can surely grasp the essential developments.

What’s the essential premise of The Hidden Reality? Complication: Explain it to me like I’m a particularly eager but none too bright twelve year-old.

The conventional meaning of “universe” is everything, the totality of all that exists. But developments in physics from a wide variety of perspectives suggest that what we’ve long thought to be “everything” may be but a small part of a much bigger, much grander whole. And that grander expanse may contain other realms, like ours, that would rightly be called universes of their own. The whole shebang may thus contain many universes–it may be what we now call a “multiverse”. The Hidden Reality explains the chain of reasoning that has led scientists to this possibility, critically assesses why we should take the idea seriously, and explores what these other universes might be like.

How do scientists such as yourself even begin exploring an idea like this?

Keep in mind is that the possibility of other universes is not borne from wild speculation that we then seek to connect with scientific understanding. Instead, we follow the standard approach of using mathematics to describe results from experiments and observations. And then we push those equations further, to see what that math suggests about the broader conception of reality. The curious thing is that the math from a range different areas–quantum mechanics, gravity, cosmology, string theory, to name a few–lead us to the possibility of other universes. By no means does that mean the idea is correct, but it encourages us to take the possibility seriously and investigate it fully.

Some science fiction television programs and novels have featured alternate realities as plot devices. Some even have characters who travel to these realms. Would this ever be possible in the way that we currently understand the laws of physics?

No. With our current understanding, there’d be no way for us to actually travel to another universe.

Sometimes I become awe-struck by what a strange, magical place our world is. Do scientists still retain a sense of awe as they learn more about how things work? Is there ever a point at which you cease to be amazed?

I can only speak for myself, but the answer is absolutely yes. It is not like I’m in some perpetual state of awe and wonder. But even for things I’ve learned twenty or thirty years ago, like the way time slows when someone is in motion or the fact from quantum mechanics that reality is governed by probabilities–well, I find these features of the cosmos breathtaking.