The theory that the universe is a hologram explained in under 5 minutes

Listen to the first episode of our new podcast where scientist Matthew Headrick explains one of the most mind-blowing ideas in physics.

Below is a transcript of the episode.

Welcome, everybody to what is the first ever — the inaugural episode — of the new Brandeis University podcast, "The Take: Big Ideas Explained in Under 5 Minutes," where professors explain core concepts of their research in under five minutes.

I'm Lawrence Goodman with the Office of Communications. With me today is Brandeis University associate professor of physics Matthew Headrick, who is here to explain what is really a mind-blowing theory in physics, the idea that the universe is a hologram. It's also called the holographic principle.

And this is a real theory. It's not science fiction and Professor Headrick is an expert in it.

So thank you very much for joining us.

Great to be here.

HOST: So let's start at the very beginning. In a nutshell, what is the holographic principle?

HEADRICK: Well, as you said, the holographic principle is the idea that the universe around us, which we are used to thinking of as being three dimensional — we have three dimensions of space — is actually at a more fundamental level two dimensional and that everything we see that's going on around us in three dimensions is actually happening in a two-dimensional space.

HOST: Great. So let's break it down even further. This two-dimensional plane, what's it made of? It's made of what you call information?

HEADRICK: Right. So similarly to the bits and bytes that live on a compact disc, which encode, for example, a piece of music — on this plane, that's where the bits that fundamentally make up our universe live. That's where they're encoded and what they're encoding is what we see going on around us in three dimensions.

HOST: And when you say information, can you give me an example of a piece of information or unit of information?

HEADRICK: The concept of information is very general. When we're talking about computers, we think of bits and bytes and megabytes and so on. An example in physics of information would be, for example, the positions and velocities of physical objects.

HOST: And so you're saying that this information on a two-dimensional plane encodes for our three-dimensional universe?

HEADRICK: Exactly. Like in the compact disc example, it encodes some piece of music. In this case, it encodes what's going on in our universe.

HOST: You're now working on a big project with scientists around the world funded by the Simons Foundation to use the holographic principle to reconcile general relativity with quantum mechanics.

HEADRICK: The problem of combining quantum mechanics and Einstein's theory of relativity is one of the hardest problems in physics. So quantum mechanics is a theory that is usually used to describe things happening at very small scales, like atoms and nuclei, and so on. Einstein's theory of relativity is used to describe gravity and the universe on large scales.

As theoretical physicists, we're not satisfied to have two different theories. We need one, unified theory which encompasses both, and that's a very hard problem that theoretical physicists have been working on for the better part of the last hundred years. It turns out that this idea of the holographic principle or the universe is a hologram, although at first, it might seem like a completely random idea, it actually helps us to solve some of the thorniest puzzles that arise when you try to combine quantum mechanics and general relativity. That's why we're excited about and that's why we continue to study it.

HOST: And there you have it, the holographic principle explained in under five minutes. We're going to be doing a lot more of these podcasts in the coming months so I hope you join us for, "The Take: Big Ideas Explained in Under 5 Minutes." Brought to you by Brandeis University.

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