Dr. Brian Keating
speaker
1,291 appearances
4 recordings
4 series
first heard Dec 2024
last heard Sep 2025
Dr. Brian Keating’s voice in public audio — every appearance, attributed to the second.
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Appearances
I've traveled literally trillions of micrometers and billions of seconds to be here, and we are going to explore this universe together. Cosmology is the oldest science known to humanity. Since cavemen and women, people have wondered, where did everything come from? We're not going to do any alien autopsies or anything in this class, but we are going to cover a lot of fascinating questions.
Where do we come from? Where are we going? What is the universe made of? How can we possibly understand the grand landscape of the cosmos? When you look back in space, you look back in time. It's amazing we've been able to do this, to study the properties of the cosmos, time scales of billions of years, size scales billions of times bigger than our own.
And now the question is, can we go back to time equals zero? Can we go back to before time equals zero? And what does that even mean? I hope in this course to keep striving and asking these great questions, because without great questions, there can be no great answers. And without great answers, there can be no understanding.
You know, Jordan, I always joke, our profession, I call it the second oldest profession, right? I mean, there have been universities since the University of Bologna in Italy was established in 1082. And look how much has changed. There's a guy or a girl taking a piece of rock and scraping on another piece of rock. How innovative. After a thousand bloody years, we've done almost nothing different.
Okay, so there's PowerPoint, and that's not that much different, let's be honest, right? But what if there were the opportunity to bring in literal the visualizations that they've done on my first course, and I can't wait to see on the second course. And my third course is – see, what's nice, I'm an experimental physicist. I'm not Brian Greene. I'm not –
manipulating wormholes like my friend Kip Thorne and so forth, who did the science behind the movie Interstellar. I was the advisor to Christopher Nolan. I'm not a theoretical physicist. So what do I do? I do experiments. The more experiments, the better. But you only do another experiment because some aspect of the previous experiment failed. And that's fine.
That's part of the iterative process of science that makes it not only so important and so annealed, so hardened by truth and the process of attempting to achieve truth, imperfectly as it may be, but getting things wrong. Look what happens when you get something wrong. Let's be honest. It's a surprise, right?
You didn't think you were going to go down and you're going to discover dust instead of the Big Bang, which is what happened to me in describing my first book. We thought we saw the gravitational wave aftermath of the inflationary universe that we talked about in my first podcast episode with you. But instead, that led to the Simons Observatory.
It's led to a $200 million project that is now going to not only look for the gold, but also look for the dragons, look for the dust, look for the things that are in the impediments. So the surprise was not a failure at all. I mean, look, when you solve a puzzle, you get a little bit of thrill. And remember when you were a kid, you had a Rubik's Cube, you had this thing or that.
You'd solve the puzzle, and you would do something that no adult does. You'd do it again. Like, my kids do this all the time. They solve a Rubik's Cube, then another one messes it up, then the other one solves it. And, like, I already solved it. Like, I don't need to rewrite my PhD thesis. Like, I already wrote it. But there's a little bit of that thrill that you get when you are surprised.
I say this to my students all the time. I say, flaws... in your experiment, in your theory, lead to new laws. It's not like we study. Do you know, Jordan, that we're made of matter, right? But in the early universe, we think that there was almost an exact symmetry. It's one of these guiding principles of physics, that there are symmetries. Conservation of energy is a type of symmetry.
Angular momentum's conservation is another type of symmetry. Displacement, the symmetry, those are all the things that we say exist. The laws of physics shouldn't change. They should not look different in a mirror or upside down or on Pluto or in Arizona. It should not make a difference who you are, where you are.
It's kind of the great democratic process of science known as the Lorentz principle of Lorentz invariance that Galileo really crystallized and then later eventually— Fundamental things apply everywhere in all directions. Fundamental truth to the extent that we can perceive it.
And so, you know, when you do something and you find out, well, this is not correct, like the fact that the postulate was, and all the greatest scientists thought, there should be equal amounts of matter and antimatter. Well, guess what, Jordan? We wouldn't be here if that were true.
All the matter particles would annihilate with the antimatter particles and the universe would be a universe of complete, barren, sterile radiation. Pretty boring unless you happen to be a photon. But that's not the case. And it's obvious just from we exist. We know that that's not true. We can observe it. I refute it thus. Kick the rock. It's made of matter. Where's all the antimatter?
Is it segregated in some galaxy that we haven't been to yet? No, we don't think that's the case. So where did it go? Well, we have to look. How symmetric is the universe? How beautifully, finely balanced, tuned, if you believe in an intelligent designer? How... finally tuned, did he tune it to be? Well, it turns out he did a spectacular job.
Because for every particle of matter, there was another particle of antimatter. Except for there was one, for every billion particles of antimatter, there was a billion and one particle of matter. So the two matching a mirror image matter and antimatter particles, they destroyed each other. And what was left? One particle of matter. And the rest was a bath of photons. Right.
It is not a rounding error. It's exquisitely balanced. Now, we don't know why. Some theists will say it's intelligently designed. And you can ask certain questions. How well designed does the universe have to be? In other words, how finely tuned? You have a good ear for classical music. My wife enjoyed talking to you about it. You know, she plays the violin. I play Spotify.
So I have no musical ability whatsoever. But you could perceive the note A, 440 hertz, right? Your ear can actually perceive if it's 441 hertz. In other words, one out of 400, so less than 1%, a quarter of a percent mistuning, you can perceive it. How well tuned does the universe have to be in order for us to be having this conversation?
And then the supposition is, well, if it's extremely finely tuned across a whole vast panoply of different areas, from the strength of these constants, the number of protons, to the number of antiprotons, then you might start to think this is suggestive. But it's not a scientific hypothesis, right? We can always say God, and we can always say there was no God, but you can't prove it.
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