Lex Fridman and Brian Keating: What is Space Dust?
I recently discussed the challenges of exploring the early universe due to pollution…no, not smog… that’s for LA only :-) but what about in our galaxy at large? That’s the subject of this conversation with Lex Fridman
Lex Fridman: You didn’t win the Nobel Prize. BICEP2’s leaders didn’t win the Nobel Prize, because of some space dust.
Brian Keating: That’s right.
Lex: Which one is the moon? Which one is?
Brian Keating: That one’s dust.
Lex: The space dust, yeah. What are we looking at? Why is space dust the villain of this whole story?
Brian Keating: Well, it’s funny. You know, I wrote these books and I don’t know about you, but when you get all these books. I’m sure you get books, people send in books. They always come in these dust jackets, right? I was like, what the hell is a dust jacket? How much dust is raining down any moment on? I mean, this is immaculate, this room is Russian tidiness galore but in a normal house. How much dust is raining down? It’s not really part until I wrote a book.
I realized I’m writing a story about the origin of the universe. The prologue to the cosmos. And dust is going to cover the story. It’s actually more a story about astrophysics and cosmology than dust. And this is the link between the cosmological and the astrophysical. So, what does that mean? Astrophysics is broadly speaking, the study of physical phenomena manifest in the heavens, astronomical phenomena. Cosmology is concerned with the origin of the evolution, composition of the universe as a whole but, it’s not really concerned with stars, galaxies, and planets per se. Other than how they might help us measure the Hubble constant, the density of the universe, the neutrino content, etcetera.
So we have a tendency to look a little bit, you know, they are like, not all astronomers and astrophysicists are equal. They’re all equal but some are more equal than others. So we have kind of a prejudiced little swagger, right? And cosmologists are studying, we’re using Einstein we’re not using Boltzmann, or we’re thinking of the biggest possible pictures. In so doing, you can actually become blind to otherwise obvious effects that people would have not overlooked.
In our case, when we sought out the signal we were using the photons that make up this primordial heat bath that surrounds the universe luckily only at 3 degrees Kelvin approximately. We’re using those as a type of film onto which gravitational waves will reverberate it, make them oscillate preferentially in a polarized way, and then we can use our polarized sunglasses but in a microarray, format to detect the characteristic twofold symmetry pattern of under rotation. That’s the technical way that we undergo. I mean, there’s a lot more to it.
But there is more than one thing that can mimic exactly that signal. First of all, when you look at the signal if inflation took place, big if, but if it took place. The signal would be about one or two parts per billion of the CMB temperature itself. So a few Nano Kelvin, the CMB is a few Kelvin. The signal from these B-mode would be a few Nano Kelvin. It’s astonishing to think, Penzias and Wilson’s 1965 measure is something that’s a billion times brighter. And that was what? It’s been called 60 years ago since they discovered it. Moore’s Law, your more expert than us, call every two years. So you’re talking about like 2 to the 30th power doubling or something at that. Let’s call it 2 to the 20th something like that. That’s like only a 2 to the 10th as a thousand, all right, correct my math and wrong, 2 the 20th is a million, 2 to the 30th is a billion. So, were outpacing Moore’s law in terms of the sensitivity of our instruments to detect these feeble signals from the cosmos.
They don’t have to deal with the semiconductor fabric factory in Santa Clara, California. They don’t have to deal with meteorites and astronauts and things like coming into the laboratory. It’s a clean room, it’s pristine, they can control everything about it. We can’t control the cosmos. And the cosmos is literally littered with particles of schmutz of failed planets, asteroids, meteoroids, things that didn’t call us to make either the earth, the moon, the planet Jupiter or its moons or get sucked into them and make craters on them etcetera, etcetera. The rest of it is falling and it comes in a power spectrum. There are very few. Thank God. Chic club-sized impact or progenitors that will take out all life on earth. But there’s an extremely large number of tiny dust particles and microscopic grains. And then there’s a fair number of intermediate-sized particles. It turns out this little guy here is the end product of a collapsing star that explodes in what’s called a supernova. Type II supernova.
Stars spend most of their life using helium nuclei protons into neutrons into helium nuclei. And then from there, you can make other things like beryllium and carbon, nitrogen, oxygen all the way up until it tries to make iron and nickel. Iron and nickel are endothermic, it takes more energy than gets liberated to make an atom of iron. When that happens there’s no longer enough heat supplying pressure to resist the gravitational collapse of the material that was produced earlier, so, the star forms goes inside out. That’s how scientists discovered helium. Helium was discovered in the sun. I don’t know, did you know? That’s why it’s called helium. They went there at night. Helium means, “helios” as the god of the sun. It was discovered in its spectrum from observations of the telescope like 150 years ago. It wasn’t discovered like when oxygen near[?] or iron was discovered. So it’s only a relatively recent comer to the periodic table.
Lex: The helium came after oxygen on.
Brian Keating: Oh, no. First, hydrogen forms into helium. So that’s the first thing that forms.
Lex: No, in terms of discoveries.
Brian Keating: Oh, yeah, after oxygen. Yeah, I think Priestley and others, the Dalton discovered it in the 1700s. Now, helium was really only discovered from the spectrum of looking at the sun and seeing the weird atomic absorption, called Fraunhofer lines in the solar spectrum. But when it tries to make iron there’s no longer any leftover heat, in other words, there’s heat leftover from fusing as the son of a plasma physicist. Hydrogen nuclei, you get excess energy, plus you get healing. So that’s why Fusion Energy could be the energy source of the future and always will be. No, no, no. Hopefully, it’ll come up sooner than that. And so doing trying to make iron, it takes more energy It doesn’t give off enough energy the star collapses, explodes and what it sprays out is the last thing it made. Which is that stuff. Luckily[?] for us. Because some of that coalesced and made the core of the earth onto which the lighter like silica and carbon and the dirt and the crust of the earth were formed. And some of that made its way to the crust. The iron made its way to the crust. Some of that your mother ate and synthesize hemoglobin molecules and hemoglobin has iron particles in, it’s quite an amazing substance. Without it e wouldn’t have our red blood, we wouldn’t exist as we are.
Lex: Is this a very long complicated mom joke?
Brian Keating: I’ve done enough dad jokes my quotas up. So I’m taking this object seriously not all of it gets bound up in a planet. In fact, forming planets is very inefficient. And so there’s a lot of schmutz leftover, some of which gets in the way of our telescopes looking back to the beginning of time. And some of those molecules like iron are used in compass needles, right? They’re magnetized and magnetic fields in our galaxy can align them and make the exact polarization pattern that we’re looking for. As if the compass needles get all aligned. That’s like the polarization of the dust grain it’s like that polarizing filter. That means light polarized like this will get absorbed and light polarized like this will go through. So it’s absorbing as making a hundred percent polarized light out of an initially unpolarized light source.
And that’s what happened and what we ended up claiming on March 17. I’m sure if you were there you might remember this at the Harvard Center for astrophysics. There was an announcement, there were like three or four Nobel Prize winners in the audience and the Bicep 2 team, which I was no longer leading. I was still a member of it. In fact, in the announcement, the first person they mentioned besides, “thank you all for being here as me and my team at UC San Diego.” Although, I wasn’t invited to go to the press conference because that is very complicated. It’s a little school up there in the Cambridge area. And so, they ended up making this announcement that we had discovered the aftershocks of inflation. We had detected the gravitational waves shaking up the CMB, and on that day passed, Lex Friedman podcast back when it was called artificial intelligence. Brian Keating Tegmark said, “Goodbye Universe. Hello, Multiverse| and hello, Nobel Prize.” He saw that as confirmatory evidence not only of inflation, not only gravitationally but of the Multiverse. Goodbye Universe. Hello, the multiverse.
Lex: Multiverse is a natural consequence…
Brian Keating: Consequence of inflation. Yes. According to its prominent supporters.
Lex: Yeah, and of course, leave the poetry to Brian Keating which he does masterfully. Okay, so that the excitement was there. I mean, maybe the initial heartbreak for you is there too? That is some of the darker moments you’re going through. But broadly for the space of science, there’s excitement there.
Brian Keating: Huge excitement. And I often note that this is a problem that what I called, the science media complex. Because oftentimes you’ll see things like past guest Sara Seager, Venus life exists. And that will be really, it’s fascinating, right? With the work that she’s doing or colleagues are doing and Clara who was on your show as well. That will be on the front page, New York Times, Boston Globe, San Diego Union-Tribune. It’ll be above the fold make headlines around the world. And then six months, 12 months later as a case for us retraction. Page C-17 of the Saturday edition that nobody reads underneath the personal. So we have problem signs. If it explodes, it leads and we get this huge fanfare and this is not unique to my experiment.
This happened with an earlier discovery of the so-called Martian life of discovered in Antarctica. Which was announced after peer-review and we weren’t peer-reviewed at the point when we made the announcement. We had a press conference and there are other reasons that the team leaders felt it was important to do that so that we don’t get scooped by a referee as unethical. We thought we had done everything right but that’s confirmation.
Lex: There’s like levels to this level.
Brian Keating: Yeah, and they were funny levels. And there were people, me warning about how we would be interpreted and wanting to also make sure that we put all the data out including the maps, which we still haven’t released. And so, there were a lot of reasons to be skeptical but the public never knows this. I’ve made a rule that if I’m ever in charge of doling out large amounts of science funding. That you should keep an option, in other words, you should have money for publicity. It’s fine. Have money for your press conference. But hold in reserve in a bond to be used, hopefully, never. But if it’s to be used an equal fund for the retraction. If should occur.
Lex: So you would like to see because that’s a big part of transparencies. To me in the space of science at least that’s as beautiful. It tells a great story. There’s excitement. So there’s a cliBrian Keating of the Triumph, but there’s also a cliBrian Keating to the disappointment at the end because that also eventually leads to triumph again. That is the drama that sets up the triumph. With Andrew Wiles from Oz, I think that’s not his last name, whatever is like the ups and downs of that, the rollercoaster, the whole thing should be documented.
Brian Keating: That is science. And when we don’t do that then we cultivate this aura that excludes other scientists often from minorities or women barrier that you have to be Einstein. Like Einstein came out of the womb and he was just like this guy with curly? No, he wasn’t. He wasn’t bad at math. That’s all nonsense. Do you know what he said he attributed his success to, Lex? He said, I never asked my dad what happened when I ran alongside a light beam like a kid, and thank God I didn’t because had I he would have told me the best answer of the day which by the way, he would create 20 years later as a 26-year-old in the patent office obviously in Switzerland and in so doing by delaying when he asked these questions. He said, I approached it with the intellect of a mature scientist, not a little kid and I wouldn’t have accepted the same explanation.
So sometimes assume that scientists are infallible, inevitable omniscient beings. I think that really does a disservice. Bill Gates said, you know, Einstein wasn’t always Einstein and we cultivate this mystery and allure at our peril because we’re humans until we have artificial Einstein, which I don’t think will ever exist.