The Origins Podcast with Lawrence Krauss - What's New in Science With Sabine and Lawrence | Ghost Murmers, New Wires, Cosmic Questions, And AI cures?

Episode Date: April 24, 2026

I’m back with my friend and colleague Sabine Hossenfelder for another episode of “What’s New in Science”. Spending time with Sabine was a nice chance to step away from my physics lecture series for a bit. I know many of you have been enjoying the lectures, so don’t worry, they’ll be back soon.In this episode, we covered an incredibly wide range of science topics. Sabine opened with reported claim that the CIA used quantum magnetometry to find the downed pilot in Iran. The report, in the NY Post, looked fishy. We explain why it is. Then I described a new discovery in the physics of material that may solve perhaps the biggest problem in AI now: heat generation in computers. Sabine talked about a new claimed Big Bang Theory that might have some relevance to quantum gravity. Then I countered with a discussion of yet a new result that suggests the standard model of cosmology may have troubles, or that observers are wrong. After that, Sabine introduced a paper describing a possible new way to measure gravitational waves. I think it is a fine piece of work, though it is not clear if it is practical. If it were, then the huge interferometers that are now being used could be replaced by ‘tabletop’ detectors. We will see. Finally, I described an amazingly interesting news story that might have implications for the future of medicine. It also demonstrates what one person, with determination and wealth, can do to possibly cure their own maladies. Sid Sijbrandij, a billionaire tech CEO of Gitlab, was diagnosed with inoperable spine cancer, and launched an amazing program of diagnostics, AI data mining, and a group of scientists who developed vaccines specific to his genetic makeup. After implementing all the procedures, he has been cancer free for a year. While this is beyond the reach of people without these resources now, Sid’s story demonstrates the potential power of combining AI and genetic medicine in the future.As always, an ad-free video version of this podcast is also available to paid Critical Mass subscribers. Your subscriptions support the non-profit Origins Project Foundation, which produces the podcast. The audio version is available free on the Critical Mass site and on all podcast sites, and the video version will also be available on the Origins Project YouTube. Get full access to Critical Mass at lawrencekrauss.substack.com/subscribe

Okay, here we are and welcome to a new episode of the Origins Podcast. One of my favorite segments here is my friend and colleagues Sabina Hasenfelder, and here she is across the Atlantic to talk to me about true things and not true things and interesting things and some things that may not be so interesting and we'll decide. So, welcome. Good to see you. It's always good to see you. And I think you should have the chance of leading off with quantum murder.

So go ahead. Yeah, quantum murmurs, ghost murmurs. So I got a lot of questions about this because there were some headlines saying that the U.S. government used some long-range entanglement, quantum entanglement, to find a missing soldier in Iran. And, you know, I was like, how the hell is this supposed to work? And so it's a device that supposedly called a ghost murmur. And the word murmur refers to like heart murmurs because they can measure the heartbeat of the soldier in a desert over dozens of kilometers away, supposedly.

And so, yeah, well, this is all very entertaining. So, you know, I thought about what it might possibly have meant. And you can already. gas is probably not long range quantum entanglement and so on. But the reason I want to talk about this is that I saw like in the online discussions that people are really confused about what you can actually do with quantum technology and whatnot. So long range entanglement is a real thing between two particles and it's been measured over distances of hundreds of kilometers. So, you know, they did this famous experiment in on the Canary Islands or something.

between photons. And so this is all well and good, but you're not going to measure a heartbeat with it. Like these are super inefficient experiments that take a long time to work out that you get to see even a single photon. This is not camera quality or anything. So, yes, long-range entanglement is real.

And you can actually also use entangled photons to improve these. imaging of certain samples. Like this is something that people have tried in the laboratory. Basically, instead of one photon, you take two that are entangled so they share some information and only one of them scatters off your sample, whatever that may be, you know, biological samples and material, whatever. And then you recombine these two entangled particles.

And from that, you get some information about the photon that. scattered. And you can beat certain resolution limits with that because you get like this extra leverage from the entanglement, loosely speaking. And also I think one of the reason people looked at this for biological samples is that it in, you know, it infers less momentum on the on the on the samples. So if you want to image some tissue that's very fragile, you don't want to destroy it. maybe that's the thing you want to use. And it works. It's been done.

But we're talking, you know, about scales like a centimeter or something, like not dozens of kilometers. And also, like, if you look at, you know, the gain that you actually get from these really complicated quantum methods, like generally you don't get very much out of it. So I think that at the moment, like this is like, you know, a curiosity. It's something that you can do, but it doesn't really have any good practical purposes. It's also sometimes, I've seen it referred to as ghost imaging. And I suspect maybe this is like where the word ghost came from. Who knows? So, yeah.

And so in the end, what I thought that they, what probably happened is, so there are very, very sensitive infrared sensors. So actually, you know, there are two types of infrared sensors. Like there's the cheap ones where you actually send out light, infrared light from some source. It's kind of like a radar. And then you look at what comes back. So those are fairly, you know, inexpensive. And then there are the really, really expensive ones where you actually catch that stray light. And yes, you can use those to find people or, you know, everything that's kind of warm in a cold night.

Like also animals and stuff. So, and I, you know, I can imagine that, especially in a cold desert, it'll work quite well over long distances. And so the best ones of those sensors, they use certain quantum effects. You know, it's a complicated semiconductor layer thing, you know, with some, it's called a super lattice, I think. I actually don't know exactly just how it works. But, you know, it uses some quantum effects. And they probably almost certainly use the. device like this because this is like the state of the art. And yeah, that's cutting-edge technology.

And I'm pretty sure the U.S. government probably has the best of the best of the best. And maybe they tried this out in Iran. I mean, why not? It's actually, you know, if you think about it, like, you know, warm human body in a cold desert is kind of the best case you can think of. And so I suspect that somewhere along the line, it's kind of like Chinese whispers, you know, someone misunderstood exactly what actually happened. And so this was kind of my best guess. Maybe I should also add, yes, there are quantum technologies. It's called quantum metrology, where you use quantum effects to measure very weak fields

very precisely. And it's been done most famously, I think, for magnetic fields and for the gravitational field. But impressive or not, this is nowhere in the range where you could measure the magnetic field of a human heartbeat over tens of kilometers away. So this is like, I don't know, 20, 40 orders of magnitude of the charts. Yeah. So, yeah, I'm almost done. This is like my closing sentence. So I think there's a lot of confusion about, you know, just, you know, quantum.

what can quantum actually do? And so I thought it's a good example to explain just what's reality and what's fiction. Yeah, no, I think that, I was trying to figure why we were talking about this and then I think that's the good reason. But I want to add some things because

you know, when you sent me the topics, you're going to talk about, you sent me this New York Post story titled The Secret, Never Before Use CIA Tool that helped find Airman down in Iran. If your heart is beating, we will find you. used a futuristic new two called Ghost Murmur. And I read it and I thought, you know, I read the story and it's in a newspaper and I thought, wow, this is interesting, but it just doesn't seem to make sense. And I'm almost amused to say that I started to look up for other references.

And I found another place which I don't think is much better than the New York Post, namely Scientific American. And they actually had an article about why it was impossible and why it was nonsense. but and it confirmed my feeling. But the point is, indeed, quantum metrology and quantum magnetometry has been used to be able to try and observe the heart

with devices that are right on your chest. And what they do is they use the quantum properties of the observing material to measure what, as the magnetic field changes, it changes to the quantum phase of the system. And you can measure that, in certain carefully prepared quantum systems,

and they can use that to barely, to barely detect the heart at the surface of your chest with the limits of existing technology. And that's, if they're right there, they can barely detect your heart. But obviously, when you go, and the magnetic field falls off so that by the time you're a meter away,

it's basically a million, the effect is a million times smaller and they can't detect it. By 10 meters, it's a trillion times smaller. And so there's zero way this could be done. And absolutely right. If they used any technology, and they did, it was probably infrared technology to find this guy. But it is fascinating to me, of course, that the word quantum, and this is always the case. The many put the word quantum, it seems anything is possible in the media,

as far as it's concerned. And I think it's really important to point out that quantum effects can be, are useful, but they're not real magic. They may seem like magic at certain. At certain, certain times, but, but, uh, this, this was the case of it being too good to be true. And it literally was too good to be true. And it's, and I think the other thing I want to say is that, is that when you read something like this in the, you're supposed, just begin to ask yourself, if you could do that, what could you do? So the idea is to keep it open mind, but not so open that your brains fall out. It just smells totally wrong. And assume it is, unless you can, unless you find confirmation otherwise, because, uh, the idea of being

there's just so many reasons, not just the distance, but think about it. This is in a helicopter, a device with whirring blades and mechanical and electromagnetic things going all over the place, the noise as possible electromagnetic environment you can imagine, and the idea is you're trying from a helicopter somewhere far away to measure the electromagnetic field due to the human heart beating, which you can barely tell at the surface. Everything about it smells wrong. And so if it smells wrong, I think what I want to encourage listeners to think is that it probably is wrong, unless proved otherwise. But, you know, quantum mechanics is wonderful, but there are limits that quantum systems are very specially prepared systems.

If they weren't, quantum mechanics wouldn't seem so crazy. If you didn't have to do anything to see quantum effects, then we'd all find it kind of heuristic and we'd understand it in an everyday sense. the quantum world is strange and weird because it is so difficult to isolate and we're finding new ways to do it. But on our scale, it's very hard to see quantum effects. So anyway, that's what I'd add. Well, I think one of the reason people get excited about this is that this just tells you that I spent too much time on social media, but there is a fairly large fraction of people who are fairly convinced that the U.S. government has some, you know, has made some secret breakthrough in the foundations of physics that they're not telling us about.

And so if, you know, if you go down this road, then you start believing all kinds of things. You know, they have anti-gravity. You know, they can travel faster than the speed of light. Quantum entanglement measure, heartbeats over, you know, dozens of kilometers. Communicating with the aliens. Basic stuff already. And so it's kind of a difficult conversation to have where, like, like, Personally, I'm convinced, like, the U.S. government certainly has some technology that's beyond what we know.

You know, there's some classified stuff that we have no idea exactly how it works. But I strongly doubt that there are orders of magnitude better than what we can do in research labs. But that's an argument, you know, where I can only say this is what I believe. Like, I don't actually know this. Well, I mean, you could, well, okay, if you, first of all, you're absolutely right. and I have to deal with this all the time. And the biggest thing that people believe, of course, is that U.S. government's hiding aliens and alien technology.

And that, it just, I keep reading supposedly sensile people. There's an article, even in the free press, which I must admit I'm liking less and less as a news source about someone who's interviewing people about UFOs. It's just the idea that, yeah, the U.S. government has these fast, invisible, research, it's not even that true. DARPA, which is, you know, one of the, the U.S. government's advanced research projects agencies, and, you know, they do

classified stuff, but they do it most often with the research community. So, in fact, there's, you know, there's some elements of it that are, that are classified, but it's never, it's always on the cutting edge of what you can do in laboratories because they're working with the best scientists in the world. And so, I mean, I've been involved in DARPA once or twice, and one hopes that they're doing cutting edge work.

But yeah, the idea that they're capable of vast things from communicating with aliens to traveling faster in the speed light, all these things people want to believe. And, of course, the movie industry does a great job of encouraging that. And politicians seem to do a great job of encouraging it. And unfortunately, the media does a great job of encouraging it. So it's up to you and I to bring people down to Earth. And that's what I hope we did with this ghostwormer thing.

I was actually completely disgusted with the, you know, I know the New York Post is marginal, but the definitive way in which they said this happened, it's become like the National Inquirer or something like that, and so are many other media. So the quantum world is wonderful, but wonderful within the limits of reason. And applying reason is not too bad a guide when thinking about the real world. Great. Okay, so now you have a more down-to-earth topic. Well, I have to admit, you know, when I read the title of the paper,

it was like, what the hell is this? But you're going to explain it. Yeah, yeah, no, I can get this down-to-earth as you want. I'm going to talk about wires and metal. And this is an interesting and very down-to-earth thing, but it could be quite important in the result, is that, you know, when we, well, actually, for modern applications, heat dissipation in electronic,

systems is very important. In fact, it probably could be a defining aspect of our technology as our technology becomes more and more governed by these incredible AI farms that are using incredible amounts of energy with hundreds of thousands or millions and maybe even billions of processors. One of the biggest sinks of energy is the release of heat, the idea you have to cool these systems down. In fact, I was just thinking how much things have improved. Do you remember in your early laptops, that fan that was so annoying that always came on when you were using it. And you don't hear it anymore in laptops because they've gotten much better at heat dissipation. Well, in any case, this is a very down-to-earth result, and it sounds boring as anything.

But it involves a material called Theta-phase tantalum nitride. And it is a material that's been explored. And the perhaps not earth-shattering, but maybe technology-shattering result, is. that when they look at a certain phase of this material, this metal, which is a very specific crystalline lattice structure, it has a thermoconductivity that's basically almost three times that of copper. Copper is the best thermoconductor we have at room temperature, and it's used to dissipate heat in systems.

And that may not sound very important, but dissipating heat turns out to be incredibly important for everything from computers to almost any other electronic gadget. And it was thought that, given what we knew about solid state materials, that the upper limit of heat transfer, copper has heat transfer of what's called 400 watts per meter Kelvin. And it thought that that was close to the upper limit. And this is 1,100. And what's really exciting, again, almost the reason for doing this and talking about here,

is that it suggests a very different mechanism that it's almost like superconductivity, but for heat, in the sense that this specific crystal lattice is set up heat in cold systems and at the quantum level is vibrations, and vibrations are quantized, we call them phonons. And as phonons move around and scatter, they basically dissipate initial coherent energy into heat. And what this system has is called a gap. And what that means is that phonons can travel without dissipating, without interacting, without interacting with each other. The phonon-phonon interaction is almost zero because if you look at the quantum system, there are no energy states that two photons can collide and go into. It's like a superconductor.

The reason superconductors are that way is electrons can't scatter into another state and therefore lose energy. So this is a very specific crystal and material where the phonons have been discovered to not be able to. scatter with each other. And also, because of the Christian nature, the scattering of phonons, the quant of heat, if you wish, and electrons, the stuff that's carrying electromagnetic properties and materials, that coupling is very, very small as well.

It's a surprise, and it means that this technique of kind of searching for materials with this gap for phonons and small coupling of electrons could pave the way for a whole set of new materials that have very high heat conductivity, factors are three better than now. And it's not clear that theta tantleum nitride will be able to be produced in vast quantities.

It may or may not be able to. But if that type of thing is, it could literally change the game. When you're spending hundreds of millions of dollars trying to get rid of heat from an AI farm, Okay, reducing things by a factor of three is not trivial. And so even though there's very down to earth thing about a ugly material, you know, with complex properties may not seem earth shattering, it can change technology.

And specifically what makes it interesting is that it suggests a new avenue to search for things that go beyond what was thought was possible before to do nothing more simple than dissipating heat. Basically, that's the basic thing in physics is getting dissipating heat. You couldn't imagine anything you might think more boring or more essential, but that this is a new way of doing it. And I think it's, it's, it could be interesting. So that's my take on it. You really have to read the title of the paper if you have it there because it was,

it was this like super technical, like no one would understand from the title of the paper. How is even relevant? Yeah, yeah, yeah. Exactly. Oh, and what's the title of the paper? I do have it somewhere here. And, um, and, uh, and, uh, Let's see if I can have it here.

It's in science. Okay, I think I can click it up. And it's called metallic Theta Phase Tantlum Nitride has a thermal conductivity tripled out of copper. Actually, that's not too bad. Yeah, yeah. Well, if you understand what it is about. So I had to give it a double take and then think about why it might have been relevant.

So, but yeah, I mean, you're totally right. Like, this is like potentially, like if they can manage to actually produce the stuff at a reasonable cost, at a reasonable stability, at a reasonable scale. It's potentially a big thing because the bottleneck in making computers smaller, you know, cramming more computing power into smaller space is heat. Because transistors are getting smaller. and because like this is the thing that they've been trying to do like for 10 years is that at the moment most transistors are in a plane like they're sitting next to each other on board but what you would really want to do to make use of the space is to put them on top of each other and now you have a huge heat problem you know you don't want your your motherboard to just melt away yeah and so this is where this sort of discovery can really make a big impact. And, you know, people have thought of all kinds of crazy things. Some actually want to pipe little fluid channels through the transistors or cool them with lasers.

And this is all like, you know, in theory, it might work. But in practice, I can't really see it work. It just makes the whole thing, you know, you have this extra equipment from the fluid channels. Yeah. From the laser, right? And that makes it bigger again. So what's the point? So what you really want is you just want a different material that does the job.

And that's what's wonderful. I think the idea is that we're still learning, even in this modern world, which is really important. In fact, especially in this modern world, we're learning, as we learn about the quantum properties and materials, again, using quantum again, we're learning that, you know, there are lots of fascinating, still new things to discover about materials and developing materials for specific purposes. And I love the idea, you're right, instead of getting rid of all this, instead of doing all this fancy technology, just having a new kind of wire to solve the problem would be amazing.

And, you know, in fact, one of the reasons that Elon Musk and others want to send these AI farms, data farms into space is there are two reasons. One is to get all the energy from the sun 24 hours a day, but also to cool it. And so this, you know, some basic things about materials, which we shouldn't, we shouldn't forget that there's a lot to be learned under the sun and even the simplest things of looking it in a laboratory building in the new kind of material can have a dramatic, dramatic impact. And so there we go. Hard-nosed physics that might not seem exotic and normally wouldn't make the headlines

of the New York Post, but nevertheless important, unlike the things that do make the headlines of the New York Post. Now, speaking of things that maybe are less, are certainly more exotic, and in my opinion, maybe less relevant. Why don't you talk about something that was called a new Big Bang theory? I hate when I read those words on the headline because I almost always close my eyes,

but in any case, go ahead and talk about it. Yeah, it made some headlines, and I got questions about it, so I looked at the paper, and it wasn't terrible. You know, a lot of people come up with one or the other Big Bang theory, and most of them are nonsense,

in the best case, in the worst case, they're just bluntly wrong. And also there's this issue like they're all kind of empty. You know, there are lots of things that you can attach at the beginning of the universe where we can't test it. And then you can say, well, you know, we just invent some kind of mathematics and that's pretty much it. So I like this idea because it's fairly minimalistic. And it ties into a pretty big,

question in quantum gravity. That's this issue that when we take Einstein's theory of general relativity and we quantize it, which can be done, then the theory just breaks down at high energy. So especially if you want to say something about the Big Bang, it doesn't work because the energy is just too high. So that's kind of disappointing. But we do have a version of gravity, which is called quadratic gravity that doesn't have this problem. And it's loosely speaking because the coupling constant

doesn't have a dimension. So it's like formally, all these problems with the infinities you have when you quantize Einstein's theory, go away in this nicer theory. The problem is it doesn't seem to describe the gravity around us.

So what do you do? Well, the idea is that you say, well, at low energies, like around us in the solar system in galaxies, you know, at larger cosmological scales, we have Einstein's theory. And then if you go to, if you go to, sorry, I just thought it stopped working.

And then if you can cut this out, if you go to higher energies like at the big. I'm not going to cut that out. It's kind of cute. Go on. If you go to higher energies, like at the Big Bang and presumably also inside of black holes, but they don't write about this in a paper,

then you go over into this quadratic gravity, and then you can actually quantize the theory. And so this is basically what they looked at in the paper. And I quite like it because it's quite minimalistic. You know, you just have this, like this one assumption, like this is the high energy limit, and now let's look at what comes out. And then the miracle happens.

And so what they get is, They say, well, in the early universe, we nicely get this phase called inflation, which a lot of astrophyses believe has happened, like this exponential expansion. That loosely speaking explains why the universe is so large. And then they have an exit from inflation where all the matter is created, and then the universe looks at the way that it looks today. So it's all well-in-dise. there is a little bit of fudging going on there, which is that the maths actually doesn't tell you exactly how this transition looks like. I mean, so they make some reasonable guesses,

but, you know, deriving it as something else. So they had some freedom to make things work out. Still, I think, you know, it's a starting point. You know, if we ever want to say something about the beginning, I see you're absolutely not convinced. If we ever want to say something about the beginning of the universe, I think we need a theory similar to that. Your turn.

Yeah, okay. Well, I looked at it and I, well, you're right. It's not garbage. Absolutely. I, um, it's, you know, it's people reaching for something to do and something that might help them do a calculation that might be relevant. It, it, as you say, it involves this theory that, isn't the theory of the world that we live in,

as far as we can see, at least at low energies. And they do some real calculations, but again, there are many qualifiers. Well, there are big debates about whether this is really a good calculation for this theory because it's got problems of ghosts and other things and, you know, mathematical problems. Maybe if we finesse this and we push this and we squeeze this and we lift this, we can maybe get it

because we know where we want to go, and lo and behold, when we do that, we can get it to sort of go where we want to go, and moreover, when we do, we can make, you know, there's certain constraints on it in order that it isn't ruled out by observations, so we can, quote, unquote, make predictions, namely we can show it's consistent.

So it's kind of a squeaking something where you know the answer, you know what the answer is. And at the very beginning, they still have to assume something, which is still, to me, without that theory, the most likely picture of how the university

came into being, namely from nothing, obviously. And the idea is that, you know, there are these no boundary conditions, and there's a calculation you can do that shows with something called a gravitational incident on that the universe would begin in an inflationary stage. And so they posit that, and then they show how this theory, which is manageable, that may not have anything to do with nature, but the theory which is manageable, if you manage it in certain ways, it might allow inflation to end, and you might be able to get predictions that look,

that are consistent. And so it's yet more people trying to say something, but it is true that if we had a quantum theory, one would hope it would do this. But this is knit. And so it's nice that specific calculations could be done. In particular, one of the things everyone always, because looking for gravitational waves

is the kind of holy grail now of trying to understand the early universe, they make a prediction that the gravitational waves are larger than a certain amount. Again, it seems to me that since this is new phenomena near the plank scale, at the very beginning of the universe, and the amount of gravitational waves is proportional to the scale at which your new phenomena happens, and if you're close to the plank scale, you're going to get gravitational waves. So it's not too surprising that this theory predicts them. The point

is that there was another theory. The first person to think of kind of refining gravity and using gravity itself to get this phenomena called inflation was Guy Sterebinski. And he had a version of inflation which was not that a model that's not that different than theirs

but it disagrees with observations. So what they've done is add something that allows them to do something very similar and not disagree with observations. And that's intriguing, but I wouldn't say earth-shattering. It's nice to see it's possible, but I don't think it's, I don't, I wouldn't write home yet about it myself as my own feeling.

I don't, what do you think? I think the authors are going to quote you in their CV. Lawrence Krause said, it's not garbage. Well, it's not that. And I know the authors and yeah, they're good people. But yeah, it's interesting to see. Look, I think the point of this is that we're going to, that quantum gravity is going to be necessary to understand the beginning of the universe.

And you can make tentative efforts. And this is at least a model where you can do calculations instead of just talking. So it's nice to have a model where you can do calculations. And in this model where you can do calculations, sort of do calculations, you can push it to get some reasonable calculations. and that's not uninteresting. Let me, let me, so maybe in their CV they'll put Lawrence Krause said it wasn't uninteresting.

Okay. Now to something else in cosmology. Yes, which may, which I've always said wasn't that interesting, but it's getting more interesting. People, some people are still hung up on it. And,

and of course, it's called the Hubble tension. And you realize, and we've talked about this before, and I'm sure we'll talk about it again. And the idea is the Hubble constant is the expansion rate of the universe, is probably the most, in my opinion,

it's the most important number in cosmology and maybe in physics, because it determines the whole scale of the universe. But there's two ways to measure. One is to directly measure the weight at which the universe is expanding. That's not so easy, because you have to measure galaxies

and see how far apart the far away they are and how fast they're moving. That may sound easy, but it's not. And for now almost 100 years, we've been doing it and getting better and better, but it's still hard, because you have to make assumptions about the distance of galaxies, and you have to use tests to see if you're measuring the distance right. Measuring the speed of galaxies away is pretty easy, but measuring the distance is the hard part,

because what you do is you see how bright they are, how bright they look, and then you assume for some reason you know how bright they are, and then, of course, given the fact that the intensity of light goes as one over the square of distance, you compare how bright they look to how bright they actually are to get the same. their distance. And well, that's fine if you know how bright they actually are. And there's different ways. The original way is something called a Cepheid variable star. If you look at stars and galaxies, there's certain stars that vary at a regular rate. And the rate at which they vary and the amplitude is, the rate at which they vary is proportional to their brightness. You can tell that

from nearby stars. And so if you look at Cepheid's in distant stars and you see the rate at which they vary and you see how bright they look and you think you know their intrinsic brightness, and you assume they're the same kind of sepheids as you see here in our galaxy, then you can make these extrapolations and try and determine the distance to these galaxies. Anyway, and we measure that. So that's, that business has been going on for 100 years. A business that's been going on for now less than 100 years, probably almost 30 years now, is to use the cosmic microwave background radiation, the best observable in the universe.

Something you can measure the temperature of it to four decimal places, and it is really what turned cosmology from an art into a science. And that will allow us to determine the properties of the universe when it was 300,000 years old. Then you use what's called the standard model of cosmology, or the best we can think of, a universe that is flat and it's full of dark matter and dark energy and regular matter, and you plug things in and you use gravity, use standard calculations. You can predict what the expansion of the universe today should be.

and the problem is they're slightly different. Okay, in using the early universe, you get a number that's something like 67 plus or minus 0.5 or something like that, kilometers per second per megaparsec, that's a unit. And the other way you get something like 72. Now that may not seem like a big difference, especially in a field where those numbers used to differ

by factors of three or four, 25 years ago. And as someone who grew up at a time that different people would measure the expansion rate and get a difference by a factor of two, a difference of 2 to 3 percent doesn't seem like a lot. But it's getting better. And recently, press release came out from a collaboration of many universities. What you can see here are measurements of the early universe and extrapolating to what we think the Hubble constant should be today. and then all of these others are measurements of the direct expansion rate of the universe, and you see they don't look like they agree. Now, and this is the most recent compilation, which is claimed to be, I mean, it's not really any different,

but it's just basically a consensus version, namely it bring a lot of people together who've been measuring the expansion rate in different ways, and they talk a lot, and they combine their results in some way, and they say, yeah, now we've got a consensus version, and that number is now that number is 73.5 plus remand is 0.81 kilometers per second per megars parsec, which even the untrained eye can see is different than something like 67.5 kilometers per second mergum barsek. And these error bars, if you believe them, suggests that there's a real tension between these two. Now, there are two solutions to this. And the one that gets the most press is, well, maybe we're using.

the wrong model of cosmology. Maybe there's something new. Maybe dark energy is changing in its abundance in a way that changes things. It would have to change in a very strange way to make this agree. Maybe the theory of gravity breaks down and the standard gravitational arguments for how you extrapolate from the early universe today breaks down. Maybe there's some new physics, some new particles. Maybe there's lots of new stuff. Isn't that neat? Of course, that's the kind of thing theorists spend their time on. The other possibility, is that there's some systematic errors in, clearly there's not statistical errors,

because if you look at these, they're roughly statistically distributed in a way that doesn't seem too strange. There's some outliers every now and then, which there should be if you measure something many, many times. So if you believe these statistical errors is a problem, but astronomy is governed by systematic errors. The history of astronomy is governed by systematic errors.

errors are things that you don't really have control of in just observing. Like, for example, let's say sephiads in different galaxies were different than sepheids in our galaxy because the metallicity or some other thing was different, or maybe something like that. That would mean that there's some fundamental thing that you can't control in your observations that shifts the whole thing over. I'm still, if you ask me, I'm still on the side of thinking that there are some systematic uncertainties. And one of the reasons, which I actually shouldn't have stopped that image when I did, so I'll do it again, is if you look at, is my little cursor showing or not? Yes, it does. Okay. There's this one measurement here, and I believe this is the

measurement, Roselisle from Wendy Friedman and others, who use a different way of looking at, well, they look at sepheus, but they also look at, what's called the red giant turnoff branch where it turns off as a way of determining the brightness of systems. And by the way, and there are many reasons that I, from my own work, think that's a much more reliable way of kind of measuring brightness

and therefore distance measure. When they did that work, they came up with this number. And Wendy was the head of the Hubble Key Project that determined the original Hubble Constant 10 or 15 years ago with the Hubble. Space Telescope. And you can see that that, it's certainly an outlier, but using that kind of slightly different

distance measure, it certainly gets much closer. And so the question I have ultimately is, is have we really, do we really understand how to determine the distance to distant galaxies? And so I still think this is up for grabs. It could be a fascinating pointer of new technology, certainly the new result, makes the tension a little bit stronger. I don't think it changes things a lot, but it caused me to look back at it.

And the answer may be in the devil, maybe in the details. I'm betting on observational issues rather than some dramatic new things in cosmology. Obviously, most of the newspapers and other articles about this are betting on the other thing. So anyway, it's there.

It's a real tension. We'll talk about it again. But that's the situation. So, your turn. So, well, it's been interesting to see the story of the Hubble Tension develop, which has been around like for almost 10 years now or something. Oh, yeah. Quite a long time. Yeah.

And so I remember that like when it when it first came up, pretty much everyone thought it was a systemic problem, you know, with one of the other measurements, whatever. But, you know, one after the other, all the people that I know, they all move to know it's almost certainly a real thing. So now you're kind of the anomaly, you know, who holds out and says, well, it's something about the way that you measure things. So I don't really, you know, I'm not an observational person, so I don't really know. But what the hell is going on with the strong glancing data? This seems to be all over the place. Yeah, well, I think the reason it's all over the place is that it's a new technology. And I think, you know, I think, but that's an indicator, right?

the fact that there's new data and it's all over the place is suggest that maybe there's something we don't understand about the techniques and maybe there's something we don't understand about the measurement technology. But, you know, it could be, I've said this to you before, it could just be that I'm a dinosaur. Sabina, I've been around since, as I say,

one group measured the Hubble Consum to be 42, another one measured to be 100, and both of them had errors are plus or minus 5. And so I've grown up in an air. era where I was highly skeptical. But I do think that new techniques, you know, like this red giant turnoff, the turnoff branch of diagrams of stars, give different numbers. And so there's still something to be learned.

I think it's unlikely, it's unlikely that there's a systematic error in the causing microwave background. I think that's less likely. I mean, but there could be. but the reason I'm driven to this is once again the smell

the smell test if you look at the ways that you might want to reconcile it the solution is uglier than the problem generally to me and that suggests to me that you know that

one should be very careful before jumping on the manwagon of new physics I guess that's my attitude well did you just make an argument from beauty So maybe, you know, as I said, I'm not an observation of astrophys, but I can say something about the theory side, which I think you, you jumped over a little bit too quickly. So, yeah, so if it's, if it's not, you know, an issue with the way that we do the measurements or how we analyze the data or interpret the data, then there are still two different possibilities.

The one is to throw out a whole of general relativity and say, well, we need. a new theory of gravity, right? So some modified whatever, maybe it's a quantum effect. God knows, I've seen it all. Or some kind of modified thing that you might like. Yes, anyway. And then the other less extreme option is to say,

well, we don't need an entirely new theory. We just need a better model within the theory that we already have. And it's this second option that I think is actually quite plausible because if you look at the model that we currently use, which is called Lambda CDM, or sometimes it's called the concordance model, you know, it has this weird assumption that the universe has the same average density everywhere, basically.

You know, it's the same in every place. It's called the cosmological principle. And I've always found this to be very, very fishy. And so the problem is, though, if you throw out this principle as a mathematical assumption, then the equations become much, much more difficult to the point that you basically can't do any calculation with them. And so this is the point where you could say,

well, you know, this is like the cure is worse than the disease, right? So let's stick with what we have and then try to figure out what else we can do. But my suspicion is that sooner or later, we'll have to use a better model anyway. You know, this is like the cosmological principle. I think it's wrong. It's got to go, we need a better model.

Better model. So I think, you know, just saying new physics is a little bit too extreme, but I also don't think it's just a measurement artifact. I think we're kind of somewhere in the middle, basically. Okay, well, I think that's a very rational view. When I'm thinking, by the way, of the things where the solution is worse than the problem, and not so much the cosmological principle. although all our measurements seem to suggest the universe is pretty much the same here or there,

at least where we can measure. It's the idea of weirdly stranging dark energy and all of these things. It has just change in a very weird way to solve the problem. And those are the theoretical pictures that I find very difficult to find reasonable. I mean, once again, I kind of have this, I call it the kosher test. If a particle physics comes up with a model that is doing something that solves a problem in particle physics, and then it has applications in cosmology, that's a good thing. If someone invents some weird model to solve a problem in cosmology, that's fine for a PhD thesis,

but it doesn't mean much because you can always invent weird things. And so so far, there's nothing, no fundamental ideas that suggest a better fundamental picture, of how to get from the early universe to now and solve that problem. There are a lot of crazy theoretical ideas. But you're right, there could be other assumptions like the cosmological principle. You know, we might be in a vast bubble. There's lots of things people have done.

But it still seems to me you have to really stretch and work really hard to solve the problem. Whereas assuming this very difficult thing to measure distances to galaxies might have a small systematic error, might solve it. We'll see, and I'm sure we'll have some more episodes on it. Anyway, it's nice to know that there may be problems

because those are where progress is made. Now, you're going to talk about something that actually I think is a quite neat result, which is coming back to the not quite tabletop but almost tabletop way of doing something in cosmology. Right. And it's actually

it ties into the first thing that we talked about with the, how you can use quantum effects to make very precise measurements. It's a good example of this. So So this is a group of physicists who want to measure gravitational waves in the laboratory with what's called a cold atom gas. So it's basically like a few million or something, atoms, literally atoms, like a cloud of

atoms, they get evaporated from some kind of material, and then they trap them with electromagnetic fields, and they cool them to like milly-calvin. and you get some quantum effects that span throughout the cloud of atoms that makes them very, very sensitive to the slightest disturbances, and they want to use this to measure gravitational waves that pass through the laboratory. And if they could do this, it would be a really big thing because at the moment, you know, we measure gravitational waves

with interferometers that have arms that are some kilometers length. So shrinking it down to a meter or something, that would be a huge advantage. And there is, you know, there are some subtleties, though, with the proposal. So for one thing, you know, just doing your smell test. It doesn't sound immediately plausible because, you know, we can measure very weak gravitational fields with quantum effect. It's been done. And we know that this works, but the gravitational waves are like super weak, even compared to that. So how would you do something like this?

So what they basically say is that this cloud of atoms kind of amplifies the effect, and they wouldn't measure exactly the actual shift. in the, sorry, I should start it. What they want to do is they want to bring these atoms in a state of higher energy, so an excited state, so that if the gravitational wave passes through, they fall down and then they emit a photon, and this is what they can measure. So otherwise it's kind of unclear, like what do they actually measure about the thing, right? So they want to measure this emission.

And so the idea is that if the gravitation, wave passes through, it very suddenly change the emission of this light. And so the one thing that it does is that it did change the frequency of the light, but it's such a ridiculously tiny shift that I don't think you can measure it. And so, but they say it would also like slightly, so it's basically a combination of the frequency shift and the direction into which the light goes. And so they say, well, if we can keep this cloud of atom atoms coherent for long enough, and if the measurement is precise enough, then we might be able to measure gravitational waves,

if they are strong enough in a particular frequency range, which is fairly long gravitational waves. So it's actually, if I remember correctly, it is actually larger wavelength than what they currently measure at LIGO and the other. Much larger. Gravitation. Yeah, yeah. So it's more in the range of Liza, E-Lyzer. Yeah.

So it's like millions of kilometers or something like that. Yeah. And so that would be pretty cool. So, I mean, it's not like they can do this tomorrow, but maybe in 10 years or something. Who knows? So I think that would be really exciting. Yeah. Look, I actually read the paper in detail because I've thought about these things a lot.

and it's a nice, it's a very nice paper. It's a very, in my opinion, a very solid paper. There are issues I have with it. It does make a, it looks at, it looks at the interaction of a single atom in these two states with a very, with an idealized gravitational wave, a plain wave coming through. And it uses a simple model,

basically treating light in a very simple way. And so there are assumptions that are made to make the mathematics doable. And when you make those approximations, you do get a result. The gravitational wave changes the photon field in a way that causes remarkably there to be a directional dependence of the frequency, of the emitted light. Averaged over all angles, it doesn't change, which is not surprising.

It's a good test that the thing is true. It doesn't change the rate at which atoms relax when they get excited. But somehow, because of the fact that gravitation waves, it's called quadrupole, when this radiation is emitted, there's a sort of a shadow of that quadrupole, a signal of it, which is that the frequency of the light that's emitted it changes somewhat over the angle, depending upon whether it's done. Now, of course, how do you measure that with single atoms and single photons?

And that's a much more complicated problem, and they go into that and look at it fairly in some detail, again, making some approximations. And in the approximations, if they push things, then it looks like, in principle, you might get an observable effect. Now, in order to get something that's, if they're looking at the kind of phenomena, that are that are being talked about in in you know as possible gravitational wave sources then those phenomena are such that uh uh you probably need you know you're looking at uh sub millimeter frequency ranges so that's a sub millimeter sub millerhertz i should say

sub millerhertz not you know very slow millerhertz okay that means you know it's it's also very slowly. You're looking at merging supermassive black hole mergers or some other things. Galactic binaries, galaxies colliding. Those are the kind of sources of those gravitational waves. And to get to the kind of sensitivity that might be comparable to look for those things,

you probably need a billion atoms or something like that. But certain cold atomic systems have been kept in this nice, beautiful sort of quantum state for 100 seconds because you have to keep this thing cold and they say that's great because, you know, in LIGO you're looking at 1,000th of a second by the time

light goes back and forth. This thing can be integrated over 100 seconds maybe. And so maybe it would work. It's at the limits of it might be able to work. There are lots of issues that aren't looked at here. This is a simple approximation with the more detailed real treatment

of the system really give that same kind of effect, would numbers go down by a factor of a few and make it impossible maybe? But also, what they do is they assume that a billion atoms is the same as a billion times one atom. But these billion atoms are interacting in a system together, and they're not like just a billion copies of a single atom. And does that more complicated system of dealing with a lot of objects going to change things, is it going to produce noise backgrounds, is it going to be produced noises, in the detector. This is something which I think is a real effect. The question if it's ever

measurable at the level that's of interest is not known. And I think, you know, I suspect that everything is being pushed to the limits, but maybe. And therefore, I think it's, it's a really neat new approach. But to add some historic perspective, when Ray Weiss first thought of using a gravitational interferometer, I think it was 1967. Okay. And hey, maybe you could measure gravitational waves. $3 billion later, 50 years later, with teams of 1,000 people, they finally got it. And that went, okay, and so that was with a technology that you knew would work. I mean, that was an idea that was clear.

A gravitational wave changes length, and an interferometer can measure the change in length. There's no doubt about it. And this is something that's more tenuous and interesting, but whether you can go from that idea to a technology that works and that actually applies is going to be a long way off. But I still really enjoyed the paper. I thought it was an interesting new idea. And any time you can get new ideas that allow you to, in principle, to tabletop measurements of gravitational waves, it's great.

It's, we'll see. But it's certainly in the level of, I'd go from not, I wouldn't call this not uninteresting. I would call this the level of interesting. So there we go. So when I looked at the paper, I were surprised that it isn't that far beyond current technology. Like if we're talking about like a billion atoms, like that's, I think the current record is something like a hundred million or something. Yeah, yeah, yeah.

And sure, you still have to like, it's still a billion is more than a hundred million and you need to have it at very high quality and there's this issue with the noise and so on and so forth. but it's not like 40 orders of magnitude off. Oh, exactly. No, in the size of the system you need, it's great. The question is, can you measure, can you really measure the photons in that system in a way that would see this very, very small signal? You know, we'll see.

But at least it's a real effect, at least in this idealized system where light is treated in a simple way as a scalar phenomenon. And it's a real effect. And it doesn't look too far from potentially being plausibly measurable. And so we'll wait and see. But I think it's a very nice piece of work myself.

Okay. And now to something completely different. I want to end with another nice piece of work, which may or may not have any applications beyond that of a certain billionaire. But, you know, and it shows what can be done if you have the resources. And also, to be fair, the incredible dedication. and ingenuity and willingness to work.

This is a fascinating story. It's been reported a bunch of times. I've heard about it. It's about a billionaire founder of a company who got cancer and basically they claimed cured himself and it not really cleared himself. But his name, I'm going to brutalize it here,

is Sid Sijbendage, and I'm sure I'm saying that wrong. But he's from the Netherlands and he started something called GitLab, which is basically an open-source, collaboration tool for software developers. And his big thing is open source. And the company which began in his home office grew and it's used all over the place as a way of amassing

information on data so that people can develop better tools. The idea is to get better understanding of data. And it's an amazing company with the oversource, open source, even their own documentation of what they do is open source. and so you can now to go over 3,000 pages of information on their own version of how they're amassing data. So he's a good data guy and a good open source guy. Anyway, in 2022, he went from his garage to being a billionaire in this regard because it's a useful tool that's used by over, by most major businesses. It now has 2,500 employees and all sorts of things.

Anyway, he discovered in 2022 that he had spinal cancer. And even then, he was kind of an amazingly brave and heroic person. It was a six-centimeter spinal cancer that, and he went through the worst possible things you can imagine. Operations that are incredibly painful, radioactive therapy, chemotherapy. He had to have four blood transfusions during this time just to stay alive. and he stayed alive and bravely through this many people would give up. I mean, this guy does sound like an amazing human being. But in 2024, the cancer resurfaced.

And they basically said, you know what? It's resurfaced and we don't have any, we don't have any therapies at this point that we know of that'll help. So, you know, have a good life, however short it's going to be. And then he did what he said. He went from manager mode to quote founder mode. and manager mode, as he said, was using existing systems to find the best of all possible operations. Founder mode is going deep into everything and examining and examining every single assumption and idea and diving deep into that and being willing to try any new avenue even if it's not sort of an existing. mode of therapy.

And so what he did is he immediately, because he had the resources and the dedication, he put together a team, a team of radiologists, oncologists, and also his AI people, and basically used every diagnostic test he could on his own system, every genetic sequencing on his own system, amassed 25 terabytes of data on himself. And this is a guy whose whole career is based on open source data mining. and then assemble the team of experts to look at that results, including AI, to look for possible therapies that might work, and then also have the people who could then do genetic sequencing and tools

to develop vaccines that were unique to his DNA based on a whole bunch of possibilities that had been discovered by the DNA data mining of possible therapies that have been applied to other cancers. and then, and doing all of that, and then doing something else, which is doing the treatments in parallel rather than in series. Normally doctors, because they're trying to isolate what works and doesn't work.

They try one thing, and then if it doesn't work, they try another and another, and that's sensible if you're doing a research project. But if you're trying to save your life, he basically just did them all in parallel. It doesn't matter if one of them works, it works. Anyway, and after all of that,

the cancer is now in recession. Now, that's been since 2025. So let me say a few things. Cancer goes to recession. It's only been a year. So the idea that he's cured is not so clear. But what I find fascinating about this is, of course, this is an amazing number of resources thrown at it, is the fact that we talk about the utility of AI. You and I have talked about it in a lot of different ways.

It's not a panacea for everything that ails. us, but what AI is useful for is mining huge data sets and looking for things that may have been, you know, difficult to find otherwise. And this is an example where his amassing 25 terabytes of data in every possible way the data on his own body and his own diagnosis every single day, allowed AI to at least explore different therapies. And then, of course, the other aspect of this is the incredible power of genetics of developing vaccines based like mRNA but that are based on your own DNA that might that might attack a cancer that have been shown to potentially produce a kind of T-cell that might work and and then and then his case

supplying them all at the same time and you know I assume which and many of which could have killed him but it's clear that this kind of incredible war for one man did something. And it shows the power of what I think AI will be used in medicine, which will be to data mine. The more data it has, the more it'll be able to look and perhaps find therapies that may be useful. They won't find new miracle cures necessarily,

but it might provide avenues that might be good for looking at. And then the other equal power of genetics right now and genetic medicine, where we tailor vaccines to individual people. this was a guy who had the money and the energy and the willpower to do it, but societally, we may be able to mimic this at some level as a way to do better medicine. And in his case, it looks like a miracle, not a miracle, because there are lots of ideas that were around, but he was willing to put himself on the line and put all of his money and not all of his money, but whatever, and use himself as a guinea pig, and a very brave

individual. And he's in recession. a new company, and I hope for his sake that it stays that way. And it's a wonderful story about both the realistic power of AI and the potential genetic medicine. It's not a miracle, but an interesting lesson. So that's why I wanted to introduce it. I think it tells us something else, which is that good ideas come back. Because this idea of personalized DNA-based medicine, you know, for each individual tailored to

their needs and so on. This has been around since decades. Yes. And so it started, I think, around the time when they started sequencing the human genome. And then at some point it was like, it's all hype. It's never going to work. You know, the body just doesn't work this way. And diseases are much more complicated and so on and so forth. But I think we're now beginning to understand that actually, yes, it can work. It's just much more difficult. And this point is kind of, we're beginning to see that it's possible, but it's ridiculously time-consuming and ridiculously expensive.

And so it'll be a long time until this technology trickles down, you know, to a level where normal people actually have a benefit from it. Because not everyone, God knows how much he spent on this, probably several hundred million dollars or God knows what. You know, I'm just guessing. I have no idea. But, you know. You have sent a whole team of researchers and paid them, you know, and yeah, absolutely.

No, it's a really good point. In fact, it brings it home. Actually, in probably 2005, I may sound strange, but I, for a short period of time, I was vice dean of the medical school at my university because the dean was interested in the idea of personalized medicine, of genetic medicine, trying to combine science and medicine. and we talked about it then, and, you know, it seemed like, you know, a great idea about pie in this guy then.

But the other aspect is that, you know, I'm suspecting that a smaller version of this in the future, doctors with access to AI and large databases will have a better, a useful additional diagnostic tool to look for therapies than, you know, then just searching on Google. And that's going to help medicine as well. And I think that's, yeah.

Anyway, but your point is, right, it's come back and it's incredibly expensive but like many things, the costs may go down, and it's certainly both tools will help medicine. And the interesting thing about this, well, it's advertised as if he got AI to solve. There's one announcement I saw where he got AI to cure him. That's not the case.

Data mining, plus a whole tool of doctors and therapists and people who could do the genetic engineering. And so it doesn't mean that doctors are going to be out of business or researchers are going to be out of business because of AI. That's another thing that people throw out. Well, as always, it has been a pleasure and fascinating to unravel the real world and the world of hype

and nevertheless the wonderful world of science with you. And I thank you once again for a wonderful time. Well, thank you. That was very interesting. Okay. You take care until the next time. Bye-bye.