The Origins Podcast with Lawrence Krauss - What's New in Science with Sabine and Lawrence | Cosmic oddities, Black Hole normalities, Quantum Batteries, and remote-controlled cockroaches

Episode Date: August 3, 2026

Happy August! . Heading back to North America as we just concluded our Origin Project Adventure to Cyrpus and Greece, where we felt the heat, and avoided some wildfires while having some amazing positive experiences as well with an amazing group of 26 travelers. Please stay safe and try and stay cool this month. To help distract you from the heat, I hope you will enjoy this latest conversation about new discoveries in science with Sabine Hossenfelder. As always, we try and deconstruct the facts behind the headlines, and also explore new strange corners of our universe. This episode begins with some new observations of the Bullet Cluster of galaxies. This cluster contains two galaxies that have collided, and seems to have provided evidence for exotic dark matter that has passed through the collision unscathed. Not so, says a new analysis, which claims evidence for more dark matter in the form of black holes and other less visible normal matter. There are strong reasons to be skeptical however, as both Sabine and I agree.Speaking of black holes, a new analysis of collisions of black holes at the terrestrial gravitational wave detectors proposes a solution to the mystery of how black holes in a so-called forbidden gap between 10-20 solar masses and more than 50 solar masses have formed. They provide evidence that some of the black holes observed in collisions have been built up from earlier collisions with other black holes. This hierarchical growth could potentially explain how very large black holes in the early universe form, though it is a long way from 50 solar masses to 1 billion solar masses!Strange goings on at the largest scales of the universe continue to be claimed, as yet another study argues for an unexpected and unexplained cosmic spatial asymmetry. It is hard to reconcile this with the observed uniformity of the universe on the largest scales we can observe via the Cosmic Microwave Background. As a result, it is too early to get excited, even if newspaper reporters love to report on claims that fly in the face of the standard model of cosmology.The Vera Rubin Space Observatory has started its 10 year project to monitor a huge swath of sky every night looking for things that go bump in the night. On the first night, they found a few hundred thousand possible events. With a 10 year movie of the cosmos who knows what they will discover. Sabine introduced me to an article about Quantum Batteries. Are they going to be useful, or just another cute example of how quantum mechanics produces strange phenomena? Time will tell. Finally, I couldn’t resist introducing a story about cockroaches with nervous system implants that allow their motion to be remote controlled by experimenters, with tiny diving suits attached that allow them to breathe underwater for extended periods. It is claimed that they may help in undersea rescue.. Wow! Maybe so… What will they think of next?Until the next time.. enjoy!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

Welcome to the Origins Podcast. I'm your host, Lawrence Krauss, and I'm joined by one of my favorite people, Sabina Hassenfelder, to talk about what's real and what might not be real in science. And to hear her incisive comments about interesting topics or topics that may not be so interesting. And so this time we have many different topics from the universe down to cockroaches. And I want to go right to you, Sabina. And I know the minute you talk about, you talk about. me of this topic, I knew it was a topic that's near and dear to your heart, which is the bullet cluster. Indeed. So the bullet cluster has been offending me for 15 years. So, but let's start at the beginning. So what's the bullet cluster? The bullet cluster is actually two galaxy clusters that once upon a time in the very far distant past must have passed through each other at fairly high velocity. And so it's called the bullet cluster because it looks a little bit like there's a bullet going through if you look at the distribution of stars through the cloud of the other cluster. And so that thing is fairly far away. I've forgotten exactly how far some billion light years,

whatever. But we do have a lot of observations of it. And the reason the bullet cluster has attracted so much attention is in particular that we have two different observations. The one comes from gravitational lensing. And it tells you basically where the mass is located. So depending on how strongly the mass curves light behind it, the more mass there has to be

to make it work. And the other is X-ray emissions that mostly come from hot gas that's in the clusters. And so the famous picture of the bullet cluster shows that these two things are not in the same place. So the bulk of matter in the two clusters is not in the same place as the hot gas,

which is most of the matter that we know of. It should be. So this is the key question, basically. And so the common explanation for how this could possibly have happened is that these clusters had two components, the one being the dark matter, which is cold and does not emit any x-rays or any other visible light, so we can't see it with optical telescopes and electromagnetic stuff and so on. And it's basically collisionless, so this part goes, you know, just through, essentially.

And then there is the hot gas, which actually collides with that of the other cluster, and it deforms and it gets slowed down. And this is, so the explanation, why these two things have become delocalized from each other, so they're no longer in the same place. And the Bolic Cluster observation has, I think it's from 2009 or 2008 or something, it's sort of 15, 16 years old or something like that. So it's become one of the go-to arguments in favor of dark matter, and not just this, but also against the alternative, which is modified gravity.

And the standard explanation for why it's not compatible with modified gravity is that modified gravity, basically you have normal matter, but then it creates a different gravitational field. And this is all well and good. You know, you can fumble around with the law of gravity or small acceleration or large distances or whatever, but it will still point to the same. location as the normal matter because that's the only source you have. And he said that's the standard, you know, the standard explanation.

And so now the news is that there's a group from the located at the University of Bonn, where they have reanalyze what's going on with the bullet cluster using the newest data from the James Webb Telescope. And they say, well, actually, it looks like the bullet cluster is compatible with modified gravity after all. And their main argument to make a long story short is that they say we've underestimated

the amount of boring normal dark matter in the cluster, stuff like black holes, brown dwarfs and all this sort of stuff. And so if you adjust these numbers as favorable as you want them to be

into the direction of modified gravity, then you can make it work out. So it's worth mentioning that one of the authors of the paper is Pavel Krupa, who is known to be a strong supporter of Mond, modified Newtonian dynamics, and he's written an entire series of papers about all kinds of observations,

how they're supposedly evidence for Mond. So I always mention this, like, if you know, if these arguments cluster around one particular person, you know, you have to be a little bit more careful. But of course, it doesn't say anything about the analysis in the paper, which I think is basically fine

for what I can see, you know, because there are, you know, there's some flexibility and how you can push the numbers. I have a little bit of a headache with the general conclusion because I have always thought that the bullet cluster

isn't a particularly good argument one way or another. There was, like 15 years ago, there was a long debate in the literature about whether the bullet clusters even compatible with dark matter, not because of these two observations with the gravitational lenses and the hot gas, but because of the enormously high relative velocity that these two galaxies must have had.

So in a standard universe with dark energy and dark energy, matter lambda CDM, you can calculate what's the probability of two clusters hitting each other at the required high velocity. And several groups actually argued at the time that the probability is very, very small. Whereas in modified gravity scenarios, it can be much larger. And so, you know, my conclusion about this has always been, well, this is, you know, statistical outlier. You know, don't draw too many conclusions from this one thing. And so this is why I'm always a little bit, you know, if people quote this one example,

this thing has ruled out one thing or the other, I'm always saying, yeah, I'm not having it. Yeah. So with that in mind, I also don't quite buy the conclusions of the not new paper. But nevertheless, it's kind of interesting to see what you cannot conclude from the observations that astrophyses itself. You know, it's an interesting, I looked at the paper, I looked at the claims,

and yeah, I mean, the bullet cluster is interesting because, yeah, I've always thought of it as, you know, as a reasonable argument for dark matter against Mon, but it is astrophysics, as you say, and there's always so many systematic things that you can't control. But I have to say, I was skeptical. By the way, the reason they say, you know, not that there's more matter,

but they argue that the black holes, neutron stars, would also be largely collisionless and therefore go through each other, unlike the hot gas. So if you put a lot of mass in these things instead of hot gas, they could go through each other just like dark matter could, and without getting stopped. The normal matters in the center where it would collide, I mean, the hot gas would collide and coalesce and all of that. But what I found suspicious, and I didn't know about the authors,

but the minute I did it is they basically have to claim that there's almost a factor of two, error in the amount of mass associated with, you know, these with neutron stars and black holes and matter that could account for this. And this thing has been studied so much that a factor two error is a fairly large, doubling the amount of matter in this system is surprising. Let me put it that way. Claiming that there's twice as much stuff in black holes and neutron stars as everyone else

had assumed before suggested to me that they're pushing the limits of their modeling. And basically, I think they, my impression was if somehow this was a statistical outlier where there was a lot more neutron stars and black holes than there normally is in galaxies, then maybe it could explain it. So I was skeptical just whenever I see that kind of change, a factor of two, that everyone else is wrong by the amount of matter in this, in black holes and neutron stars. You know, people study how much, you know, for all these astrophists, study what the fraction of black holes,

the neutron stars should be from stellar evolution. And a factor two error struck me as at least it raised my spider sense a little bit as, well, maybe they're pushing the limits of this. So, but it is interesting that if you put the limit, push the limits and maybe it's all statistics, as you point out. I mean, these systems are, you know, this is one system. and potentially maybe for some reason that I don't know, there could be a lot more black holes in neutron stars in this system

than in other galaxies. Maybe that would be the case, but I'm suspicious. But it is interesting, as you point out. One of the reasons I'm happy you brought it up is that it is one of the examples that many people, and I, to be fair, have used it as an example of dark matter, and it's nice to know that we have to be a little more careful when we rule things out when it's astrophysics,

because the things we rule out often come back to home. haunt us. I say that in the case of dark matter. In my career, from the time I was a junior faculty mayor, even earlier, cold dark matter had been ruled out probably five times by 1995 by the time. And of course, each time it resuscitated, either like a savior or a villain, depending upon your view. So one should be very careful before. One says never in astrophysics, I think. That's the lesson. Now, speaking of the next, the next, one is, I was going to say it's more boring. It's not boring, but it's, it, instead of showing things are wrong, it could show things are right. And maybe that's less, less interesting. But it is,

but there's been a mystery. And it has to do with gravitational waves and black holes. Of course, the great discovery of LIGO and then supplemented by the other gravitational wave detectors, I understand now there's a few events a week that they actually can now see between all of these observatories, which is amazing. They see the spiraling end of black hole. holes, you know, two black holes or black hole in neutron star, two neutron stars, colliding together and producing gravitational waves. And it's an amazing, wonderful discovery. We've talked about it and the one Nobel Prize and all that.

But once you have enough of these, you begin to look at statistics. And one of the things that was a little strange. Well, there are two strange things about black holes in general, the inferred black holes. One is that stars are only supposed to form black holes up to a certain size. If they get larger, then all this mass gets blown away, and the standard stellar formation of black holes should limit you to something like 20 to 30 times the mass of the sun.

Any object that's larger will not collapse directly into a black hole. Most of the mass, if it's a star, most of the mass will be adjacent. or thrown away and etc., etc. And then there are these supermassive black holes that are hundreds, but not just hundreds, but thousands and millions of times the mass of the sun. And there are two questions. First of all, LIGO and others have seen some black hole collisions where they infer the mass of the black holes,

and they're like 100 to 200 to 300 to 300 times the mass of the sun. Well, 100 times, 50 to 100 times. That's a gap. That's a region where there shouldn't be. any black holes from stellar collapse. So what gives? That's the first thing. The second thing is you have these million solar mass black holes. How did they get there? Did they form at the beginning of the universe before you had stars and things somehow collapsed spherically to form a big thing? Or did you form small black holes that merged and merged and merged with collisions of the

type you see? And it happens slowly, but over billions of years, maybe you can do this. Well, there's an reanalysis or there's an analysis now of a lot of this black hole data from Ligo and the other observatories. And the interesting thing is, of course, when the black holes

are orbiting each other emerging, did those black holes form from stars or were those black holes formed from earlier mergers of other black holes? For example, if the average sort of large stellar black hole is like 10 to 20 solar masses, if you

emerge, you're going to form something like, you know, 20 to 40 solar masses, and, you know, twice the average size of a stellar mass, of a black hole that's formed by stellar collapse. And so if you have some of these black holes in these mergers that came from previous mergers, you'd expect on average one to be about twice the mass of the other. And also, if you have black holes form from stars that were originally, orbiting each other and they collapsed while they were stars, you'd expect their spins to somehow be aligned. And so, but on the other hand, if you had a big black hole that was formed by a merger

of two little black holes, which were originally stars, and then it collides with another black hole, you'd expect the spins not to be necessarily aligned, and you'd expect to be an isotropy, one to be twice the mass of the other. And so the idea is that can they look at the statistics of this? And when they do that, and also, by the way, if the black holes are not original, if they're not from stars that collapse, but instead they're black holes from two black holes that merge,

when they merge, they spin up, and their spin should be very, very large, but 70% of the maximum amount that's allowed by general relativity. So if you see objects where systems where one is, twice the mass of the other. It's spinning with a spin rate about 70% of the maximum outer gener relativity. And there's no real correlation in the spin axes of the two objects, because if they were never lined together at the beginning,

their spins can be random. And when they just have done a reanalysis, the suggestion is that some fraction of the events that they're seeing are clearly not original black holes that form from stars, but some of these objects are black holes that were previously binary systems that collided together and made a bigger black hole. And that can explain why they're suddenly seeing black holes that are too big to have been formed for stellar collapse. Because if the black holes formed from two stellar collapse black holes that merged, of course they're going to be bigger. So there's good evidence for something that seems reasonable, which is some fraction of the events that LIGO are seeing,

are actually black hole mergers where one of the black holes wasn't from a star, but it itself was from a previous merger of two other black holes. And that would explain how you can get black holes in this mass gap, first of all,

and it would suggest that this hierarchical picture of black holes merging and then merging again and then merging again and eventually maybe forming super black massive black holes might work. So this new analysis of data, to suggest that what you might

thought of as reasonable is that black holes build up by merging with other black holes and now we seem to have evidence that that happens. Could solve two big questions, maybe not problems, but questions in black hole formation. First, why do you get black, why are we seeing black holes

in this forbidden region where you should never see black holes that form from stellar collapse? The reason you're seeing it is that the black holes you're seeing aren't formed from stellar collapse. they're formed from the merger of previous black holes. And if black holes do merge at this kind of rate, then maybe you could, over cosmic time, you could explain how you get big enough mergers

to get thousand or million times or billion times solar masses. So it's an interesting bit of evidence that suggests that solves one mystery and suggests that maybe supermassive black holes formed not originally in the early universe in one fell swoop, but from the build-up of black holes that would collide with other black holes that would collide with other black holes. So it's interesting and not unreasonable analysis,

and it's nice that we have enough statistics with now hundreds of black hole mergers instead of a dozen to be able to do something that at least statistically seems to be significant. So that's the result. Any comments? Well, I think it just moves the mystery elsewhere.

Well, I mean, I think what they've done is they've taken the data from the gravitational wave events, the analysis, and reconstructed which part of the distribution came from what sort of merger, basically. And from this, they extract some statistical contributions from these hierarchical mergers. but you know, now the question is like, how do these black holes find each other? Right? I mean, so if you have a star that collapses and it sits there, it's not going around, looking for something else to merge with. And so, I mean, Asthmaelphus had a certain reason to believe

that these things will be rare, which is where they don't find each other. And this is also why the growth of the supermassive, of the originally not supermassive, massive black holes, like the stellar black holes from the early universe, was supposed to take that long. This has been an open question, like, since I was a student, basically. How do the supermassive black holes manage to grow quickly enough to get to the size if they come about by stellar black holes growing?

And I don't think we know this any better now. I mean, it's all well and good to say, okay, well, if you look at the data, it seems. like these hierarchical mergers are actually happening. Okay, that's great. But now, okay, so, you know, how does it happen, basically? Yeah, yeah, no, you know, I agree. It is a surprise that, you know, because stars don't collide very often, right? So if stars don't collide very often, why should black holes collide more? And it's an interesting question, but they, but the evidence is they do. And all I can think of is maybe that there are environments where you get a lot of stars, you produce a lot of massive stars and they're close by each other.

Those environments then, you know, produce black holes that are more likely to be densely, you know, densely created and more likely to experience the gravitational influence of another one. So maybe, maybe we're seeing something about large stars collapsing, you know, there's only in regions where there's large over-density as material and you form large stars and they're nearby each other. You're right. It's an open, it still seems weird. even if you see a 50 or 100 solar mass black hole,

which formed you might think from the previous collision of two other stellar mass black holes, it's still a long way to get to a billion solar masses and it's a lot of collisions. And why it is surprising indeed that this has happened before. This is clear evidence that it's happened before. It certainly seems to convince me that there's definitely evidence for past collisions of black holes that have formed larger black holes that are now in a new

system that's now colliding to form even even larger black hole. So that is happening. And yeah, the astrophys have to explain why these guys encounter each other so often enough that when you only have 100 events, you're seeing it, right? I mean, it suggests that it's happening a lot. And maybe it says something about large mass stars and where they form and how they form in systems. systems that are together because, yeah, they got to find each other. You're right. That's an open question that's still there. But the data tells you it happened, but it may not.

And the other thing about supermassive black holes, which is important, is we're seeing them in the very early universe, right? So it had to happen a lot. If you're going to start with 20 solar masses and you're going to get up to a billion solar masses, that's a lot of mergers and a lot of collisions. and it's got to happen in the first billion years of the universe or less. And so, you know, there's a lot of questions that still remain. But it is interesting to me that at least there's some evidence that even something

as rare as two black holes colliding has happened often enough that in 100 events, at least one of the black holes you've seen happened from an earlier collision of two black holes. That surprised me. Anyway. Okay, good point. So the summary is more work is needed. Yeah, more work is needed. That's exactly right.

And this is often the summary. Now, you're going to talk about something. Confess, I'd never heard of a quantum battery before reading the paper that you suggested we talk about. So why don't you explain what this is all about? Yeah, so I actually don't want to talk about this particular paper. It shows that this was the most recent headline. And I've seen, like in the past, two years or something like every couple of months that there's a headline about quantum batteries

quantum batteries this quantum batteries that and people always ask me like well why don't you talk about this like in in on my youtube channel and and so i i i thought i should explain why i don't think it's particularly interesting i mean like from a like from a foundational perspective like from a theoretical laboratory point of view. It's an interesting idea. It's basically, if you think of a quantum computer, I think this is a good way to think about it. So quantum computer works with qubits. So you have two states that you can put it in superposition and so on. And with the quantum battery, you basically have a kind of reservoir where you can park some of the energy and then you can get it back out. So it's like literally in the in the in the Hamiltonian,

that describes the interaction, you have like an additional part where you can put this energy in and then you can get it out. And because it's a quantum system, you know, it breaks certain limits that standard batteries have. For a similar reason that quantum computers can do calculations faster than a regular computer, these teeny tiny little batteries that are attached to the qubits can break certain scaling limits in how well you can re-extract the energy. Okay, and this is all well and good. Like, I think theoretically it's reasonably well understood. There are some issues with how to realize this and so on.

But the thing is, like, this is not a battery in the sense that anyone, you know, in daily life, understands a battery. Like, they have, like, a storage time of something between a nanosecond and microsecond or something. And these are like teeny tiny amounts of energy that he can put in and put out. So if you're building a quantum computer, I can, you know, imagine there might be certain advantages to it that he can temporarily like push some of the energy there and then you take it out again.

And a microsecond, if you're doing a quantum calculation, can be a fairly long time. So that makes sense. But like we're not going to run the next generation. of electric vehicles with a quantum battery. And so this is like basically the only thing I wanted to say. So it's one of those quantum technologies. Sound great. Quantum battery and, you know,

the breakthrough with quantum battery, whatever. So, yeah, but I think like at least my thinking about it, is like this is a purely research thing. I can't really think of any application outside of this quantum computing. range. Okay. You know, it is true that any time you put the word quantum in front of anything, then it becomes news, including the word quantum leap, which I've always thought was ridiculous, because, you know, quantum leap, I don't know if you have it in German, but in English, a quantum leap is a big leap, a big change. But if it's a quantum leap, it's actually very small

because quantum leaps are very quantum. Anyway, it doesn't matter. But I will, look, I found it, I read through it. And what is interesting, you're right, it breaks the classical scaling laws of thermodynamics, which quantum mechanics can do. And I guess, and once again, you didn't mention the magic word entanglement, but the idea is, you know, a battery does two things, if you think about it. I was trying to understand why they call it a battery. It takes energy in, and then it releases it. Okay?

And so that's what this does. And the point is that if the system is designed to somehow be entangled, with the reservoir of energy. So there's quantum entanglement. It can obviously, because of that entanglement, it can sort of scoop up energy faster than it could classically and not get as hot

as you'd require it as normal classical thermodynamics because there's quantum entanglement. So in some sense, it's never really one system. It's always one system. And you're just thinking of whether the energy here or the energies there. And similarly, it can release energy similarly because it's entangled

with the outcome system. And so, yeah, entanglement allows you to violate classical rules. Quantum mechanics allows you to violate classical rules a lot, and this quantum system allows you to violate classical rules. I had no idea whether, I mean, I got the sense from

this that people somehow still thought that they could ramp up these systems somehow. But these are optical traps. These are as you're saying, it's not ever going to, it doesn't, like most quantum, the reason quantum mechanics is so strange is when you ramp up to our size, the world becomes classical. And there's a good reason for that. It's really hard for quantum phenomena to maintain themselves with correlations and everything over large scales with lots of particles and lots of interactions. And so this is a quantum

phenomena, which is happening on a very limited scale. And it would be just like quantum computers, It's a real chore to try and ramp it up. I mean, people have been, there's a lot of money pointed into quantum computers, and it's still, we still only have baby systems. And there's a reason for that. It's really hard to maintain the quantum world on a larger scale. And we're working, and there's engineering, and it's, you know, it's happening slowly. But this quantum battery, you're right.

I think it's mostly, if it's going to be useful, it's going to be useful as a research topic, but you're right, it's not going to be a battery, a quantum battery. But it just demonstrates something that still people are amazing. by, and maybe we should still be amazed by, but it's a fact that the quantum world violates classical logic and get over it if you have a problem with that. It's just the way, and the point is that the world is quantum mechanical. It's not classical. The classical world we see is an illusion. The fundamental world is quantum mechanical. So the fact that our sense of common sense of what should be allowed is violated at the fundamental scales is just a simple accident of the fact that

where we don't experience quantum mechanics. And if we did, quantum mechanics wouldn't be so weird. But we, you know, so, so yeah, it's, the quantum world is weird, but the world is quantum mechanical. So ultimately the world is weird. That's, I guess, the way I want to say it. Okay. Now, you know, you're, you're, you know,

the topics you picked are much more, you know, I guess we've, there's a dichotomy because you're sort of picking things that seem to violate conventional wisdom. And the topics I want to talk about today, for the most part, except for the last one, are things that just talk about how we can use what we know and it's not too strange. Anyway, I want to talk about the Rubin Observatory briefly because it got in the news. It got in the news because it turned on.

But the Rubin Observatory, which it's interesting, it begins, what's now called legacy survey of space and time, LSST, period. It's an observatory. It's going to observe a large fraction sky every night and with a large, with not only a large telescope, an 8.4 meter telescope, but it's got the biggest camera ever built for astronomy, 3.2 gigapixel. I think, you know, if you and I have cameras in our phones, I think they're 10 or 20 megapixel, right? And this is gigapixel, so it's much larger. So they can see many things at once. And I think it's interesting that they've learned that if you want to capture the mind of the public, you've got to use words that people understand.

So legacy survey of space and time, which comes to LSS, is the original versions of this that I heard years ago were something like large synoptic survey telescope. And who's ever heard of the word synoptic? It's not the kind of thing you want to. But legacy survey is space enough. Anyway, the point is, that this large telescope in Chile has turned on, and it's going to do something rather interesting.

It's going to do a 10-year movie of the universe, where it sees millions and millions of galaxies and stars and other things and looks for interesting things to happen. In its first look, it basically, during a single night, it generated 800,000 alerts of potentially trans... Supernovae or things happening. things happening in the universe. And what's really amazed me is as this turns on, which it's now begun to do, and it's going to do it every night, it's going to look at a large fraction of the sky,

it's expected to generate 10 million alerts every night. So I mean, you know, if you get an alert on your phone that something happened, that's neat, this is going to be 10 million alerts of things happening in the universe, things that go bump in the night, literally. It's basically looking for things that go bump in the night. And there's talk about it being useful, of course, look for dark matter and supernova and stars and other things. And maybe it will. But I think the hope is that if you look every night and you get 10 million bumps in the night, that over a 10-year period, a movie of the universe, you'll see something you hadn't expected.

And I think the hope of everyone doing this telescope is, yeah, it'll give you lots of information on transient events in the universe. It'll increase the data set, well, with 10 million, with millions of a little, every night. It's hard to imagine, you know, the data, just imagine dealing with all that data, trying to figure out what's going on is amazing that you could even do that. So it'll give a lot of information for conventional astronomy. And maybe, they always mention dark matter, dark energy, because it's always, those are the buzzwords. Maybe it'll tell you something about dark matter, dark energy, because you're looking at so many objects and you can look at their motion and

configuration. You can do lots of statistics. But I think the hope is that you'll see something unexpected. And it's not a bad hope. Every time you open a new window on the universe, in the past, we've been surprised. So the Rubin Observatory, I like it because I knew Vera Rubin. She was a wonderful human being. She overcame a lot. At that time, frankly, at that time, it was difficult to be a woman astronomer, and she had to go overcome a lot. And she, and of course, her work led to the basic original claimed evidence for dark matter, which was the fact that our galaxy and other galaxies are rotating too quickly on their outer regions. So I like the fact that it's called, named after her. And I like the fact that it's going to take a 10-year movie of the universe,

but I don't know what it's going to produce. So I wanted to, it just turned on and now we can wait and see. Comments? It's also looking for asteroids, isn't it? Yeah, well, it's looking for anything that changes on a given night. So I'm not sure, the interesting, I'm not sure if it's going to look for Earth killer asteroids, but maybe it can do that as well. There are dedicated telescopes doing that, but it will look for anything in the field of view that changes in a single night. And it has such a big camera that if you look at a big enough region, you'll see lots of things changing. So you're going to see gas, including stars. You're going to see, maybe you'll see microlensing, I don't know, which I used to study a long time ago, which is where a small, you know,

planet or small object facets in front of a star and just changes its brightness by a very small amount. It's going to look at supernovae. It's going to look for all sorts of stuff that change, any transient phenomena, which has become the new sort of buzzword in a lot of astrophysics, looking for things that change. And yeah, so maybe it'll see asteroids. And I frankly don't know if it's going to be tuned enough to look for sort of the kind of Earth-killer asteroids that we really want to watch out for. Okay, so it's probably not going to, you know, settle the debate on dark matter, but this reminds me you wrote a paper in which you try to settle the debate, basically, by looking at what LIGO could do, right? Yeah, no, yes, I did write a paper, which I was

very excited about for, I'm still excited about it, but I thought it was, as usual, and people should realize this. You know, when you're writing, when you're a theorist, you get really excited and you think, wow, this is going to work. And then you work out the details, and it's never quite as exciting as you hoped, because it's hard. And if it was easy, everyone would do it, and we would have already discovered things.

But, yeah, what is kind of neat is that there's a kind of dark matter, one of my favorite kinds of dark matter called axions, that are very different than the other kinds of dark matter. They have a remarkable property if they exist. They couple to light, they couple to electromagnetism, and it's one of the ways that people are looking for detecting them directly. But they actually do something that amazed me much more, and I've written about this over a bunch of years,

is if there's a background of these, they act kind of like a classical background, like a background field, like an electric field, but they're an accident field. If they exist, then they actually cause light to get a little bit of a mass, but the mass oscillates. Oscillates so fast that on average it doesn't,

you wouldn't notice it. But Ligo measures basically, basically, more or less, it looks at two light rays that go in different directions and come back and interfere. And if the speed of one changes at a rate that's different than another, it's going to change that rate at which they interfere, even if it's a very small amount. And I've been thinking for some time of whether you might use LIGO or gravitational wave detectors to look for an oscillating photon mass, more or less, which would be a signal of these axiom backgrounds. And if they could detect the kind of axions,

that normally I, that come from solving a real problem in particle physics. Axions were invented not to be dark matter. They solved a real problem in particle physics called the strong CP problem. And it's still an outstanding problem that doesn't have any other good solution, in my opinion, other than axioms. But it turned out that if these particles exist, they could be dark matter, which made them even more interesting. But if those, but it turns out you can't detect those kind of axioms.

And the coupling rates are just too small. But people have realized, well, if axions could exist, then maybe there could be lots of particles. They're very, very light particles that couple very, very weakly. And then in string theory, of course, there's a host of such things. And so people have said, well, maybe there could be other light, so-called pseudoscalor particles. And what I did realize is that you could detect them if they're dark matter. And so while I actually don't believe they exist, I did point out,

still interesting me, with the very minor alterations, I think, that both LIGO and more importantly, Lisa, the space-based gravitational wave detect that's being proposed, if you designed it in advance with a few extra bells and whistles, it could look for these things with improving the current limits by five orders of magnitude, which is non-trivial. Again, I would be more shocked than anyone else if they actually existed, but I did point out that you could look for them, and you could look for them with detectives that people are already building and without spending a lot more money to look for them. So it's, you know, I originally told a friend of mine that I thought my original paper would be a masterpiece, but I think this is a mini piece. Okay. Well, it's going to

be more interesting bounds. Yeah, more interesting bounds. Yeah. Well, it gives the experimental something to do, which is always nice because, you know, they need things to do. Anyway, but a lot, you know, we'll see. Maybe it'll be more interesting. But I do like the fact that these, that gravitation wave detectors could be used for other things. I do like that. And that, and that you, and that you wouldn't require a lot of work to change them slightly, to give them an extra capability. And if you're going to build this, if you're going to build Lisa now, and it's a 10 or 20 year process, and you know in advance that if you put this extra little bell and whistle on there, you could do that. I hope maybe the experimentos would consider doing that. And I'd feel really good

if something I suggested affected an experiment down the road. Anyway, okay. Now, once again, Sabina is going to talk about something that flies in the face of conventional wisdom when it comes to astronomy and cosmology. And apparently, it's the fact

that on large scales, unlike everything we've always been told, and on the largest scales, the universe is the same in all directions. The cosmic wave background has exactly the same temperature in every direction. But now there's a paper that claims on large scales, there's actually an asymmetry in the universe.

So you already said it. But the reason I picked out this paper was because we already talked about this last month. And then this was about the Great Ring. And so maybe for the benefit of the reader, I should say. So there was this group somewhere in the UK around a guy, I think Klaus is his name. And so this group's been finding huge things in the universe for like, I don't know, a decade or something. I think actually somewhat longer, like the big arc and the giant ring and, you know, this big quasar group or whatever. And so with all these things, the claim is that these huge accumulations of matter are incredibly unlikely to,

happened just by chance in the standard Lambda CDM concordance model to one with dark energy and dark matter. And so what I said last month was, it'd be good if there was an independent confirmation from a different group. And so now, you know, just, you know, last week or something, out comes this paper, which basically is an independent confirmation. But so there's an asterisk that I have to explain here. So first of all, they used completely different data. It was from the DESE experiment. And they also did a different analysis. So they were not looking for the, like this is the thing that kind of, you know,

I find a little bit questionable about this other analysis, right? They're looking for particular patterns, basically. So they're looking for rings or arcs or crosses or whatever. I don't know. And there's always, if you do something like this, like the statistical significance becomes really, really hard to quantify because you have to ask like for exactly what shape did you actually look right and so the more specifically you look for something the less likely it is to find it

and and so then what's your baseline like so what was the probability of this thing whatever so this is something you can debate forever and and so now this new group they basically just looked at correlations over large distances so it's a fairly straightforward forward analysis. That said, so one thing that's remarkable about the paper, it was published in nature, like not in nature physics or nature astrophysics, in nature the journal. Yeah. Which is quite remarkable seeing that it's like a kind of a secondary analysis of the DESE data

by two people. The other thing that's interesting about it is that basically like a few days after the thing appeared, a paper appeared on the archive saying, well, this analysis is trivially wrong. Because they didn't properly calibrate the red shift or something. And so, you know, the criticism has not yet been peer reviewed. But, you know, just, well, I looked at it and I thought, well, they do have a point. So, I mean, this is not my research area. But so if that's actually true, like, this is going to be.

be hugely embarrassing for nature. Yeah. Well, yeah, well, yeah. So I basically, I want the paper to be right, but yeah, it doesn't seem to work. I want the paper to be wrong. I first of all, my first thought once again is that yes, they've discovered anomaly, but anomalies happen. And also, yeah, it's this, it's a statistics called angular distribution pairwise distance measurement, which is looking at correlations of things.

And you can do weird things. with statistics, depending on how you look at it. So I'm always, I'm always skeptical of this, especially when you look, when you have people looking specifically for something, and then you find statistically that it happened.

I do, you have to ask about selection effects. But I must admit, I mean, I'm not a fan of nature. I published a nature in the past, but I'm not a fan of nature. They have these ridiculous supposed standards and half the time it's not. Anyway, so I would like the paper

be wrong, mostly because I think nature is a pompous journal that often, anyway, it doesn't matter. But they have pretensions of greatness that often are not met. But anyway, okay, we'll see. But this is, you know, anytime there's no doubt that on the largest scales the universe is isotropic. There's no doubt about that fact. and whether you have these large-scale objects that are weird

and that have formed that you can't imagine how it formed are interesting but generally what happens is once you when it starts you can't imagine

how they can have formed and then if they're there someone will come up with a good explanation of how they formed later on and so whenever you can't imagine it is just that you haven't thought

hard enough or in this case the data the analysis could be wrong and and I don't want to And I don't want to poo-poo the astrophysics like this, but there's been lots of examples.

It's very difficult to do the statistics of these type of systems. People have measured large-scale flows that have gone away. They've measured, in the early days, they tried to measure the mass of the universe, that way using pair-wise motion of galaxies. And there's just a lot of stuff, a lot of subtle things that can come and screw up the analysis. So it's a difficult business.

And, you know, actually, you know, for the authors, I hope they're right in the sense. It's always nice to find something anomalous and weird about the universe. But anomalies usually go away, and so we'll wait and see. We'll see if next month there's another paper. You keep scouring the literature, Sabina, and finding these papers to support it. Every day, every day. Every day. It's nice to know someone is out there looking for the anomalies.

Now, so far, we've talked about physics and a lot of cosmology, but I do like to introduce other areas of science, and there's one that hit the papers a lot, and it is found it fascinating. I first heard about it in the scientific journals, and then I read about it in the New York Times. But it is kind of neat, and it has to do, of course, with biology, which is an area where lots of things are happening at the molecular level. And I remember years ago, I knew Craig Venters was a remote, was a, remarkably inventive scientists. He was one of the people who sequenced the human genome in a very different way than the government did. He was a very heretical scientist, a very interesting

guy. But he, his group, I remember, tried to say, what's the smallest system that can be alive? And they actually took small, you know, E. coli cells, you know, these small bacteria and other things, and they removed genes, and they eventually got something down to 526 genes that was still alive. They tried to ask what's the smallest system. They can be alive, and what does it mean to be alive? Well, it eats, it reproduces, it, you know, reliably, et cetera, et cetera. There's been another version of this, which actually is interesting to me, because in some sense, when I think about the origins of life, this is a more interesting question, starting with proteins and other things, can you build up something that is quote-unquote alive?

Now, cells require membranes, but membranes can form lipids, all these things form closed systems, or just membranes and liquids with lots of large molecules like proteins and other things you form these membranes. And what was noticed is if you put proteins on the surface these membranes, it causes the membranes to bend. And enough, and if you put enough proteins on the surface, you can form, not just a sphere, but if you put enough, they'll bend inward and they'll break, and you'll basically, it looks like cell reproduction. Then they said, well, okay, but if you put proteins on there and there's a super proteins, when these membranes bend inwards, they're going to trap some proteins, okay? And so this group began to say, well, how many, let's put in, let's see if you

can get something that looks like it's almost alive. So if you have enough proteins, and they said 100 different type of proteins. And they said, we're going to throw in this soup genes, and I think it's 36 genes that are necessary for DNA replication. And you just have that soup. Could you form objects that would basically, you know, just be membranes that, you know, eventually collapse and contain some proteins. And then maybe if they have enough proteins,

they'll bend in and they'll break and it'll look like they'll reproduce. But if you put enough food on the outside and you have enough bubbles of food, can the bubbles collide and can these membranes grow and look like they're eating? And they found a system, which is basically a very small system with 100 proteins and 36 genes that looks almost like it's alive. These systems reliably will, and there's pictures, they look spherical and there's a bunch of proteins in them, and they can grow by sort of colliding with other bubbles and eating some, effectively merging with those other proteins, until they get big enough and there's enough proteins in them to cause the membranes to bend inward and break apart.

And then each of these new two systems can do the same thing. And moreover, there's even something that looks like evolution. there's certain of these, you know, the type of, they're called spuds. The type of spud you form will depend on about the proteins that happens to be in the environment in which it collapses, in which it, you know, that it originally eats. And some of them have proteins that are more,

the membranes are more effective at merging with, with other membranes and other proteins. And you find out if you take a solution of all these pods and take ones where, some of the spuds are particularly good at eating, if you want to call it, or merging with other proteins. And some of the spuds aren't as good, and you put an uniform distribution in, over time, not surprisingly, you find that the ones that have grown and then separated, you know, and reproduced and then continue to grow again, eventually the system will be almost all the spuds that are more effective at eating.

So you begin to see what looks like reproduction, what looks like eating, and what looks like maybe even selective evolution in a system that isn't really alive. But gosh, it's interesting. And I can't help but think that maybe when we think about early life, you know, this has many of those characteristics. But what makes it even more for me exciting about this is that the group that's done this is basically making it open source. They're making an institute where they can teach anyone how to do this, and all sorts of groups will be able to merge their results. And there's nothing proprietary about it. They've basically opened it up to the field, and they're going to give rules on how to create these things. I mean, not rules that you have to obey, but rules that work.

And it's now, it's going to be an open source system, you know, group, community in the scientific. community that are going to be able to understand these spuds and maybe make bigger ones. And obviously, if you have a lot of groups that are exchanging information, you may be able to basically create an artificial life form. At least a life form that does things that you want it to do, that you maybe can design it to do. And it would be the first sort of from scratch designed quote unquote life form. Even if it's not quite alive, it may be able to reproduce and produce the kind of chemicals you want for vaccines or whatever else. So I find it a fact. fascinating and remarkable series of results,

and it may be the precursor to the first forms of artificial life that we might create in the world. So it's a very fascinating result. I don't know what you thought when you read it. No, I think that's very interesting. Honestly, I haven't followed this research at all. So what it brought to my mind is that there's kind of a parallel development where they're trying to develop an artificial

cell, like in a computer, by the help of artificial intelligence, which could have all kinds of uses in drug testing and also like for the study of the origin of life and so on. So I actually find this like, so it's one of the, one of the not that often discussed use of artificial intelligence, but I think it's one of the most interesting ones. Like personally, I would actually say it's more interesting than the material science stuff. that people often mention as the first thing, maybe because I know too much about material science. Yeah, so artificial cell, that could be a big thing

just from a practical point of view. You know, it opens up a whole new research area, and what I particularly like is that they're starting from scratch, saying this is interesting, and in order to make it grow, we want to basically put out the rules, make it open source, and get a community together that are working together without hiding anything. And that's the best way to do science in many cases.

And so I'm very, I find it a very interesting result, and I'm glad you think it is too, and from the point of view of AI as well. Now, I do want to close. I couldn't resist. You know, we only do six topics normally, but this is one that may, I think, I don't know if it'll win the ignoble prize,

but I, but it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, it's, taking cockroaches and doing two things to them. I'm amazed. First of all, you attach electrodes and other things to their brains and sensory organisms so you can control their motion. So you have semi-robotic cockroaches that you can control. It sounds like a, almost like a horror story. But then it's even better with a 3D printer. They've created little diving vests for these cockroaches so they can swim underwater for up to three hours. I, I, I think I've got to share this picture. I'm going to try and find it.

Oh, here it is. If I can share that, can you see the picture of the cockroach with its diving suit? Yes. Yes, this is the, and it's the world's first cockroach diving suit that actually works. So these cockroaches, you know, you actually, you don't, the cockroaches move, and what you, it seems almost horrific. What you do, but with control of these electrodes is, you know, if they're going one way, you can press a button and make them go another way. And there's a little movie in this thing where you can see the cockroaches doing it want to do. It's almost, it seems horrific to me. But the idea is somehow,

and I still don't understand, that if you can have them dive, these cockroaches can be used for search and rescue. I have not the slightest idea how cockroaches can be used for search and rescue. But the whole notion that it, you know, and it made nature communications and stuff, that that, that you can control the motion in a very weird way of cockroaches. And now, because you put a diving suit, they can actually breathe underwater for three hours. You can send the cockroaches where you want to do what you want and how they can do search and rescue.

I have not the slightest idea. But it was so weird, and the picture was so weird, I couldn't resist showing it. And so that's why I included in this a little bit of weird signs that may have a use or maybe just really weird and horrific. I'm not convinced which is the case. Probably both. I mean, so these remote controlled barks and cockroaches

and so have been a thing like for a decade or something, but they've, you know, slowly gotten better. And I think especially, you know, the Chinese are very interested in it, which raises an interesting question, right? I mean, what else can you do with these things, right? So the reason they want to use them for search and rescue is because they can, and collect data. And in areas where it's hard to get in with larger things,

like if you're thinking about earthquake rubble or something, you have a cockroach that can creep through everything. But of course, you can use them to do other things, right? So yeah, I mean, that's kind of weird. I mean, and they've also been trying to put all kinds of stuff on birds, and they've been trying to build artificial birds, birds actually. Yeah.

And at some point, we won't be able to tell, like, if these things are flying around us, there are actually real flies or real birds. Well, there was another article last week about an artificial, there is an artificial mosquito, which is all robotic, not in a minute. But I will say, actually, your point is really well taken. The other thing about cockroaches, I happen to know, because, you know, I've done a lot of work on nuclear catastrophes when I was, even before I was chairman of the board of a bulletin atomic scientist.

But one of the things about cockroaches is they have an amazing, they can take something like 10,000 times more radiation than a human being can and survive. So after nuclear war, the only thing that may be left are cockroaches. But it could be, for example, as you say, in nuclear reactor things, if you had diving bells, you could send these cockroaches into highly radioactive environments and they could at least provide data. So maybe you're right. Maybe that's a useful thing.

But the other argument that's made for using real cockroaches instead of robotic insects. If you have a robotic insect, the requirements on your AI and everything else are so much greater. But if you use biology, the cockroach already knows how to walk. It already knows how to do all that stuff. So the requirements are much less. You just have to put electrodes in that direct its motion. And therefore, it requires a lot less infrastructure than actually recreating an insect from scratch where you have to have to, you know, have to have an AI that could, you know, you have to have everything that's sensory organs and all the rest, whereas biology did it for us. So biology.

You don't have to build them. They reproduce. You just have to feed them. Yeah, exactly. Exactly. You don't have to build them. Energetically, they exist. You don't, and you don't have to put.

And that's another thing. You don't need batteries, right? Because they have their own batteries. Speaking of batteries, they eat. And we all are batteries. We store energy and we use it to move around and talk and maybe even think every now and then. And speaking of which, it was really great fun to think with you.

I always, I always enjoy that. and I learn a lot. So I hope the public did too. And once again, it's been a pure delight to talk to you, Sabina. And until the next time. Good to talk to you.