Alex Filippenko: Supernovae, Dark Energy, Aliens & the Expanding Universe | Lex Fridman Podcast #137

The following is a conversation with Alex Filippenko, an astrophysicist and professor of astronomy from Berkeley. He was a member of both the Supernova Cosmology Project and the High Z Supernova Search Team, which used observations of the extra galactic supernova to discover that the universe is accelerating and that this implies the existence of dark energy. This discovery resulted in the 2011 Nobel Prize for Physics. Outside of his groundbreaking research, he is a great science communicator and is one of the most widely admired educators in the world. I really enjoyed this conversation and am sure Alex will be back again in the future. Quick mention of each sponsor followed by some thoughts related to the episode Neuro the maker of functional sugar free gum and mints that I used to give my brain a quick caffeine boost, betterhelp and online therapy with a licensed professional masterclass online courses that I enjoy from some of the most amazing humans in history and Cash App the app I use to send money to friends. Please check out these sponsors in the description to get a discount and to support this podcast. As a side note, let me say that as we talk about in this conversation, the objects that populate the universe are both awe inspiring and terrifying in their capacity to create and to destroy us. Solar flares and asteroids lurking in the darkness of space threaten our humble, fragile existence here on Earth. In the chaos, tension, conflict and social division of 2020, it's easy to forget just how lucky we humans are to be here. And with a bit of hard work, maybe one day we'll venture out towards the stars. If you enjoy this thing, subscribe on.

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Apple Podcast, follow on Spotify, support on Patreon, or connect with me on Twitter lexfriedman. And now, here's my conversation with Alex Filippenko.

Let's start by talking about the biggest possible thing the universe. Sure Will the universe expand forever or collapse on itself?

Well, you know, that's a great question. That's one of the big questions of cosmology. And of course we have evidence that the matter density is sufficiently low that the universe will expand forever. But not only that, there's this weird repulsive effect. We call it dark energy, for want of a better term. And it appears to be accelerating the expansion of the universe. So if that continues, the universe will expand forever, but it need not necessarily continue. It could reverse sign, in which case the universe could in principle collapse at some point in the far, far future.

So in terms of investment advice, if you were to give me and then to bet all my money on one or the other. Where does your intuition currently lie?

Well, right now I would say that it would expand forever because I think that the dark energy is likely to be just quantum fluctuations of the vacuum. The vacuum zero energy state is not a state of zero energy. That is the ground state is a state of some elevated energy which has a repulsive effect to it. And that will never go away because it's not something that changes with time. So if the universe is accelerating now, it will forever continue to do so.

And yet, I mean, you so effortlessly mentioned dark energy. Do we have any understanding of what the heck that thing is?

Well, not really, but we're getting progressively better observational constraints. So, you know, different theories of what it might be predict different sorts of behavior for the evolution of the universe. And we've been measuring the evolution of the universe now, and the data appear to agree with the predictions of a constant density vacuum energy, a zero point energy. But one can't prove that that's what it is because one would have to show that the numbers, that the measured numbers agree with the predictions to an arbitrary number of decimal places. And of course, even if you've got 8, 9, 10, 12 decimal places, what if in the 13th one the measurements significantly differ from the prediction? Then the dark energy isn't this vacuum state ground state energy of the vacuum. And so then it could be some sort of a field, some sort of a new energy, a little bit like light, like electromagnetism, but very different from light that fills space. And that type of energy could in principle change in the distant future. It could become gravitationally attractive for all we know. There is a historical precedent to that, and that is that the inflation with which the universe began, when the universe was just a tiny blink of an eye, old, a trillionth of a trillionth of a trillionth of a second, you know, the universe went whoosh. It exponentially expanded, that dark energy like substance, we call it the inflaton, that which inflated the universe later decayed into more or less normal gravitationally attractive matter. So the exponential early expansion of the universe did transition to a deceleration, which then dominated the universe for about 9 billion years. And now this small amount of dark energy started causing an acceleration about 5 billion years ago. And whether that will continue or not is something that we'd like to answer, but I don't know that we will anytime soon.

So there could be this interesting field that we don't yet understand that's morphing over time, that's Changing the way the universe is expanding. I mean, it's funny that you were thinking through this rigorously like an experimentalist. Yeah, but what about like the fundamental physics of dark energy? Is there any understanding of what the heck it is? Or is, or is this the kind of the, the God of the gaps or the field of the gaps? So like there must be something there because of what we're observing.

I'm very much a person who believes that there's always a cause. You know, there's, there are no miracles of a supernatural nature. Okay. So, I mean, there are two broad categories. Either it's the vacuum zero point energy, or it's some sort of a new energy field that pervades the universe. The latter could change with time. The former, the vacuum energy, cannot. So if it turns out that it's one of these new fields, and there are many, many possibilities, they go by the name of quantum quintessence and things like that, but there are many categories of those sorts of fields. We try with data to rule them out by comparing the actual measurements with the predictions. And some have been ruled out, but many, many others remain to be tested. And the data just have to become a lot better before we can rule out most of them and become reasonably convinced that this is a vacuum energy.

So there is hypotheses for different fields with names and stuff like that?

Yeah, yeah. You know, generically quintessence, like the Aristotelian fifth essence. But there are many, many versions of quintessence. There's K essence, there's even ideas that, you know, this isn't something from within this dark energy, but rather there are a bunch of, say, bubble universes surrounding our universe. And this whole idea of the multiverse is not some crazy Mad Men type idea anymore. It's, you know, real card carrying. Physicists are seriously considering this possibility of a multiverse. And some types of multiverses could have, you know, a bunch of bubbles on the outside which gravitationally act outward on our bubble. Because gravity or gravitons, the, the quantum particle that is thought to carry gravity is, is thought to traverse the bulk, the space between these different little bubble membranes and stuff. And so it's conceivable that these other universes are pulling outward on us. That's not a favored explanation right now. But really nothing has been ruled out. No class of models has been ruled out completely. Certain examples within classes of models have been ruled out. But in general, I think we still have really a lot to learn about what's causing this Observed acceleration of the expansion of the universe, be it dark energy or some forces from the outside. Or perhaps I guess it's conceivable that and sometimes I wake up in the middle of the night screaming that dark energy, that which causes the acceleration and dark matter, that which causes galaxies and clusters of galaxies to be bound gravitationally even though there's not enough visible matter to do so. Maybe These are our 20th and 21st century Ptolemaic epicycles. So Ptolemy had a geocentric and Aristotelian view of the world. Everything goes around Earth. But in order to explain the backward motion of planets among the stars, that happens every year or two, or sometimes several times a year for Mercury and Venus, you needed the planets to go around in little circles called epicycles, which themselves then went around Earth. And in this part of the epicycle, where the planet is going in the direction opposite to the direction of the overall epicycle, it can appear in projection to be going backward among the stars, so called retrograde motion. And it was a brilliant mathematical scheme. In fact, he could have added epicycles on top of epicycles and, and reproduce the observed positions of planets to arbitrary accuracy. And this is really the beginning of what we now call Fourier analysis. Right. Any periodic function can be represented by a sum of sines and cosines of different periods, amplitudes and phases. So it could have worked arbitrarily well, but other data show that in fact Earth is going around the sun. So are dark energy and dark matter just these band aids that we now have to try to explain the data, but they're just completely wrong. That's a possibility as well. And as a scientist I have to be open to that possibility. As an open minded scientist, how do.

You put yourself in the mindset of somebody that where majority of the scientific community or majority of people believe that the Earth, everything rotates around Earth. How do you put yourself in that mindset and then take a leap to propose a model that the sun is in fact at the center of the solar system?

Sure. I mean, so that puts us back in the shoes of Copernicus, right. Five hundred years ago, where he had this philosophical preference for, for the sun being the dominant body in what we now call the solar system. The observational evidence in terms of the measured positions of planets was not better explained by the heliocentric sun centered system. It's just that Copernicus saw that the sun is the source of all our light and heat.

Oh, wow.

And he knew from other studies that it's far away. So the fact that it appears as big as the moon means it's actually way, way bigger. Because even at that time it was known that the sun is much farther away than the moon. So he just felt, wow, it's big, it's bright. What if it's the central thing? But the observed positions of planets at the time, in the early to mid 16th century under the heliocentric system was not a better match, at least not a significantly better match than Ptolemy's system, which was quite accurate and lasted 1500 years. Yeah, yeah.

That's so fascinating to think that the philosophical predispositions that you bring to the table are essential. So like you have to have a young person come along that has a weird infatuation with the sun.

Yeah.

That like almost philosophically is like, however their upbringing is, they're more ready for or whatever. The more the simpler answer is right. Oh, that's. It's kind of sad. It's sad from an individual descendant of ape perspective because then that means, like me, you as a scientist, you're stuck with whatever the heck philosophies you brought to the table. You might be almost completely unable to think outside this particular box you've built.

Right. This is why I'm saying that, you know, as an objective scientist, one needs to have an open mind to crazy sounding new ideas. And even Copernicus was very much a man of his time and dedicated his work to the Pope. He still used circular orbits. The sun was a little bit off center, it turns out, and a slightly off center circle looks like a slightly eccentric elliptical orbit. So then when Kepler in fact showed that the orbits are actually in general ellipses, not circles, the reason that he needed Tuco Brahe's really great data to show that distinction was that a slightly off centered circle is not much different from a slightly eccentric ellipse. And so there wasn't much difference between Kepler's view and Copernicus's view. And Kepler needed the better data, Tuco Brahe's data. And so that's again a great example of science and observations and experiments working together with hypotheses. And they kind of bounce off each other, they play off of each other, and you continually need more observations. And it wasn't until Galileo's work around 1610, that actual evidence for the heliocentric hypothesis emerged. It came in the form of Venus, the planet Venus, going through all of the possible phases, from new to crescent to quarter to gibbous to full to waning gibbous. Third quarter, waning crescent, and then new again, it turns out, in the Ptolemaic system, with Venus between Earth and the sun, but always roughly in the direction of the sun, you could only get the new and crescent phases of Venus, but the observations showed a full set of phases. And moreover, when Venus was gibbous or full, that meant it was on the far side of the sun. That meant it was farther from Earth than when it's crescent, so it should appear smaller. And indeed it did. So that was the nail in the coffin, in a sense. And then Galileo's other great observation was that Jupiter has moons going around it, the four Galilean satellites. And, and even though Jupiter moves through space, so too do the moons go with it. So first of all, Earth is not the only thing that has other things going around it. And secondly, Earth could be moving as Jupiter does, and things would move with it. We wouldn't fly off the surface and our moon wouldn't be left behind and all this kind of stuff. So that was a big breakthrough as well, but it wasn't as definitive, in my opinion, as the phases of Venus.

Perhaps I'm revealing my ignorance, but I didn't realize how much data they were working with.

Yeah.

So there's. So it wasn't Einstein or Freud thinking in theories, it was a lot of data and you're playing with it and seeing how to make sense of it. So it isn't just coming up with completely abstract thought experiments. Yeah, it's looking at the data.

Sure.

Astronomy.

Newton's great work, right? The Principia, it was based in part on Galileo's observations of balls rolling down inclined planes supposedly falling off the Leaning Tower of Pisa. But that's probably apocryphal in any case. You know, the Inquisition actually did, or the Roman Catholic Church did history a favor. Not that I'm condoning them, but they placed Galileo under house arrest and that gave Galileo time to publish, to assemble and publish the results of his experiments that he had done decades earlier. It's not clear he would have had time to do that had he not been under house arrest. And so Newton, of course, very much used Galileo's observations.

Let me ask the old Russian overly philosophical question about death. So we're talking about the expanding universe.

Sure.

How do you think human civilization will come to an end if we avoid the, the near term issues we're having? Will it be our sun burning out? Will it be comets? Okay, will it be. What is it? Do you think we have a shot at reaching the, the Heat death of the universe.

Yeah. So we're going to leave out the anthropogenic causes of our potential destruction, which I actually think are greater than the celestial causes.

So if we get lucky. Yeah, if we get intelligent, I don't know.

Yeah. So no way will we as humans reach the heat death of the universe. I mean, it's conceivable that machines, which I think will be our evolutionary descendants, might reach that, although even they will have less and less energy with which to work as time progresses, because eventually even the lowest mass stars burn out, although it takes them trillions of years to do so. So the point is that certainly on Earth, there are other celestial threats, existential threats, comets, exploding stars, the sun burning out. So we will definitely need to move away from our solar system to other solar systems. And then, you know, the question is, can they keep on propagating to other planetary systems sufficiently long? In our own solar system, the sun burning out is not the immediate existential threat. That'll happen in about 5 billion years when it becomes a red giant. Although I should hasten to add that within the next 1 or 2 billion years, the sun will have brightened enough that unless they're compensatory atmospheric changes, the oceans will evaporate away. And you need much less carbon dioxide for the temperatures to be maintained roughly at their present temperature. And plants wouldn't like that very much. So you can't lower the carbon dioxide content too much. So within 1 or 2 billion years, probably the oceans will evaporate away. But on a sooner timescale than that, I would say an asteroid collision leading to a potential mass extinction, or at least an extinction of complex beings such as ourselves that require quite special conditions, Unlike cockroaches and amoebas to survive. One of these civilization changing asteroids is only 1km or so in diameter and bigger. And a true mass extinction event is 10 km or larger. Now, it's true that we can find and track the orbits of asteroids that might be headed toward Earth. And if we find them 50 or 100 years before they impact us, then clever applied physicists and engineers can figure out ways to deflect them. But at some point, some comet will come in from the deep freeze of the solar system. And there we have very little warning, months to a year.

What's the deep freeze, Sergeant?

Oh, the deep freeze is sort of out beyond Neptune. There's this thing called the Kuiper Belt, and, and it consists of a bunch of, you know, dirty ice balls or icy dirt balls. It's the source of the comets that occasionally come close to the sun. And then there's an even bigger area called the scattered disk, which is sort of a big donut surrounding the solar system, way out there from which other comets come. And then there's the Oort cloud, double o r t after Jan Oort, a Dutch astrophysicist. And it's the better part of a light year away from the sun, so a good fraction of the distance to the nearest star, but that's like a trillion or 10 trillion comet like objects that occasionally get disturbed by a passing star or whatever. And most of them go flying out of the solar system, but some go toward the sun and they come in with little warning. By the time we can see them, they're only a year or two away from us. And moreover, not only is it hard to determine their trajectories sufficiently accurately to know whether they'll hit a tiny thing like Earth, but outgassing from the comet of gases, when the ices sublimate, that outgassing can change the trajectory just because of conservation of momentum, right? It's the rocket effect. Gases go out in one direction, the object moves in the other direction. And so since we can't predict how much outgassing there will be and in exactly what direction, because these things are tumbling and rotating and stuff, it's hard to predict the trajectory with sufficient accuracy to know that it will hit. And you certainly don't want to deflect a comet that would have missed, but you thought it was going to hit and end up having it hit. That would be like the ultimate Charlie Brown, you know, goat. Instead of trying to be the hero, right, he ended up being the goat.

What would you, what would you do if it seemed like in a matter of months that there is some non zero probability, maybe a high probability that there will be a collision. So from a scientific perspective, from an engineering perspective, I imagine you would actually be in the room of people deciding what to do. What. Yeah, philosophically too, it's a tough one, right?

Because if you only have a few months, that's not much time in which to deflect it. Early detection and early action are key because when it's far away, you only have to deflect it by a tiny little angle and then by the time it reaches us, the perpendicular motion is big enough to miss earth. All you need is one radius or one diameter of the earth, right? That actually means that all you would need to do is slow it down so it arrives four minutes later, or speed it up so it arrives four minutes earlier and Earth will have moved through one radius in that time. So it doesn't take much. But you can imagine if a thing is about to hit you, you have to deflect at 90 degrees or more. Right. And you don't have much time to do so. And you have to slow it down or speed it up a lot, if that's what you're trying to do to it. And so decades is sufficient time, but months is not sufficient time. So at that point, I would think the name of the game would be to try to predict where it would hit. And if it's in a heavily populated region, Try to start an orderly evacuation perhaps. But that might cause just so much panic that I'm. How would you do it with New York City or Los Angeles or something like that? Right.

I might have a different opinion a year ago. I'm a bit disheartened by, you know, in the movies there's always extreme competence from the government.

Competence, yeah, competence, right. But we expect extreme incompetence if anything, right?

Yes. No. So I'm quite disappointed. But sort of from a medical perspective, I think you're saying there in a scientific one, it's almost better to get better and better, maybe telescopes and data collection to be able to predict the movement of these things or come up with totally new technologies. You can imagine actually sending out probes out there to be able to almost have little fingers, sensors throughout our solar system to be able to detect stuff.

Well, that's right, yeah. Monitoring the asteroid belt is very important. 99% of the so called near Earth objects ultimately come from the asteroid belt. And so there we can track the trajectories. And even if there's a close encounter between two asteroids which deflects one of them toward Earth, it's unlikely to be on a collision course with Earth in the immediate future. It's more like tens of years. So that gives us time. But we would need to improve our ability to detect the objects that come in from a great distance. Unfortunately, those are, are much rarer. The comets come in. 1% of the collisions perhaps are with comets that come in without any warning. Hardly. And so that might be more like a billion or 2 billion years before one of those hits us. So maybe we have to worry about the sun getting brighter on that timescale. I mean, there's the possibility that a star will explode near us in the next couple of billion years. But over the course of the history of life on Earth, the estimates are that maybe only 1 of the mass extinctions was caused by a star blowing up, in particular a special kind called a gamma ray burst. And the, I think it's the Ordovician Silurian. Ordovician Silurian extinction 420 or so 440 million years ago that is speculated to have come from one of these particular types of exploding stars called gamma ray bursts. But even there the evidence is circumstantial. So those kinds of existential threats are reasonably rare. The greater danger I think is civilization changing events where it's a much smaller asteroid, which those are harder to detect, or a giant solar flare that shorts out the grid in all of North America. Let's say now astronomers are monitoring the Sun 247 with various satellites. And we can tell when there's a flare or a coronal mass ejection. And we can tell that in a day or two a giant bundle of energetic particles will arrive and twang the magnetic field of Earth and send all kinds of currents through long distance power lines. And that's what shorts out the transformers. And transformers are expensive and hard to replace and hard to transport and all that kind of stuff. So if we can warn the power companies and they can shut down the grid before the big bundle of particle hits, then we will have mitigated much of this. Now for a big enough bundle of particles, you can get short circuits even over small distance scales. So not everything will be saved, but at least the whole grid might not go out. So again, astronomers, I like to say, support your local astronomers. They may help someday save humanity by telling the power companies to shut down the grid. Finding the asteroid 50 or 100 years before it hits, then having clever physicists and engineers deflect it. So many of these cosmic threats, cosmic existential threats, we can actually predict and do something about or observe before they hit and do something about.

So it's terrifying to think that people would listen to this conversation. It's like when you listen to Bill Gates talk about pandemics in his TED talk a few years ago and realizing we should have supported our local astronomer more.

Well, I don't know whether it's more because as I said, I actually think human induced threats or things that occur naturally on Earth, either a natural pandemic or perhaps a bioengineering type pandemic or something like a super volcano, right? There was one event, Toba, I think it was seventy plus thousand years ago, that caused a gigantic decrease in temperatures on Earth because it sent up so much soot that it blocked the Sun Right. It's the nuclear winter type disaster scenario that some people, including Carl Sagan, talked about decades ago. But we can see in the history of volcanic eruptions even more recently in the 19th century, Tambora and other ones, you look at the record and you see rather large dips in temperature associated with massive volcanic eruptions. Well, these super volcanoes, one of which by the way exists under Yellowstone in the central U.S. i mean, it's not just one or two states, it's a gigantic region and there's controversy as to whether it's likely to blow anytime in the next hundred thousand years or so. But that would be perhaps not a mass extinction because you really need to, or perhaps not a complete existential threat because you have to get rid of sort of the very last humans for that. But at least getting rid of killing off so many humans. Truly billions and billions of humans. There have been ones tens of thousands of years ago, including this one, Toba, I think it's called, where it's estimated that the human population was down to 10,000 or 5,000 individuals, something like that. If you have a 15 degree drop in temperature over quite a short time. It's not clear that even with today's advanced technology we would be able to adequately respond, at least for the vast majority of people. Maybe some would be in these underground caves where you'd keep the president and a bunch of other important people. But the typical person is not going to be protected when. When all of agriculture is cut off. Right.

And when it could be hundreds of.

Millions or billions of people.

Yeah.

Starving to death.

Exactly. That's right. They don't all die immediately, but they use up their supplies. Or again, this electrical first of toilet paper. There you go, Dash that toilet paper, you know, or the electrical grid. I mean, imagine North America without power for a year. I mean, we've become so dependent. We're no longer the cave people. They would do just fine. Right. What do they care about the electrical grid? Right. What do they care about agriculture? They're hunters and gatherers. But we now have become so used to our way of life that the only real survivors would be those rugged individualists who live somewhere out in the forest or in a cave somewhere completely independent of anyone else.

Yeah, I've recently recommended, it's totally new to me, this kind of survivalist folks. But there's a, a few show, there's a lot of shows of those, but I saw one on Netflix and I started watching them and there's. They make a lot of sense. They, they reveal to you how dependent we are on all aspects of this beautiful systems we human have built.

Right.

And how fragile they are.

Incredibly fragile.

And this whole conversation is making me realize how lucky we are.

Oh, we're incredibly lucky. But we've set ourselves up to be very, very fragile. And we are intrinsically complex biological creatures that except for the fact that we have brains and minds with which we can try to prevent some of these things or respond to them, we as a living organism require quite a narrow set of conditions in order to survive. You know, we're not cockroaches, we're not going to survive a nuclear war.

So we're kind of. There's this beautiful dance between. We've been talking about astronomy, that astronomy, the stars like inspires everybody. And at the same time there's this pragmatic aspect that we're talking about. And so I see space exploration as the same kind of way that it's reaching out to other planets, reaching out to the stars is this really beautiful idea. But if you listen to somebody like Elon Musk, he talks about space exploration as very pragmatic, like we have to, if we, we have to be. He has this ridiculous way of sounding like an engineer about it, which is like, it's obvious we need to become a multi planetary species if we were to survive long term. So maybe both philosophically in terms of beauty and in terms of practical. What's your thoughts on space exploration, on the challenges of it, on how much we should be investing in it, and on a personal level, like how excited you are by the possibility of going to Mars, colonizing Mars and maybe going outside the solar system.

Yeah, great question. There's a lot to unpack there, of course. Sorry, sorry. Humans are by their very nature explorers, pioneers. They want to go out, climb the next mountain, see what's behind it, explore the ocean depths, explore space. This is our destiny to go out there. And of course, from a pragmatic perspective, yes, we need to plant our seeds elsewhere really, because things could go wrong here on Earth. Now some people say that's an excuse to not take care of our planet, that, well, we say we're elsewhere and so we don't have to take good care of our planet. No, we should take the best possible care of our planet. We should be cognizant of the potential impact of what we're doing. Nevertheless, it's prudent to have us be elsewhere as well. So in that regard, I actually agree with Elon that it'd be good to be on Mars. That would Be yet another place for us from which to, you know, explore further.

Would that be a good next step?

Well, that's the good. It's a good next step. I happen to disagree with him as to how quickly it will happen. Right. I mean, I think he's very optimistic. Now you need visionary people like Elon to get people going and to inspire them. I mean, look at the success he's had with multiple companies. So maybe he gives this very optimistic timeline in order to be inspirational to those who are going out there. And certainly his success with the rocket that is reusable because it landed upright and all that, I mean, that's a game changer. It's sort of like every time you flew from San Francisco to Los Angeles, you discard the airplane. Right. I mean, that's crazy. Right. So that's a game changer. But nevertheless, the timescale over which he thinks that there could be a real thriving colony on Mars I think is far too optimistic.

What's the biggest challenges to you? One is just getting rockets, not rockets, but people out there. And two is the colonization.

Yeah.

Do you have thoughts about this challenges of this kind of prospect?

Yeah, I haven't thought about it in great detail other than recognizing that Mars is a harsh environment. You don't have much of an atmosphere there. You've got less than a percent of Earth's atmosphere. So you'd need to build some sort of a dome right away. Right. And that would take time. You need to melt the water that's in the permafrost or have canals dug from which you transport it from the polar ice caps.

You know, I was reading recently in terms of like, what's the most efficient source of nutrition for humans that were to live on Mars? And people should look into this. But it turns out to be insects.

Insects, yeah. Yeah.

So you want.

Yeah.

You want to build giant colonies of insects.

Right.

And just be eating.

Insects have a lot of protein.

Right. A lot of protein. And they're easy to grow. Like, you can think of them as farming.

Right. But it's not going to be easy. As easy as growing a whole plot of potatoes like in the movie the Martian, you know, or something. Right. It's not going to be that easy. But there's this thin atmosphere. It's got the wrong composition. It's mostly carbon dioxide. There are these violent dust storms. The temperatures are generally cold. You'd need to do a lot of things. You need to terraform it basically in order to make it nicely livable without some dome surrounding you, and if you insist on a dome, well that's not going to house that many people. Right?

You know, well, so let's look, let's look briefly then, you know, we're looking for a new apartment to move into. Right? So let's look outside the solar system. Do you think you've, you've spoken about exoplanets as well? Do you think there's possible homes out there for us outside of our solar system?

There are lots and lots of homes, possible homes. I mean there, there's a planetary system around nearly every star you see in the sky, and one in five of those is thought to have a roughly Earth like planet.

And that's a relatively new. Yeah, it's a new discovery.

I mean the Kepler satellite, which was flying around above Earth's atmosphere, was able to monitor the brightness of stars with exquisite detail. And they could detect planets crossing the line of sight between us and the star, thereby dimming its light for a short time, ever so slightly. And it's amazing. So there are now thousands and thousands of these exoplanet candidates, of which something like 90% are probably genuine exoplanets. And you have to remember that only about 1% of stars have their planetary system oriented edge on to your line of sight, which is what you need for this transit method to work. Right. Some arbitrary angle won't work and certainly perpendicular to your line of sight that is in the plane of the sky won't work because the planet is orbiting the star and never crossing your line of sight. So the fact that they found planets orbiting about 1% of the stars that they looked at in this field of 150 plus thousand stars, they found planets around 1%. You then multiply by the inverse of 1%, which is, you know, right. 1% is about how many what the fraction of the, of the stars that have their planetary system oriented the right way. And that already back of the envelope calculation tells you that of order, 50 to 100% of all stars have planets. Okay. And then they've been finding these earth like planets, etc. Etc. So there are many potential homes. The problem is getting there. Okay, so then a typical bright star, Sirius, the brightest star in the sky, maybe not a typical bright star, but it's 8.7 light years away. Okay, so that means the light took 8.7 years to reach us. We're seeing it as it was about nine years ago. Okay, so then you ask how long would a rocket take to get there at Earth's escape speed, which is 11 kilometers per second. And it turns out it's about a quarter of a million years now. That's 10,000 generations. Okay, let's say a generation of humans is 25 years, right? So you'd need this colony of people that is able to sustain itself, all their food, all their waste disposal, all their water, all the recycling of everything for 10,000 generations. They have to commit themselves to living on this vehicle. Right. I just don't see it happening. What I see potentially happening if we avoid self destruction, intentional or unintentional here on Earth, is that machines will do it. Robots that can essentially hibernate, they don't need to do much of anything for a long, long time as they're traveling. And moreover, if some energetic charged particles, some cosmic ray hits the circuitry, it fixes itself, right? Machines can do this. I mean, it's a form of artificial intelligence. You just tell the thing, fix yourself basically, and then when you land on the planet, start producing copies of yourself initially from materials that perhaps sent, or you just have a bunch of copies there. And then they set up factories with which to do this. I mean, this is very, very futuristic. But it's much more feasible, I think, than sending flesh and blood over interstellar distances a quarter of a million years to even the nearest stars. You're subject to all kinds of charged particles and radiation. You have to shield yourself really well. That's by the way, one of the problems of going to Mars is that it's not a three day journey like going to the moon. You're out there the better part of a year or two and you're exposed to lots of radiation, which typically doesn't do well with living tissue. Right. Or living tissue doesn't do well with the radiation.

And the hope is that the robots, the AI systems, might be able to carry the fire of consciousness. Whatever makes us humans. Yeah, like a little drop of whatever makes us human. So special. Not to be too poetic about it, but.

No, but I like being poetic about it because it's a, it's an amazing question, you know, is there something beyond just the bits, the ones and zeros to us? You know, it's an interesting question. I like to think that there, there isn't anything and that how beautiful it is that our thoughts, our emotions, our feelings, our compassion all come from these ones and zeros. Right? That to me actually is a beautiful thought. And the idea that machines silicon based life effectively could be our natural evolutionary descendants, not from a DNA perspective, but they are our creations. And they then carry on that to me is a beautiful thought in some ways, but others find it to be a horrific thought.

That's exciting to you. It is exciting to me as well because to me, from a purely an engineering perspective, it's, I believe it's impossible to create like whatever systems we create that take over the world. It's impossible for me to imagine that those systems will not carry some aspect of what makes humans beautiful.

Yeah.

So like a lot of people have these kind of paperclip ideas that will build machines that are cold inside, or philosophers call them zombies there that naturally the systems that will out compete us on this earth will be cold and non, non conscious, not capable of all the human emotions and empathy and compassion and love and hate, the beautiful mix of what makes us human. But to me, intelligence requires all of that. So in order to out compete humans, you better be good at the full picture.

Right. So artificial general intelligence, in my view, encompasses a lot of these attributes that you just talked about. Yeah, I tend to curiosity, inquisitiveness, you know. Right.

It might look very different than us humans, but it will have some of the magic.

But it'll also be much more able to survive the onslaught of existential threats that either we bring upon ourselves or don't anticipate here on Earth, or that occasionally come from beyond. And there's nothing much we can do about a supernova explosion that just suddenly goes off. And really, if we want to move to other planets outside our solar system, I think realistically that's a much better option than thinking that humans will actually make these gigantic journeys. And then I do this calculation for my class. Einstein's special theory of relativity says that you can do it in a short amount of time in your own frame of reference. If you go close to the speed of light, but then you bring in E equals MC squared, and you figure out how much energy it takes to get you accelerated to close enough to the speed of light to make the time scales short in your own frame of reference. And the amount of energy is just unfathomable. Right. We can do it at the Large Hadron Collider. With protons, we can accelerate them to 99.9999% of the speed of light. But that's just a proton. We're gazillions of protons. Okay. And that doesn't even count the rocket that would carry us, the payload. And you would need to either store the fuel in the rocket, which then requires even more mass for the rocket, or collect fuel along the way, which is difficult so getting close to the speed of light, I think is not an option either, other than for a little tiny thing like Yuri Milner and others are thinking about this Starshot project where they'll send a little tiny camera to Alpha Centauri 4.2 light years away. They'll zip past it, take a picture of the exoplanets that we know orbit that three or more star system and say hello real. Say hello real quickly and then send the images back to us. Okay, so that's a tiny little thing, right? Maybe you can accelerate that to, they're hoping, 20% of the speed of light with a whole bunch of high powered lasers aimed at it. It's not clear that other countries will allow us to do that, by the way, but that's a very forward looking thought. I mean, I very much support the idea, but there's a big difference between sending a little tiny camera and sending a payload of people with equipment that could then mine the resources on the exoplanet that they reach and then go forth and multiply. Right.

Well, let's talk about the big galactic things and how we might be able to leverage them to travel fast. I know this is a little bit science fiction, but, you know, ideas of wormholes and the ideas at the edge of black holes that reveal to us that this fabric of space time is, could be messed with.

Yeah, perhaps.

Is that at all an interesting thing for you? I mean, in looking out at the universe and studying it as you have, is that also a possible, like a dream for you, that we might be able to find clues how we can actually use it to improve our transportation?

It's an interesting thought. I'm certainly excited by the potential physics that suggest this kind of faster than light travel effectively, or, you know, cutting the distance to make it very, very short through a wormhole or something like that.

Possible? No.

Well, you know, Colony, not very imaginative, but based on today's knowledge of physics, which I realize, you know, people have gone down that rabbit hole and, you know, a century ago, Lord Kelvin, one of the greatest physicists of all time, said that all of fundamental physics is done. The rest is just engineering. And guess what? Then came special relativity, quantum physics, general relativity, how wrong he was. So let me not be another Lord Kelvin. On the other hand, I think we know a lot more now about what we know and what we don't know and what the physical limitations are. And to me, most of these schemes, if not all of them, seem very far fetched, if not impossible. So travel through wormholes for Example, it appears that for a non rotating black hole, that's just a complete no go, because the singularity is a point like singularity, and you have to reach it to traverse the wormhole and you get squished by the singularity. Okay? Now for a rotating black hole, it turns out there is a way to pass through the event horizon, the boundary of the black hole, and avoid the singularity and go out the other side or even traverse the donut hole like singularity. In the case of a rotating black hole, it's a ring singularity. So there's actually two theoretical ways you could get through a rotating black hole or a charged black hole. Not that we expect charged black holes to exist in nature because they would quickly bring in the opposite charge so as to neutralize themselves. But rotating black holes, definitely reality. We now have good evidence for them. Do they have traversable wormholes? Probably not, because it's still the case that when you go in, you go in with so much energy that it either squeezes the wormhole shut or you encounter a whole bunch of incoming and outgoing energy that vaporizes you. It's called the mass inflation instability. And it just sort of vaporizes you nevertheless. You know, you could imagine, well, you're in some vapor form, but if you make it through, maybe you could, you know, reform or something.

So it's still information?

Yeah, it's still information. It's scrambled information. But there's a way maybe of bringing it back. Right. But then the thing that really bothers me is that as soon as you have this possibility of traversal of a wormhole, you have to come to grips with a fundamental problem, and that is that you could come back to your universe at a time prior to your leaving, and you could essentially prevent your grandparents from ever meeting. This is called the grandfather paradox. Right. And if they never met, and if your parents were never born, and if you were never born, how would you have made the journey? To prevent the history from allowing you to exist? Right. It's a violation of causality, of cause and effect. Now, physicists such as myself take causality violation very, very seriously. We've never seen it.

You took a stand.

Yeah, I mean, you know, I mean, it's one of these right, Back to the Future type movies, right? And you have to work things out in such a way that you don't mess things up. Right. Some people say that, well, you come back to the universe, but you come back in such a way that you cannot affect your journey. But then, I mean, that seems kind of Contrived to me, or some say that you end up in a different universe. And this also goes into the many different types of the multiverse hypothesis and the many worlds interpretation and all that. But again, then it's not the universe from which you left, right. And you don't come back to the universe from which you left. And so you're not really going back in time to the same universe, and you're not even going forward in time necessarily then to the same universe. Right. You're ending up in some other universe. So what have you achieved?

Right, You've traveled. You traveled, you ended up in a different place than you started in more ways than one.

Yeah. And then there's this idea, the Alcubierre drive, where you warp space time in front of you so as to greatly reduce the distance and you can expand the space time behind you. So you're sort of riding a wave through space time. But the problem I see with that, beyond the practical difficulties and the energy requirements. And by the way, how do you get out of this bubble through which you're riding this wave of space time? Miguel Alcubierre acknowledged all these things. He said this is purely theoretical, fanciful and all that. But a fundamental problem I see is that you'd have to get to those places in front of you so as to change the shape of space time, so as to make the journey quickly. But to get there, you got there in the normal way at a speed considerably less than that of light. So in a sense, you haven't saved any time. Right. You might as well have just taken that journey and gotten to where you were going.

Yeah, there's.

Right. What have you done? It's not like you snap your fingers and say, okay, let that space there be compressed and then I'll make it over to Alpha Centauri in the next month. You can't snap your fingers and do that.

Yeah, but yeah, we're sort of assuming that we can fix all the biological stuff that requires for humans to persist through that whole process. Because ultimately it might boil down to just extending the life of the, of the human in some form, whether it's through the robot, through the digital form, or through. Or actually just figuring out genetically how to live forever. Because that's right, that journey that you mentioned, the long journey, might be different if somehow our understanding of genetics, of our understanding of our own biology. Yeah, all that kind of stuff would. That's another trajectory.

If you could put us into some sort of suspended animation, you know, hibernation or something. And greatly increase the lifetime. And so these 10,000 generations I talked about, what do they care? It's just one generation and they're asleep. Okay, long nap. So then you can do it. It's still not easy, right? Because you've got some big old huge colony. And that just through E equals MC squared, right? That's a lot of mass. That's a lot of stuff to accelerate. The Newtonian kinetic energy is gigantic. Right? So you're still not home free, but at least you're not trying to do it in a short amount of clock time, right? Which if you look at E equals MC squared requires truly unfathomable amounts of energy because the energy is sort of, it's your rest mass M naught C squared divided by the square root of 1 minus V squared over C squared. And if your listeners want to just sort of stick into their pocket calculator as V over C approaches 1, that one over the square root of 1 minus V squared over C squared approaches infinity. So if you wanted to do it in zero time, you'd need an infinite amount of energy. That's basically why you can't reach, let alone exceed the speed of light. For a particle moving through a pre existing space, it's that it takes an infinite amount of energy to do so.

So that's talking about us going somewhere. What about. One of the things that inspires a lot of folks, including myself, is the possibility that there's other that this conversation is happening on another planet in different forms with intelligent life forms. Well, first we could start as a cosmologist. What's your intuition about whether there is or isn't intelligent life out there outside of our own?

Yeah, I would say I'm one of the pessimists in that. I don't necessarily think that we're the only ones in the observable universe which goes out roughly 14 billion years in light travel time and more like 46 billion years when you take into account the expansion of space. So the diameter of our observable universe is something like 90, 92 billion light years. That encompasses 100 billion to a trillion galaxies with 100 billion stars each. So now you're talking about something like 10 to the 22nd, 10 to the 23rd power stars and roughly an equal number of Earth like planets and so on. So there, there may well be other intelligent life.

But your sense is our galaxy is not teeming with life.

Yeah, our galaxy, our Milky Way galaxy with several hundred billion stars and potentially habitable planets is not teeming with intelligent Life intelligent? Yeah, I wouldn't. Well, I'll get to the primitive life, the bacteria, in a moment. But you know, we may well be the only ones in our Milky Way galaxy, at most a handful, I'd say. But I'd probably side with the school of thought that suggests we're the only ones in our own galaxy just because I don't see human intelligence as being a natural evolutionary path for life. I mean, there's a number of arguments. First of all, there's been more than 10 billion species of life on Earth in its history. Nothing has approached our level of intelligence and mechanical ability and curiosity. Whales and dolphins appear to be reasonably intelligent, but there's no evidence that they can think abstract thoughts that they're curious about the world. They certainly can't build machines with which to study the world. So that's one argument. Secondly, we came about as early hominids only 4 or 5 million years ago, and as Homo sapiens only about a quarter of a million years ago. So for the vast majority of the history of life on Earth, an intelligent alien zipping by Earth would have said there's nothing particularly intelligent or mechanically able on Earth. Okay, yeah. Thirdly, it's not clear that our intelligence is a long term evolutionary advantage. Now it's clear that in the Last hundred years, 200 years, we've improved the lives of millions, hundreds of millions of people, but at the risk of potentially destroying ourselves, either intentionally or unintentionally or through neglect, as we discussed before.

That's a really interesting point, which is it's possible that there, a huge amount of intelligent civilizations have been born even through our galaxy, but they live very briefly and they die.

Flashbulbs in the night. That brings me to the fourth, the fourth issue, and that is the, you know, the Fermi Paradox. If they're common, where the hell are they? You know, notwithstanding the various UFO reports in Roswell and all that, they just don't meet the bar. They don't clear the bar of scientific, scientific evidence, in my opinion. Okay, so, you know, there's, there's no clear evidence that they've ever visited us on Earth here. So, and you know, SETI has been, now, the Search for Extraterrestrial Intelligence has been scanning the skies. And true, we've only looked a couple of hundred light years out, and that's a tiny fraction of the whole galaxy, a tiny fraction of these hundred billion plus stars. Nevertheless, you know, if the galaxy were teeming with life, especially intelligent life, you'd expect some of it to have been far more advanced than ours. Okay. There's no special. Nothing special about when the industrial revolution started on Earth. Right. The chemical evolution of our galaxy was such that billions of years ago, nuclear processing and stars had built up clouds of gas after their explosion that were rich enough in heavy elements to have formed Earth like planets even billions of years ago. So there could be civilizations that are billions of years ahead of ours. And if you look at the exponential growth of technology among Homo sapiens in the last couple of hundred years, and you just project that forward, I mean, there's no telling what they could have achieved even in 1,000 or 10,000 years, let alone a million or 10 million or a billion years. And if they reach this capability of interstellar travel and colonization, then you can show that within 10 million years, or certainly 100 million years, you can populate the whole galaxy. All right, so then you don't have to have tried to detect them beyond 100 or a thousand light years. They would already be here.

Do you think, as a thought experiment, do you think it's possible that they are already here? But we humans are so human centric that we're just not like our conception of what intelligent life looks like. We don't want to acknowledge it. What if trees.

Right, right, right, yeah.

Like, okay, I guess in a form of a question, do you think we'll actually detect intelligent life if it came to visit us?

Yeah, I mean, it's like, you know, you're an ant crawling around on a sidewalk somewhere and do you notice the humans wandering around?

Exactly.

And the Empire State Building and, you know, rocket ships flying to the moon and all that kind of stuff. Right. It's conceivable that we haven't detected it and that we're so primitive compared to them that we're just not able to do so.

Like, if you look at dark energy, maybe. Yeah, maybe we call it as the field.

It's just that my own feeling is that in science now, through observations and experiments, we've measured so many things, and basically we understand a lot of stuff. Okay.

Fabric of reality.

Yeah, the fabric of reality we understand quite well. And there are a few little things like dark matter and dark energy that may be some sign of some super intelligence, but I doubt it. Okay. Why would some superintelligence be holding clusters of galaxies together? Why would they be responsible for accelerating the expansion of the universe? So the point is that through science and applied science and engineering, we understand so much now that I'm not saying we know everything, but we know A hell of a lot. Okay. And so it's not like there are lots of mysteries flying around there that are completely outside our level of, of, of exploration or understanding.

Yeah. You know, from, I would say from, from the mystery perspective, it seems like the mystery of our own, like cognition and consciousness, is much grander than like the degrees of freedom of possible explanations for what the heck is going on is much greater there than in the, in the physics.

Exactly.

Of the observer.

How the brain works, how did life arise? Yeah, that's big, big questions. But they to me don't indicate the existence of an alien or something. I mean, unless we are the aliens. You know, we could have been contamination from some rocket ship that hit here a long, long time ago and all evidence of it has been destroyed. But again, that alien would have started out somewhere. They're not here watching us right now. Right. They're not among us. And so though there are potential explanations for the Fermi paradox, and one of them that I kind of like is that the truly intelligent creatures are those that decided not to colonize the whole galaxy because they'd quickly run out of room there because it's exponential. Right. You send a probe to a planet, it makes two copies. They go out, they make two copies each and it's an exponential. Right. They quickly colonize the whole galaxy, but then the distance to the next galaxy, the next big one like Andromeda, that's two and a half million light years. That's a much grander scale now. Right. And so it also could be that the reason they survived this long is that they got over this tendency that may well exist among sufficiently intelligent creatures, this tendency for aggression and self destruction. Right. If they bypass that, and that may be one of the great filters, if there are more than one, then they may not be a type of creature that feels the need to go and say, oh, there's a nice looking planet and there's a bunch of ants on it, let's go squish them and colonize it. No. It could even be the kind of Star Trek like Prime Directive where you go and explore worlds but you don't interfere in any way. Right.

And, and also we call it exploration is beautiful and everything, but there is underlying this desire to explore is a desire to conquer.

Yeah.

I mean, if we're just being really honest about right now, for us it is.

Right.

And you're saying it's possible to separate, but I would venture to say that you wouldn't, that those are coupled. So I could, I could imagine a Civilization that lives on for billions of years, that just stays on. Its like, figures out the minimal effort way of just peacefully existing. It's like a monastery.

Yeah. And it limits itself.

Yeah, it limits itself.

You know, it's, it's planted its seeds in a number of places, so it's not vulnerable to a single point failure. Right. Supernova going off near one of these stars or something, or an asteroid or a comet coming in from the Oort cloud equivalent of that planetary system, and without warning, you know, thrashing them to bits. So they've got their seeds in a bunch of places, but they chose not to colonize the galaxy and they also choose not to interfere with this incredibly prevalent primitive organism, Homo sapiens. Right.

Or they, this is like a, they enjoy. This is like a TV show for them. Yeah, it's like a reality.

It's like a TV show. Right.

So they just tuned in.

Right. So those are possible explanations. Yet I think that to me, the most likely explanation for the Ferry Me paradox is that they really are very, very rare. And, you know, Carl Sagan estimated 100,000 of them. If there's that many, some of them would have been way ahead of us. And, and I think we would have seen them by now if there were a handful, maybe they're there. But at that point, you're right on this dividing line between being a pessimist and an optimist and what are the odds for that? Right. If you look at all the things that had to go right for us.

Yeah.

And then, you know, getting back to something you said earlier, let's discuss, you know, primitive life. Yeah, that could be the thing that's difficult to achieve. Just getting the random molecules together to a point where they start self replicating and evolving and becoming better and all that. That's an inordinately difficult thing, I think, though I'm not some molecular cell biologist, but just it's the usual argument. You're wandering around in the Sahara Desert and you stumble across a watch, is your initial response. Oh, a bunch of sand grains just came together randomly and formed this watch. No, you, you think that something formed it or it came from some simpler structure that then became more complex. All right. It didn't just form. Well, even the simplest life is a very, very complex structure. Even the simplest prokaryotic cells, not to mention eukaryotic cells, although that transition may have been the so called great Filter as well. Maybe the cells without a nucleus are relatively easy to form. And then the big next step is where you have a Nucleus, which then provides a lot of energy, which allows the cell to become much, much more complex and so on. Interestingly, going from eukaryotic cells, single cells, to multicellular organisms does not appear to be, at least on Earth, one of these great filters, because there's evidence that it happened dozens of times independently on Earth. So by a really great filter, something that happens very, very rarely. I mean that we had to get through an obstacle that is just incredibly rare to get through.

And one of the really exciting scientific things is that that particular point is something that we might be able to discover even in our lifetimes that find life elsewhere like Europa or be able to see.

That would be bad news, right? Because if we find lots of pretty advanced life, that would suggest, and especially if we found some defunct fossilized civilization or something somewhere else that would be of bacteria.

You mean, what's that defunct civilization of primitive life.

I'm sorry, I switched gears there. If we, if we found some intelligent, or rather even trilobites, right, and stuff elsewhere, that would be bad news for us because that would mean that the Great Filter is ahead of us, because it would mean that lots of things have gotten roughly to our level. But given the Fermi paradox, if you accept that the Fermi paradox means that there's no one else out there, you don't necessarily have to accept that, but if you accept that it means that no one else is out there. And yet there are lots of things we found that are at or roughly at our level, that means that the Great Filter is ahead of us and that bodes poorly for our long term future.

It's funny, you said you started by saying you're a little bit on the pessimistic side, but it's funny because we're doing this kind of dance between pessimism and optimism because I'm not sure if us being alone in the observable universe as intelligent beings is pessimistic.

Well, it's good news in a sense for us because it means that we made it through.

Oh, right.

See, if we're the only ones and there are such great filters, maybe more than one formation of life might be one of them. Formation of eukaryotic, that is, with a nucleus, cells be another development of human like intelligence might be another.

Right?

There might be several such filters and we were the lucky ones. And then people say, well then that means you're putting yourself into a special perspective. And every time we've done that, we've been wrong. And yeah, yeah, I know all those arguments but it still could be the case that there's one of us at least per galaxy or per 10 or 100 or a thousand galaxies. And we're sitting here having this conversation because we exist. And so there's an observational selection effect there. Right. Just because we're special doesn't mean that we shouldn't have these conversations about whether or not we're special. Right? Yeah.

So that's exciting. That's optimistic.

So that's the optimistic part, that if we don't find other intelligent life there, it might mean that we're the ones that made it.

And in general, outside the Great Filter and so on, you know, it's not obvious that the Stephen Hawking thing, which is. It's not obvious that life out there is going to be kind to us.

Oh, yeah. So, you know, I knew Hawking, and I greatly respect his. His scientific work and in particular the early work on the unification of general theory of relativity and quantum physics to two great pillars of modern physics, you know, Hawking radiation and all that fantastic work. If you were alive, he should have been a recipient of this year's physics Nobel Prize, which was for the discovery of black holes, and also by Roger Penrose for the theoretical work showing that given a star that's massive enough, you basically can't avoid having a black hole. Anyway, Hawking, fantastic. I tip my hat to him. May he rest in peace.

That would have been a heck of a Nobel Prize for black holes.

Yeah, yeah, yeah.

Heck of a good group.

But. But going back to what he said, that we shouldn't be broadcasting our presence to others there, I actually disagree with him, respectfully, because first of all, we've been unintentionally broadcasting our presence for a hundred years, since the development of radio and tv. Okay. Secondly, any alien that has the capability of coming here and squashing us either already knows about us and, you know, doesn't care because we're just like little ants. And when there are ants in your kitchen, you tend to squash them. But if there are ants on the sidewalk and you're walking by, do you feel some great conviction that you have to squash any of them? No. You generally don't. Right. We're irrelevant to them. All they need to do is keep an eye on us to see whether we're approaching the kind of technological capability and know about them and have intentions of attacking them, and then they can squash us. Right. You know, they could have done it long ago. Yeah. They'll do it if they want to. Whether we advertise Our presence or not is irrelevant. So I really think that that's not a huge existential threat.

So this is a good place to bring up a difficult topic. You mentioned they would be paying attention to. To us to see if we come up with any crazy technology. There's folks who have reported UFO sightings. There's actually have recently found out. There's websites that track this, the date, the data of these reportings. And there's millions of them in the past several decades, so seven decades and so on, that they've been recorded. And the ufologist community, as they refer to themselves, you know, one of the ideas that I find compelling from an alien perspective, that they kind of started showing up ever since we figured out how to build nuclear weapons, that we should.

Coincidence.

Yeah. So, I mean, you know, if I was an alien, I would start showing up then as well. Just.

Well, why not just observe us from afar?

No, I know, right? I would figure out. But that's why I'm always keeping a distance and staying blurry.

Right. Very pixelated.

Very pixelated. There is something in the human condition that a cognition that wants to see, wants to believe beautiful things. And some are terrifying, some are exciting goats. Bigfoot is a big fascination for folks.

Yeah.

And UFO sightings, I think, falls into that. There's people that look at lights in the night sky. And I mean, there's. It's kind of a downer to think in a skeptical sense. To think, though, that's just a light.

Yeah.

You want to feel like there's something magical there.

Sure.

I mean, I felt that first when my dad. My dad's a physicist, when he first told me about ball lightning.

Yeah.

When I was like a little kid.

Very weird.

Very, like. Yeah. Weird physical phenomena. And he said his intuition was. Tell me this, as a little kid, like, I really like math. His intuition was, whoever figures out ball lightning will get a Nobel Prize. Like, he. I think that was a side comment he gave me. And I. I decided there when I was like 5 years old or whatever. Yeah, I'm going to win a Nobel Prize for figuring out Bollinger. That was like one of the first sort of sparks of the scientific mindset. Those mysteries, they capture your imagination. I think when I speak to people that report UFOs, that's that fire. That's what I see, that excitement.

And I understand that.

But what. What do we do with that? Because there's hundreds of thousands, if not millions, and then the scientific community, you're like the perfect person. You have an awesome Einstein. What do we do with those reports? It's. Most of the scientific community kind of rolls their eyes and dismisses it. Is it possible that a tiny percent of those folks saw something that's worth deeply investigating?

Sure, we should investigate it. It's just one of these things where, you know, they've not brought us a hunk of kryptonite or something like that. Right. They haven't brought us actual, tangible physical evidence with which experiments can be done in laboratories. It's anecdotal evidence. The photographs are in some cases, in most cases, I would say, quite ambiguous.

I don't know what to think about. So David Fravor is the first person. He's a Navy pilot commander, and there's a bunch of them, but he's sort of one of the most legit pilots and people I've ever met.

Right.

The fact that he saw something weird, he doesn't know what the heck it is. Yeah, we saw something weird. I mean, I don't know what to do with that. And one on the psychological side. So I'm pretty confident he saw what he says he saw, which he's not providing. He's saying it's something weird.

Right.

One of the interesting psychological things that worries me is that everybody in the Navy, Everybody in the U.S. government, everybody in the scientific community just kind of like, pretended that nothing happened. That kind of instinct, that's what makes me believe if aliens show up, we would all, like, just ignore their presence. That's what bothered me that you don't. You don't investigate it more carefully and use this opportunity to inspire the world like so. In terms of kryptonite, I think the conspiracy theory folks say that whenever there is some good hard evidence that scientists would be excited about the U, there's this kind of conspiracy that I don't like because it's ultimately negative, that the US government will somehow hide the good evidence.

Yeah.

To. To protect it. Of course, there's some legitimacy to it because you want to protect military secrets, all that kind of stuff. But, yeah, I, I don't know. I don't know what to do with this beautiful mess because I think millions of people are inspired by UFOs, right. And it feels like an opportunity to inspire people about science.

So I would say, you know, as Carl Sagan used to say, extraordinary claims require extraordinary evidence. Right. I've quoted him a number of times. We would welcome such evidence. On the other hand, a lot of the things that are seen or perhaps even hidden from us, you could imagine for military purposes, surveillance Purposes the US Government doesn't want us to know. Or maybe some of these pilots saw Soviet or Israeli or whatever satellites. Right. A lot of the. Or some of the crashes that have occurred were later found to be weather balloons or whatever. When there are more conventional explanations, science tends to stay away from the sensational ones. And so it may be that someone else's calling in life is to investigate these phenomena, and I welcome that. As a scientist, I don't categorically actually deny the possibility that ships of some sort could have visited us, because as I said earlier, at slow speeds, there's no problem in reaching other stars. In fact, our Voyager and Pioneer spacecraft, in a few million years are going to be in the vicinity of. Of different stars. We can even calculate which ones they're going to be in the vicinity of. Right. So there's nothing that breaks any laws of physics if you do it slowly. But that's different. You know, just having Voyager or Pioneer fly by some star. That's different from having active aliens altering the trajectory of their vehicle in real time, spying on us, and then either zipping back to their home planet or sending signals that tell them about us, because they are likely many years, many light years away, and they're not going to have broken that barrier as well. Okay. Right. So I just, you know, go ahead, study them. Great. You know, for some young kid who wants to do it, it might be their calling, and that's how they might find meaning in their lives, is to be the scientist who really explores these things. I chose not to because at a very young age, I found the evidence to the degree that I investigated it to be really quite unconvincing. And I had other things that I wanted to do, But I don't categorically deny the possibility, and I think it should be investigated.

Yeah, I mean, this is one of Those phenomena that 99.9% of people are almost definitely. There's conventional explanations, and then there's like, mysterious things that probably have explanations that are a little bit more complicated.

Yeah, it's.

But there's not enough to work with. I tend to believe that if aliens showed up, there will be plenty of evidence for scientists to study. Yeah, like, and exactly as you said, a Voyager type of spacecraft, I could see sort of some kind of. Kind of a dumb thing, almost like a sensor to, like, probing, like, statistically speaking, flying by, maybe lands. Maybe there's some kind of robot type of thingies that just like, move around and so on.

Yeah.

Like in ways that we don't understand. But, but I feel like, well, I feel like there'll be plenty of hard, hard to dismiss evidence. And I also, especially this year, believe that the US government is not sufficiently competent, given the huge amount of evidence that will be revealed from this kind of thing, to conceal all of it.

Right.

At least in modern times you can say maybe decades ago, but in modern times. But, you know, the people I speak to and the reason I bring it up is because, because so many people write to me, they're inspired by it.

By the way, I wanted to comment on something you said earlier. Yeah. I had said that I'm sort of a pessimist in that I think there are very few other intelligent, mechanically able creatures out there. But then I said, yes, in a sense I'm an optimist, as you pointed out, because it means that we made it through the Great Filter. Right. I meant originally that I'm a pessimist in that I'm pessimistic about the possibility that there are many, many of us.

Out there, mathematically speaking, in the Drake Equation.

Exactly. Right, right. But. But it may mean a good thing for our ultimate survival. Right. So I'm glad you caught me on that.

Yeah, I definitely agree with you. It is ultimately an optimistic state.

But anyway, I think, you know, UFO research is interesting and I guess one of the reasons I've not been terribly convinced is that I think there are some scientists who are investigating this and they've not found any clear evidence. Now, I must admit I have not looked through the literature to convince myself that there are many scientists doing systematic studies of these various reports. So I can't say for sure that there's a critical mass of them. It's just that you never get these reports from hardcore scientists. That's other thing. And astronomers, you know, what do we do? We spend our time studying the heavens and you'd think we'd be the ones that are most likely, aside from pilots perhaps, at seeing weird things in the sky and we just never do. Of the unexplained UFO type nature.

Yeah, I definitely, I try to keep an open mind, but for people who listen, it's actually really difficult for scientists.