John Michael Godier Dr. Avi Loeb welcome back to the program now. Dr You worked extensively in black holes and the theories regarding them and now we actually have a picture a picture of sorts of satutarius a star. Avi Loeb Thanks for having me.
John Michael Godier What's your reaction to that. What what did you think upon seeing the image of the central supermassive black hole of the milky way. Avi Loeb Well, in fact, two decades ago I worked on the the expected image that we might get and in fact I am brought to the center for astrophysics at Harvard. The the person who funded. Founded the event horizon telescope so we started the work from there and I I was involved in the early stages of the project promoting it and making theoretical predictions for what they might find and we actually wrote a paper with my postdoctoral fellow Ayprodrick. Ah. Arguing that it's not the black hole at the center
of the milky way that the only one that we should look at it. There is another one in the galaxy m 8 7 and we wrote the first paper talking about it and forecasting the image of that black hole and it ended up being the first one. Ah, of which an image was ah publicized m ad 7 is a galaxy that is about and 2000 times far than the black hole at the center of the milky way galaxy but the the black hole there is 1500 times. Ah, bigger ah, in mass so you end up with an image of the silhouette which has roughly the same angle on the sky and you can detect both of them and ah so I'm you know I'm really pleased to see those images the face of the black hole in the middle of the milky way galaxy and. Now that we have that image. It can be a tourist destination and you might ask? Why
would the tourists go there? Well um, if you go to the location for example of the photon ring. It's really an amazing place because you can look. Forward and see your back because light makes a full circle around the black hole. Also if you get close to the horizon of the black hole. Ah time is
ticking more slowly there so you can outlive. Ah. Your friends on earth in a sense because time is progressing more slowly there. Ah and then also you know I can imagine that we we can give discounted tickets to ah string theories. To go there because if they get close to the singularity of the black hole they can test their ideas and of course these will be 1 way. Tickets. John Michael Godier Do you think that black holes because of that reason that Alien scientists could go there and start testing string theory and things like that. Do you think that we're looking. We're barking up the wrong tree perhaps by looking
for techno signatures when we should really be looking at black Holes. For any evidence of Alien civilizations because that's where they would locate their physics Labs. Perhaps. 06:50.58 Avi Loeb No I mean if you think about about it in practical terms. The only benefit of being close to a black hole is that you can throw your trash to the black hole and get clean energy in return and the efficiency of converting trash into clean energy.
Is the highest that you can imagine because ah about 10% of the rest mass can be converted to radiation in the vicinity of a black hole. So that's ah, a practical way of getting ah a lot for for what you deposit there and um. So. Other than that, it's actually quite a risky environment because objects move very fast near a black hole and that can create a lot of friction and damage to anything that you possess and moreover very often these environments light up with. Matter that is falling into the black hole shines very brightly because it hits up and so it's a risky environment. In fact, we wrote a scientific paper saying that if the black hole at the center of the milky way. Sagitar says star were were to be fed. Ah, right now. It's.
Starving and that's why we can look through the galaxy and and get very close to imaging the shadow of the black hole. But if it were fed I mean it's actually underfed by almost a billion times then than what it can be fed with and if it was fed a billion times more then. Ah, all the habitable planets out to a distance of a few thousand lighters from it could have been ah, sterilized. There is ultraviolet radiation there there are x-rays emitted by such a black hole when when it a creates a lot of gas and and and therefore it. You know life is not easy close to it and so I would actually cautionshen civilization from getting too close to a black hole. We are located the sun is located twenty Four Thousand light years away from the center of the milkyan that's ah, a relatively safe environment.
And and it might not be by chance and you know if we were much closer than episodes of and the black hole at the center lighting up could have sterilized the earth. John Michael Godier Now people have brought that up before then said that the orientation of of sagitary as a star might actually be pointed at us the Relativistic Jet might be pointed at us does this new image clear that up I mean what is the orientation of it towards us and. If something if it started creating a bunch of matter could that be a problem if the Relativistic jet is pointed towards us. Avi Loeb Yeah, so first of all, we don't know that this black hole produces jets usually jets are produced by black holes that are spinning and so there are 2 questions here whether the black hole is spinning and the second is. Whether the orientation of the pole the the direction of the spin is towards us because that's usually the direction of the jet and then um, the the event horizon telescope team. Um. Produced a lot of
computer models trying to simulate the image that was observed and they claim that among you know the many models that they looked at the ones that appeared most consistent with the data. Ah correspond to. And nearly face on situation where you know if there is a jet we we are in its direction so to speak and also ah to a situation where the black hole is spinning and I think. This conclusion may not be right because and ah for 1 thing the chance of the black hole to be pointing at us the jet pointing at us is really small and because that would mean that it's you know. Pemppendicular to the direction of the disc of the milk way.
So if you imagine material from the disc of the milky way falling into the black hole, then the black hole should be spinning in the plane of the milky way galaxy but what you need here is that since we are in the plane you need it. To be spinning exactly penmendicular to that which seems really strange and um, the other thing is we analyzed with a postdoctoral fellow jacomo fragian we analyzed the orbits of the stars in the vicinity of the black hole and. And they seem to lie in 2 preferred planes. The the stars near the black hole and just like the planets moving around the sun. There seem to be 2 planes from where they they orbit and um and. We showed that if the black hole was spinning then Einstein's theory of general relativity would have basically blurred those planes you wouldn't you wouldn't see 2 distinct planes because on a relatively short time. Scale. The stars would.
Avi Loeb Shift away from the original birth plane that they were at so we were able to argue that the spin of the black hole must be small and that is opposite to the inference from the event horizon telescope image and so my guess and Mark my words is that. Something in the models that they were considering or using did not include all the physics. You know they didn't have all the ingredients that they should have had to produce ah proper images of the black hole and. Obviously to generate the image you need to assume something about how matter is falling into the black hole how it moves around it. How you produce the radiation. There are a lot of uncertainties in on these issues and they must have assumed or explored a certain range of parameters. But my guess is. They they they are missing something
and that's why they reach those conclusions which do not seem to be very likely to me. John Michael Godier And now the formation of a non-rotating black hole. So you you know? of course you have a a star collapsing in on itself and standard black hole formation that if that star's rotating. It's going to rotate faster
and faster as it Collapses. So How do you create. A non-rotating black hole. Avi Loeb Oh yeah, so first thing to keep in mind is this black hole at the center of the milky way is 4000000 times the mass of the sun. Okay, so it's 4000000 it weighs as much as four million Suns so it it was not the result of the collapse of of a massive star. Um. But it was a result of and infa of gas into a seed black hole
or the mergers of many black holes now if you imagine mergers or even ah accretion of gas you know through episodes. So. At some point in time. There is a cloud of gas falling into the center and it's orbiting in ah in some plane. Okay, some preferred direction. It will give the black hole spin according to the direction that it's orbiting in and then if there is another cloud of gas coming in a different direction. It will. Give a different and spin orientation and so you keep adding these episodes and they add up if they add up randomly you will end up with no spin and in the same way if you were to merge black holes suppose each black hole has some spin but but they arrive to the. Merger point at you know at random then you would average out the spins of
all the building blocks that you put together to make the final black hole so it will average up out to 0 so 1 way 1 simple way of getting very low spin is. If you were to start with building blocks each of which were randomly oriented and then you put them together and they cancel out so you end up with a very small spin on the other hand the way to build a very high spin is if instead of having many building blocks. For example, you have 1 major episode of. Growth for the black hole and you always maintain the same orientation of the matter that falls into the black hole so you keep adding and rotation in the same direction and then you get a final black hole that is spinning very fast. So it all depends on the history of how this black hole came to exist. And in the context of
galaxies like the milky way. You would think that you know there were many episodes of small building blocks coming together and that's why a very low spin is is quite likely. John Michael Godier And is there any effect and I would imagine. There's not but you would know and I would not that is there an effect on a
spinning black hole and the behavior of its event Horizon. In other words, if you imagine a star that's spinning very rapidly. It will sort of crush you know and and. Long gate can that happen to a black hole or or does just the laws of gravity prevent it from being anything except an identical event Horizon to a non-spinning black hole. 26:04.34 Avi Loeb Oh no, no, we we know the solution to Einstein's equations of general relativity in the case of a black hole with any arbitrary spin and this is called the care solution. It. After a physicist with a last- name keer that ah lived in New Zealand and um um, and and that allows for any arbitrary spin and now of course the event horizon the location of and and the shape of the event horizon depends on the spin. So. Just to give
you the 2 extremes when you have a non-spinning black called 0 spin that is the solution that Schwartel Carr schwartel derived back in nineteen Fifteen a few months after Albert Einstein ah came with equations einstein published his equations in November on the. November Nineteen Fifteen and then then a few months later he couldn't get ah an analytics solution to the full equations and Karl Sch watching he basically volunteered to serve in the german military. He was the director of the observatory at Potsdam at the time and about forty years old and felt very loyal to the german nation and volunteered to the military and went to the german front and and then derived the solution while being there to Einstein's equation that sent. Einstein a postscard with a solution Einstein was thrilled to to receive it and and publicize this solution and then a few months later kar schwatcher died at the front from some rare lung disease and just to illustrate the fact that if you want to. Derive the consequences of e theory you better be a pacifist than being a patriot because then you have more time to work out the solutions. So at any event Einstein was a pacifist schwartzer was a patriot and therefore einstein had more time to derive consequences of his theory later on. But at any even the the schwatz's solution is the
solution of a black hole a point mass and that's for a non-spinning black hole that has no spin and and the solution is really simple. Um, there is ah an event horizon at a distance that is twice times neuttons constant times the mass of the black hole. Divided by the speed of light squirld. Okay, and that's called the schwartzel horizon and it's spherical. It's a spherical shell around the point mass in the middle of it. There is a singularity where Einstein's theory breaks down. We don't know what happens we you need to incorporate quantum mechanics to figure out to.
Avi Loeb But what happens near the singularity because the curvature of space and time diverges there so clearly Einstein's theory doesn't have quantum mechanics. That's why it breaks down at the singularity. Um, and and we still don't have that unification of quantum mechanics and gravity. So we are still faced with that that problem. But at any event and about the um, you know, ah more than half
a century later care derived the the solution for a spinning black hole and and that's quite different in the case where the black hole is spinning fastest near the speed of light. Um. In that case, the horizon shrinks by a factor of 2 so it becomes half the and in the equatorial plane half the the schwartel rad use and then it's squashed and the the horizon is not spherical anymore. And there are lots of interesting phenomena there. Um, and that we don't have time to get into in the care case. But in principle you can extract energy from a spinning black hole by having matter near it or matter with a magnetic field. It's sort of like a flywheel that you can tap. And extract energy from so the spin of the black hole and we believe that the jets are that we see in in ah in in distant galaxies that move near the speed of light are being powered by the extraction of energy from this flywheel. Of a spinning black hole.
John Michael Godier Now 1 question about Kerr now in his ideas. There is the concept of the cur ring in a spinning black hole and where you you know you don't have a point you have a a ring and my question is now some people have advanced. The concept of maybe this is a wormhole. Maybe this leads somewhere. Do you think that has
legs or do you think it's just simply a dead end. You don't go anywhere. You just hit you just hit. You know you just add your mask to the black hole as opposed to actually going anywhere if you could get through it with some sort of exotic matter or whatever that you know. Avi Loeb Ah.
John Michael Godier People have pointed out but do you think that that it is a solution possibly that it's a rip in spacetime that happens in the center of the black hole. Avi Loeb Okay, so first Roy Kare derived his solution a year after I was born 1963 it's fifty nine years ago almost sixty years ago before that. Um. Einstein together with Nathan Rosen were wondering you know for the Schwartel solution. Ah you know what lies inside and if matter falls into it. You know
what happens to it. Can it go somewhere else. Um, and they came up with a paper that suggested some bridge that you can sort of imagine 2 schwat's solutions where if you know matter getting into one of them comes out from the other side or. And then that led to additional work on on wormholes now the situation right now is um without quantum mechanics. These wormholes cannot exist because
um, they basically snap. Ah. On a timescale that is too short for anyone to go through them for any matter to go through them. So Einstein's theory of gravity doesn't really allow it. But then if you imagine quantum mechanics being incorporated in a way that you know you make the wormhole from matter that is. Quite unusual and method that has negative pressure which we you know don't have access to. We cannot engineer such substance. But nevertheless if you imagine a substance with negative pressure I should say. Ah, we do know that the universe has such
substance. It's called dark energy which causes the accelerated expansion of the universe. But that's considered to be the energy of the vacuum and we don't know how to manipulate it to make a wormhole for example, but if you imagine that you can do that the question is do can can we imagine solutions. Involve wormholes with that made out of and material that has negative pressure and people have tried to derive such solutions their claims recently that they can have such such stable entities black wormholes that you can go through but I would say all of these are tentative claims. You know. First for the reason that we don't have in our possession. The ability to engineer such
matter with negative pressure and second because even the mathematics is not yet on a solid footing. So right now I would probably bet that you know worm so wormholes. Avi Loeb Do not exist in nature that we can't make such things but let's see I mean you know physics is only a century. The modern physics is only a century Old. We Still don't have a unified theory that Marries Quantum mechanics with Gravity. So You know there might there might be surprises in the future.
John Michael Godier Now about surprises and about the current state of where we're at. Do you think within our reasonable lifetime. We will see a unified theory that that bridges the gap between Quantum mechanics and general relativity and. Avi Loeb So here is what I learned in the about 4 decades that I practiced physics I learned that the only way for us to make real progress in our understanding of nature is by being guided by evidence by experiments and. The same should apply to how to unify quantum mechanics and gravity I mean the the thing is that very brave theorists. You know like four decades ago thought that they can just do it by pure thing pure thought and so the the most you know the most popular.
Ah, theory right? now is string theory but they thought that it would lead them along a path such that they would be able to get ah a single solution and turns out there are many possibilities and that's exactly why we need experiments. We need evidence to guide us nobody would have thought about quantum mechanics a century ago. Unless experiments told us that indeed it exists and Einstein actually had difficulties interpreting quantum mechanics he was resisting the the simple interpretation of those experiments and he was wrong. He thought that the entanglement is not real and. Ah, now we use it in devices you know quantum computers and so forth. So I mean it was clearly not intuitive to him and and nobody would have come with quantum
mechanics out of pure thought okay and just to think that we can figure out nature without doing experiments I think is very arrogant. So the the only way by which we can make progress is through experiments through evident collecting evidence nature is much more imaginative than we are so my point is we tried to to follow the path of string theory just based on pure thought for. By now four decades. We haven't yet come up with any predictions that can be tested experimentally and what are the avenues for us to make progress. Well there are 2 places in the universe where quantum gravity is needed 1 is near the big bang. You know what happened close to the beginning of
the universe back then the you know the conditions were such that both quantum mechanics and gravity were important and the second is the singularities of black holes so by getting more data on black holes. We may get closer to. Seeing things that guide us we can also get closer to the big bang by peering back in time detecting for example, gravitational waves from that time or other signatures. These are the best hopes for us to be guided and I would. Avi Loeb Basically say let's wait until we get to the point where we where we get some experimental evidence about perhaps the singularity of the big bang. All the singularities of black holes and before we get there before we have something to guide us. We might be going in the wrong directions. 49:09.50 John Michael Godier
Now Some people have pointed out that the universe and the big bang somewhat resembles a black hole in certain ways. Do you think this is superficial or do you think that's actually a a helpful direction to go in to look at it. Whether or not we live in the interior of a black hole or not. 49:43.76 Avi Loeb
Yeah, so the big bang ah was a singularity and indeed in black holes. You do have a singularity but they are of a different type the the big bang singularity was a singularity in time. There was a point in time you know we know the universe is expanding if we. Go back in time. There was a point in time where the density of matter and radiation were infinite. You just you know as the universe expands. It. It gets Rarefid. But if you go back in time. There was a point where everything diverges you know and and that's called the big bang and. And
that was a singularity in time. It was not in space because the universe started pretty much uniform very close to being uniform. We know that by looking at the cosmic microve background. We know that the conditions for example, four hundred thousand years after the big bang. The conditions were uniform throughout the universe. 1 part in 100000 you know that's a very we we measured it. We measured the small changes between 1 location in the universe and another
at that early time by observing the cosmic micro rebecon and the differences were tiny. One part in 100000 so the universe started uniform. In space to 1 part in a 0 but it had a singularity in time when you consider a black hole. It's it's exactly the opposite. In fact, the Schwatz's solution is a solution for. A stationary object an object that doesn't evolve in time you know it's it's the same at all times, but it has a singularity in space. Ah so to speak in the sense that inside the
event horizon there is a point where you know the curvature diverges and. That's probably where all the matter goes when it falls into a black hole. You know I had once a flood in in the basement at my home and I called the plumber we went down and we found that there were tree roots ah blocking this sewer and we cleared the three roots. And then it led me in those hours when we were working on that it led me to think about what happens to the matter that goes into a black hole because until then you know I was just taking it for granted that all the water in in my home is going down the drain and I don't care where it goes you know, but once it. This sewer got clogged. It reminded me that there is a place where that collects the water and so I thought okay matter falls into a black hole where does it go now you can imagine 2 things you can imagine just like the sewer case and that it goes through ah the black hole into some other space.
Avi Loeb Time you know some other universe or something another possibility is that you know this source is clogged. Okay, so there is an object that collects the matter on it and this object could have the maximum density that we can imagine. For example, it's called the plank density where you know that's the maximum density that you can achieve. Matter and you can just imagine this object ah collecting all the matter that falls onto it at the plank density and being there at the center we can't see it because it's hidden behind the event horizon and we don't know what the answer is and unless we you know we if we. Go on a journey into ah a black hole. We would figure it out but it would be too late because we would crash on on this object. We wouldn't be able to communicate it back to the rest of the world.
You know? Ah, but it's a very interesting question and and it's unsovved at the moment we don't know what the right answer is. And 1 way to figure it out is if we had a theory of quantum gravity. It would make a prediction about what happens to the matter as it falls into a black hole. John Michael Godier Now that might be an interesting tangent to go on the the environment of a black hole were you falling into it now I would imagine that your first problem as you fell into the black hole would be the accretion disc and the immense heat and x-rays everything that's coming off of that. But then Spaghheification. So even if and we're barring exotic matter here. But even if you were simply falling into the black hole. You probably wouldn't even make it to the event horizon right.
Avi Loeb Oh no, so an astronaut would make it a star like the sun would not make it in the case of sagitar say star the black or at the middle of of the galaxy. But in ma 7 just to give an example in the case of m seven even a star would get swallowed whole. Ah, once it enters to the event. It will not get ah spaghettified and the reason is that the bigger the black hole the more massive. The black hole is the less curvature of space and time there is at the horizon. So. It's really the tidal effect the you know the the same effect that the moon exerts on the oceans. That's called
tides I mean so the moon is closer to one side of the earth and it pulls on the water on the surface of earth you know and and makes you know. And and makes a bulge and and and that's the tide that we see in the ocean on the side closer to the moon. Ah, it's just the difference in the gravitational force that the moon exerts on the two sides of the earth on one side. The the force is stronger and that's why the water comes. You know more to that side. So that's called the tide and if you imagine an object like a black hole and a star like the sun getting close to it then the the black hole will will exert a tide on the star. So it will act more strongly on the side closer to the black hole. Gravitationally and if the the difference enforces between the
two sides of the star if that difference is bigger than the force that binds the star the gravitational force that the star is bound by then the star will get ripped apart and and get so. Paaghetified as you were alluding to that's called the tidal disruption of a star and for black holes like the one in the middle of the milky way such stars a star indeed a star getting within 10 times the schwartshid radius of the star of the of the black hole. The star would get. Spaghetified a star like the the sun and we calculate that roughly every hundred thousand years such a thing happens because stars get scattered to the vicinity of the black hole and you get such. You get a flare that results from the disruption of the star. But. A human an astronaut is much smaller than a star like the sun and it's not held by the force
of gravity. It's held by chemistry. So if an astronaut gets close to the horizon of sagitary say star nothing will happen to the astronaut because the size of the body of the astronaut is. Avi Loeb Only a couple of meters. You know the sun is much bigger and so the difference between the toes and the head
of the astronaut the difference in forces you know is not big enough to rip the astronaut apart except when the astronaut falls into the horizon eventually. It gets close to the singularity. Where the force is big enough and the astronaut will be ripped apart by the way I once explained that to students in the class of my in the kindergarten. My daughter invited me to to speak in front of the class and I explained this and then the teacher stopped me in the middle of the story and said. Please stop and the the kids would have nightmares if you continue so I I mean they were fascinated by this question of what happens to an astronaut now. The 1 thing
I wanted to mention is if you make the black hole even bigger than sagitar say star then if you make it like. Bigger than 100000000 times the mass of the sun instead of 4000000 the mass of sagitar se star then then even a star like the sun will not get ripped apart because the black hole is so big that there is not much curvature in its vicinity near the horizon. So so a black hole like m eighty seven. If a star comes close to it. It doesn't get ripped
apart. It can go through the horizon eventually when it gets close to the singularity. It will get ripped apart but we won't see that because it's hidden behind the horizon so tidal disruption events of stars happen only you know for relatively. Small black holes and I should say there is another risk of being near black or that 2 stars can collide with each other. This is a process that I wrote a paper with ah my student on just last year and and those collisions can be very powerful because. Tars are moving close to the speed of light near black. Also imagine you know 2 stars like the sun that happened to collide with each other. They would
release a huge amount of energy. You would have an explosion if they were to collide near black hole. John Michael Godier And colliding stars all right now this has got to be 1 of the few ways this can happen because if you if you have a merger like the coming merger with the andromeda Galaxy. It's unlikely that stars will hit each other but in ah in a black hole environment. They can. Um, is this something that could create something like a Gamma Ray burst or one of the unexplained you know, ah fast radio burst or something like that's just mysterious signals that we see in nature could this be a possible starting point for that.
Avi Loeb Yeah, well it could be with respect to gammay bursts. We think that the the 2 classes of of ah processes that lead to Gammay bursts 1 is when you have a star core collapsing the core of a massive star collapsing to make a black hole. This is a stellar mass black hole that weighs somewhere between a few times the mass of the sun up to a hundred times the mass of the sun in that case, um, the black hole can produce a jet if it's spinning and the jet will drill a hole. Through the envelope of the star and you would see it as
a gamma ray burst. So that's one and we know that this happens because we see that in the case of long duration gammay bursts that last many seconds that in fact, very often. They're followed by an exploding star. And 1 way to understand it I mean we see the afterglow. We see a supernova that takes off afterwards. But basically the the when the jet drills ah cavity through this
stellar envelope. It also releases energy and pushes the envelope to make the star explode so that is. That is one type of gammery burst sources and the second type is when you have 2 neutron stars. A neutron star is um, the core of a massive star that and ends up collapsing but doesn't make a black hole. It makes a. Star that with a density similar to the atomic nucleus but the size of a city like Boston 10 kilometers in size and then such a a star the mass of the sun a size of a city is is very compact and dense. And it's called a neutron star and we know that the supernova explosions very often lead to the formation of a neutron star. We
actually saw evidence for that in the case of 1 nearby supernova in 1987 that led to the production of neutrinos which indicate. The formation of a neutron star. So anyway, when 2 neutron stars are in a binary system in in a pair and they collide then you can get a gammay burst in a jet that is generated out of that collision and. Another interesting aspect of that collision of 2 neutron stars is that you eject some material rich in neutrons out of this collision and turns out that this is probably the the most prolific source of the heavy elements. Avi Loeb And that are called our process elements like ah gold or uranium the sources of all evil on earth you know gold if we were just close to a neutron star merger event. We would have a huge amount of gold available to us on earth. It's just that you know these collisions are so rare that gold is precious because on average there is not much gold. But if we if the earth was born
would have been born close to a site where 2 neutrons stars collided and we would have plenty of gold everywhere. Ah, and then uranium in much the same way. You know? So. Ah, if you imagine civilizations that happen to be born close to a neutron star merger event. You know they would have a lot of gold gold and potentially a lot of nuclear weapons.
John Michael Godier Just what we need a universe full of of nuclear weapons now my last question for you is to get it to get weird in regarding regards to the environment of a black hole now a star is not the only thing that can fall into a black hole. You could have a neutron star. You know, very high density object or you could have 2 stars colliding and correct me if I'm wrong I think this is the Chandra sehar limit where you you actually have something collapse into a black hole right next to the black hole because 2 stars collided can that can that occur I mean and can we detect it. Avi Loeb Oh yeah, definitely? Um, so what we most easily detect is radiation and light and any such and event of the type that you mentioned is results in an explosion that the. Is very bright and actually the future is quite exciting in this context because there is the Vera Rubin observatory that was funded by the national science foundation and it will start the operations in Chile. Ah, within a year and it will monitor the sky with a three point two billion pixel camera that's remarkable.
Just think about it. Ah three point two billion pixels come back to the same point in the sky every four days so it basically scans then tar sky we would have an unprecedented ah flood of data on events that are transient in the sky we have. Never had a telescope of this size collecting so much data. Um, and that would allow us to find a lot of explosions in the universe and presumably some of the type that you just described and I very much look forward now.
The question is how do we catalog them and. Now we have artificial intelligence so we can train you know the the old way of looking at Transientence was for fritzwiki to and look for a supernova explosions and and give them names you know and so individuals would see. A source of light in the sky that didn't exist the night before or something like that and even amateur astronomers. You know the and the supernova ninety eighty seven was discovered by an amateur astronomer. So um, the the modern way of doing it is to rely on. Ai. Scientists you know artificial intelligence scientists that would go through the pipeline of you know the the data that comes through the pipeline of ah the verra rubin observatory it's called the the legacy survey of space and time lssd and we'll basically search for interesting transients and and then of course the astronomers. Will have to make sense of that data and I very much look forward to that. That's
what makes astronomy exciting and we might find a lot of things that we haven't noticed before. John Michael Godier Now looking for transient events and that brings up the Galileo project. Um I noticed that you recently inaugurated your first instruments in the search for uipp on the roof of Harvard can you give us an overview of. Avi Loeb Yeah, so ah, we are putting together the first telescope system and I should say the weather is pretty bad in Massachusetts though there was never a major astronomical discovery made from the roof of the harvard college observatory even though there are some. John Michael Godier What you built.
Avi Loeb Telescoppes there that date back one hundred and seventy years um so the only reason we are doing it. There. Well first of all I I work at harvardard university okay, and and the funding of the project is coming from my research fund but we're doing it just to make sure that. The system works. Okay, so that's the first system we're testing it. We're making sure that everything works to our satisfaction and that's a convenient place to put it together and it includes um, ah cameras in the infrared and invisible light that are monitoring the sky all the time. Basically taking a video of the sky and also um a passive radio. Ah sensor um, basically a radar passive
radar system that looks for reflected radio waves from objects in the sky and. The data will and also an audio system I should mention that as well and all of the data will be fed into a computer system that will have software to analyze it and try to identify the objects that we see in the sky and tell us whether they are birds. Or maybe drones or maybe airplanes or anything that else and of course if we see something that doesn't quite fall into categories that we can understand easily that would be intriguing and this is the first system that we want to.
Basically make sure works according to our specifications and then hopefully by August we will have it done with data and demonstrate that it works. We plan to have the first in-person conference of the gallo project where we will look at that. Those results and then plan ahead. The question is where to put that system so that it will start getting real data of interest and we will have to select a site for it and then we will make copies of that system and put them in and in different locations and. The number of copies we make will depend on the funding that the project has so at the moment we have funding for at least a few such copies and then I should say another exciting thing that is going on is ah back in 2019 I asked my student to let. To look at the catalog of government data on meteors because um I asked him to check if any of the meteors there indicates an object that came from outside the solar system and. Avi Loeb Ah, we looked at the fastest moving objects and found that the second fastest was actually unbound to the sun very clearly moving at sixty kilometers per second outside the solar system and then we wrote a paper about it. But then the reviewers of the paper said we don't believe the government we don't.
They don't provide us with the full full access to the data with the uncertainties in the data and therefore the paper should not be published and I try to work with colleagues that have access to the actual classified data and so that they would make a statement behind. The national security fence saying that our conclusions you know whether our conclusions are robust or not and actually just and last month there was a letter that was publicized from ah the us space command under the department of defense. From the Pentagon ah to Nasa stating that they confirm that our conclusion that this meteor came from outside the solar system is correct at the 99.999
confidence. Okay, so that's an example of the government coming. To the help of science and confirming what we concluded with my student Amir Sirraj back in 2019 and now the next step is to go and scoop the fragments from that meteor on the ocean floor near Papua New Guinea and we are currently planning the expedition to do that because that would be the first time that we can put our hands on material from an object. You know that is half a meter in size that came from outside the solar system that would be very exciting and from the. Ah, the government did 1 more thing they released data on the fireball the the light that was emitted when this object burned in the lower atmosphere and analyzing this light curve led us to conclude that the object was very tough. It was tougher than an iron meteorite it but tougher than iron.
Because it burned it disintegrated only in the lower atmosphere of the earth and so that makes it very intriguing. It was moving really fast twice as fast compared to stars near the sun and that makes it rare in that regard an outlier. Ah, less than 5% of all stars moved that fast as this object was moving relative to the so system and then ah moreover it was tougher than iron or similar to iron and so that only 5% of all the space rocks.
Avi Loeb Are iron meteorites. The rest are stony meteorites and so this object is clearly an outlier It's the first object that burned up that was identified to come from outside the solar system. Actually it was found almost four years before omua mua was discovered. And so we are planning to scoop its fragments from the ocean floor and see what it was made of and my of course interest is to figure out whether it was an iron meteorite or maybe artificial in origin. John Michael Godier Now How can you? how close can you constrain where to look in other words, you know you can see the track of the meteor and you can work out about where it you know would have fallen which I actually recently spoke to him here about this that it's probably in the ocean. And so how do you constrain down exactly where to drag a magnet basically to try to you know recover some material from it.
Avi Loeb Um, so based on the Dod data on the fireball and based on acoustic data that we have we can try and triangulate where it may land and may have landed and ah we can. Now the 1 thing to keep in mind is when a meteor explodes in the lower atmosphere then you end up with a spray of fragments and sort of like iron rain. You know if you were to use an umbrella. It wouldn't you know, protect you because these are. Iron droplets that are you know ° hot you know and they would make a hole in your umbrella but imagine them spraying on the ocean surface. There would be a lot of steam as a result of that and then eventually they would land on the ocean floor but there would be some large.
Avi Loeb Um, you know over which they're they're being sprayed and it's not just one point and so we plan to scoop a relatively wide area of the order of ten kilometers in size or even more and then. Search for these tiny droplets. It's not an easy task but it was done before. John Michael Godier I it was definitely done before because the meteoritticist hhnineinger would actually drive around with a a truck back in the the 40 s around the canyon diablo crater the meteor crater in Arizona the very famous huge 1 and pick up this. Iron rain that would come from the the object that that hit and you would actually get these these tiny droplets with a magnet. So there's this has legs because you're just doing
it in the ocean and you know if it's iron. It'll pick it up. But. Avi Loeb Um, right? yeah. John Michael Godier What happens if a don't pick anything up and you know you're in the right area. Um, and you have to look for a you know something that won't attract to a magnet. You know, big piece of Tungsten or something weird. It seems to me that that would be if it was an artificial object. That it wouldn't be attracted to a magnet right? and. Avi Loeb Well, we will use a camera as well to survey the floor and see what's there so we will not rely just on the magnet.
So yeah, we are working right now on the details and I must say that. Ah, you know deciding about the equipment is 1 thing um deciding about the timing is a second and the third is the funding and I'm very optimistic on on all fronts. As of now I cannot. Give you all the details because they're not finalized, but there is excitement and ah to me you know, even though I often get seasick on a ship I would never give up the opportunity to actually witness ah and put my hands on. Um, the the material that came from a big object that came from outside the solar system because think about it to visit another star. Even the nearest star proxima centauri if we were to use chemical rockets. It would take us 50000 years roughly the time that elapsed. Since the first
humans left Africa okay, and you just think about the journey. It's really it takes a huge amount of time to go places. So if it takes so much time to go to your neighbor's yard then you better, check your own yard for material that came from your neighbor. Which is pretty much what we are doing.
John Michael Godier And just the isotope data alone of being able to get a group of samples from elsewhere in the galaxy and look at the isotope data would tell us all sorts of things about protoplanetary discs and everything else. So Just just the natural aspect. Of looking at material of Interstellar origin is just astonishing the the geology. Avi Loeb Yeah, to connect it to we can connect it to what we were discussing before because if for example, the point of origin was closed to a neutron star merger. You know you will find a lot of gold on this thing. Ah so um. Even if you imagine natural object the abundances of heavy elements may not be the same as in the solar system and especially our processed elements created for example by the collision of 2 neutron stars could be different because it all depends on the distance to the nearest such collision and. We don't know what the birthplace was of this object. So in general,
you know we tend to think that you know we live in our home and we see things around us and we see the members of our family. These are the rocks that we have found in the solar system and we tend to think all families are alike. And therefore by by looking at our family members. We pretty much understand how other people behave and how you know how they look and so forth. But guess
what if you were to go to the street you will see people that are very different than your family members. Okay. Um, and so my lesson from that is you know it's different to explore the real world compared to your virtual reality of the imaginary world where you imagine that you've seen everything already and of course it could also be a shock because you know. My daughters when they were young. They stayed at home and they thought that they're the smartest in the world and of course that was consistent because they with the data that they received because they compared themselves to the family members and they were the smartest but then when they went to the kindergarten suddenly they saw kids that might be smarter than they are and. I think we might face a similar shock The first time we find an object from an exoterrestrial civilization. You know we think of you know, just think about finding iphone 30 ah you know in so embedded in in a meteor.
John Michael Godier Now if we were to find such an artifact within our star system with us for our atmosphere with us wouldn't that statistically speaking suggest that. The universe is absolutely loaded to the hilt with Alien Civilizations and. Avi Loeb Well, it wouldn't necessarily say that there are lots of civilizations. It could say that there is one that was very prolific right? So think about ah you know humans? Okay, so it's possible that. Much of our Dna was contributed by a female and a male that had a lot of kids. You know there could have been a lot of other females and males that didn't mate as much. Ah and as a result you know we're dominated by those very prolific ones. Um, so in much the same way if you had 1 civilization that was extremely ambitious.
They didn't have just 1 Elon Musk planning to go to Mars but they had a million ah scientists and engineers that really wanted to go places not just to the next planet but actually very far away. If they were very ambitious. They could have produced self-replicating probes that would go places and reproduce and then they would dominate the milky way galaxy but it's only one such ambitious species. You don't need many. John Michael Godier Now coming to earth people often make the argument that well they wouldn't be interested in us and I've always disagreed with this argument because you know people will say well what interest do we have in an antil. Well we have specialists in Antils. On earth we have scientists that spend their careers studying ants so it would seem to me that the reason that they would come here to observe us is clear where another occurrence of life and they want to collect data on us. Do you think that the the motivation. Of an alien civilization to come here would simply be science and studying us.
Avi Loeb Yeah, well, you know what they had in mind when they created this equipment that might visit us is 1 matter but you can ask another question you know and I don't know what they had in mind and I don't you know I I'm completely agnostic about that. Because it's very difficult to guess the intentions. You know what people have in mind when you try to deal with people. It's really difficult to trust the intentions of people so and people are things that we know about they just imagine another.
Culture and other civilization. It's really difficult to forecast what they have in mind. So I don't want because the number of possibilities is so vast that I don't want to bet on one of them but another related question is you know? Ah, what should we be proud of ourself. Um. You know because very often we tell ourselves. Oh yeah, we are the pinnacle of creation. You know that we are so smart we produce technology science and so forth and I think this is very misguided and because um, you know, ah. We are doing terrible things. You know we're going
to wars. We're destroying the planet. We are not necessarily the most intelligent you can imagine you know and so um, you know in the dating app of the galaxy the interstellar dating app if we were to put our images. We wouldn't be the most popular civilization I wouldn't think I would like to date humans. Okay I would much I can imagine much more attractive dates. Okay, that are interested in knowledge that are not fighting each other because of their ego.
You know I can imagine things like that and by the way we are producing them. They are called Ai systems and I think eventually if ai systems take take control of the way science is done. We would be better off because they might not have an attachment to their ego if they see something that looks. Weird in the sky they would not behave like experts that worked on rocks their entire lives. They would not say everything in the sky must be a rock you know or a natural thing. They would be open minded. They would say oh look this is really unusual. This
doesn't look like a rock. What is it and. These are you know these ai astronauts that are not Ai yeah scientists that are not that attached to their ego might operate much better. They would gain knowledge better than humans do so altogether you know I'm not entirely proud of what we are doing and I think there is room for improvement and.
Avi Loeb That that would be my message that let's let's be better. Okay, and another example is you know we sent out new horizons this mission that went to pluto and is now exiting the solar system and we put the box with the ashes of clyumbo the scientists who discovered ah Pluto. On that mission and you know if that spacecraft collides with in a billionaires collides with an exoplanet like the earth and becomes a meteor and lands on the bottom of the ocean on that exoplanet. And you have astronomers there that say oh wow, let's check this out and they scoop the ocean floor and they find this box with the ashes of clyumbao and then they say to themselves. Oh this seems to be some burned up material relic of of a human what they realized there must be a human but. It makes very little sense because those humans wanted to commemorate someone and they destroyed all the genetic information about that someone by burning up the Dna of that person and putting it in a box to commemorate that person that makes little sense.
We don't want to have anything to do with these humans. They would tell themselves because. They seem to be quite aggressive why burn up the information about a person that you want to commemorate that makes 0 sense and then send it to space. You know that's what we've done and that was done by by our most sophisticated science agency Nasa that sent the the equipment. So again
I'm not very proud. And you know, many many people think about sending images of humans to space sending music to space all kinds of things that we feel proud of you know I would be much more modest you know I would like to learn more about others or than a. Ah, show off about us. John Michael Godier I I have to I have to admit being a science fiction author I was just compelled to start thinking about the idea of millions of clyde tumball clones attacking earth all wearing bolo ties. Um, now I have a listener question. Avi Loeb But by the way I should just tell you that I raised this point about clytumba with the principal investigator of the new horizon's mission who is a member of the gallillo project.
His name is Alan Stern and I said why didn't you try to send a stem cell. John Michael Godier Um. Avi Loeb Or an electronic you know, ah version of the Dna of cly tambo and he said it would have been a bureaucratic nightmare at Nasa much easier to send the ashes. John Michael Godier I and I'm I'm in cly tombboud died years Ago. So I'm sure he was cremated long ago now and a listener question. Um, in regards to the future of Humanity. Do You think that a great filter lies Ahead. Or do you think we're past it. Avi Loeb Well, that's a very good question and you know it really depends on how intelligently we behave. Okay, so we have control of our future in principle. Um,
and you know the different types of futures that you can imagine. There is a future that. Where we just and like thelma and louise you know we drive off the cliff because we've never witnessed our demise. Okay, we've never witnessed a situation where we destroy the conditions on on earth such that we won't be able to survive. We've never witnessed that and therefore we drive the car
off the cliff assuming nothing bad will happen. We keep arguing with each other about politics while the car is flying up into the you know over the cliff and then we fall down so that's one future where we keep. Relying on the past but in the past we never had the ability to and basically inflict wounds that would kill us and now we have those abilities so we cannot learn from experience. We have to be intelligent enough to figure out the consequences of our actions. And we may not be that intelligent. We may go into wars with each other. We may argue politically you know without noticing that we are you know heading in you know in the direction of that cliff. The other possibility is that once we get close to a catastrophe.
We would really get serious about it. We'd say okay, forget about the the rivalries between nations. Forget about showing off that you know one person is smarter than the other one person is more powerful than the other forget about this because all of us will die. There is a global threat here. Let's work together and I should say you know the virus
covid nineteen was not a good ah indication because even when it was global. There was no, there wasn't full cooperation between all nations on earth and you can see the consequences of that you know. Um, so you know now there is lockdown in Shanghai in China but if they were to realize the consequences for them as a result of their citizens living the country living Wuhan and going to milan in italy early on in the pandemic. They wouldn't. Have allowed that and they would have cooperated given all the information they have to the international communities such that scientists will be able to cope with a threat. Okay, but there wasn't cooperation early on
and as a result it comes to haunt us as as a civilization because it's a global threat. But. Avi Loeb Of course the virus. You know it kills a fraction of the population. But most of us survive and so it's not an extinction event but the the lesson from that is you know that we should cooperate on matters that are global and if we are intelligent enough. We will do that you know. The dinosaurs sixty six million years ago they were very proud of themselves they ate
grass until a huge rock the size of Manhattan Island hit the ground and tarnished their ego tree now we are smarter than that we build telescopes we can alert. Everyone that there is a giant rock heading towards earth and do something about it. So that's an example where science can help us prevent. We can deflect this rock prevent a catastrophe but we should do it on all fronts. Not just regarding rocks heading our way and if we are intelligent enough. We might do that.
John Michael Godier 1 ho
2022-05-21