Why The Universe May Be Full Of Alien Civilizations Featuring Dr. Avi Loeb

have you ever had a Eureka moment a sudden feeling of clarity were something that previously didn't make sense suddenly did or how about an idea so compelling that it hits you like an asteroid impact and you aren't quite certain how it happened the word Eureka comes from the ancient Greek word Eureka though they probably wouldn't have pronounced it that way it loosely means I found it and it's most famously associated with Archimedes Archimedes was an interesting guy he supposedly proclaimed the word as he stepped into a bathtub and noticed that the level of the water rose as he sank down into it his eureka moment was realizing that the water his body displaced must correlate with the volume of the section of his body that was submerged this solved a huge problem plaguing the science of the time humans could now determine that the volume of an object could be calculated by how much water the object displaced without destroying it thusly the volume of irregularly shaped objects such as gold and silver jewelry could now be established at least in principle this would ultimately lead to methods of determining how pure gold and silver objects actually were during a time when they were quite literally money or the kings and queens crowns but yelling Eureka wasn't enough for Archimedes it said he ran to the streets of his home city of Syracuse and Sicily still naked from his attempt at a bath excitedly telling everyone he could about his discovery whether that old account is true is for the historians to debate but from Archimedes bathtub to Newton's apple the idea of serendipity yielding new ideas and science when they are least expected is an alluring one when one has idle time for the brain to work its magic without distraction such as during a shower and great things can happen but this aspect of serendipity through seemingly mundane acts of life hasn't actually changed over the ages it's still very much there welcome to event horizon with John Michael Gautier joining John on today's program is theoretical physicist dr. avi Loeb the Frank Bieber jr. professor of science at Harvard University he is the founding director of Harvard's black hole initiative and also serves on the advisory committee for the breakthrough starshot initiative in 2012 Time magazine selected Loeb as one of the 25 most influential people in space professor Loeb welcome to the program my pleasure now I had read in a recent interview with you that you do a lot of your thinking during snowstorms when Harvard is closed tell us about that well that's part of the story most of the time I get my ideas when I go to the shower in the morning it turns out that this is the kind of environment that allows me to think freely with no interruptions and there was a Dutch television crew that came to interview me and I told them that I get many of my ideas in the shower and they decided to take a photograph to film the shower and then they asked me to wear a robe and run to my desk and they wanted to document that the problem is that you know you can't really document the way that ideas come forward there was a previous person that lived in my house and used the same shower and he the same he used the same shed the many many of the places that I spaces that I use now he ate in the same kitchen slept in the same bedroom but with very different outcomes and so ideas come to me because of the thinking about the universe the just the way babies come out of the bellies of pregnant mothers a mind becomes fertile when there is freedom to venture without traditional the confines of traditional thinking without the burden of practical concerns and so I get these these periods of time when when nobody bothers me I I'm currently the chair of the astronomy department at Harvard and the director of two centers there and on a routine basis people come to me and ask for help on various routine issues and just being able to escape from that to take a vacation from those daily routines allow me to think creatively because these routines are in a way an antique pregnancy pill they involve the burdens of life consumed at the time with practical concerns and under such circumstances ideas are scarce but fortunately I have those periods of time when I can think for myself one of those that you referred to was a time when there was a big snowstorm and how it was closed and I could think for a day without needing to teach that day I could think about the distant future of the universe what will happen you know when the universe ages by another factor of a hundred and all the galaxies that we see nowadays will run out of our horizon we won't be able to see them anymore will there will be no evidence for the big bang and so how can we then figure out if the Big Bang took place or not experimentally and this bothered me because there will be these text books telling us that there was a big bang but we won't be able to verify that because there won't be any galaxies visible to us the universe is accelerating its expansion and galaxies will will run out of our sight and at that point the question is will science turn into a religion in the sense that there will be books telling us a story without us being able to verify the validity of these stories and so I thought about it and realized that in fact our own galaxy the Milky Way is expelling stars all the time and those stars are coming from the center of the Milky Way when a pair of stars gets too close to the black hole it gets ripped apart and one star comes closer to the central black hole of the Milky Way the other one gets ejected at a very high speed such that it can escape the Milky Way and so I realize that those stars that are escaping our own galaxy can serve as light sources and that tells tell us about the expansion of the universe just like galaxies are telling us today so instead of Hubble looking at galaxies we will be able to look at stars receding away from our galaxy in the distant future and that could be a way of learning about the expansion of the universe then so in the far future cosmology on some level would still be possible it would be possible as long as stars exist and turns out that the Sun is not a typical star the stars that are most abundant are about a 10 15 minutes of the Sun and in fact the nearest star to us other than the Sun is a Proxima Centauri it has 12% of the mass of the Sun and it would live for trillions of years so these most abundant low mass stars are the longest lead stars and they do that because they burn their fuel very slowly and they can live up to about 10 trillion years a thousand times longer than the Sun and once the Sun will die or even before that we will presumably need to move to another planet around another star and those dwarf stars would be good targets because we know that at least some of them have habitable planets planets in at the right distance to have liquid water on their surface in fact Proxima Centauri has such a planet that is 20 times closer than the earth is from the Sun and has a surface temperature of about room temperature we don't know if it has liquid water there because we don't know if there is any water on it but that's one possible target my daughter by the way said that if we ever contemplate going there she would like to have two houses on this planet because turns out that this planet is so close to the star that it's tidally locked it always shows the same face to the start so there is a permanent day side in a permanent night side and so she would like to have one house in the permanent night side where she would sleep and then a second house in the permanent Sunset Strip that separates the day from the night side where she will have a permanent sunset and that's where she will go for vacation so so yeah tiny event these low mass stars are very long-lived they live for 10 trillion years and beyond once the universe ages beyond that that's roughly a thousand times more than the current age of the universe but once the universe ages beyond that point there wouldn't be any stars around stars I mean the stars will basically die at that point and but it doesn't mean the end of civilization because in principle we can by then you know when there is plenty of time we will be able to sustain our heat through nuclear reactor through some some artificial means that could outlive the the even the longest-lived starves now the low mass red dwarf type stars that live so long these are not great candidates for developing life of their own because early on they have a tendency or at least some of them have a tendency to be violent that's right but they do make as far as human colonization and escaping the Sun they do make attractive targets there but what are what is the chances of some sort of simple life developing on a planet around a red dwarf and also going with that what are the possibilities of like ice shell moons like Europa also possibly being abodes of life around red dwarfs well these are excellent questions so the first question that I wrote a few papers about is if these low mass stars outlive the Sun why don't we find ourselves next one of them and since it's not the most abundant stars why don't we find as far up next one of them in the future that's the most likely place to be in why do we find ourselves next to the Sun at the present time and it may well be that the environments next to them are not so hospitable for life so one aspect is indeed that they flare a lot and in fact Proxima Centuri had a huge flare that would have killed most forms of life on earth if we were exposed to it and the second aspect is that the habitable zone near a low-mass star because such a star is so faint the habitable zone is closer in proximity the planet next to Proxima Centauri is 20 times closer to the star than we are from the Sun and as a result it's susceptible to a very strong pressure from the wind coming from the star and in that wind Canon principals trick the atmosphere of the planet because it's so powerful and so if there is no atmosphere there is no life because life as we know it requires liquid water and if you take water eyes and you just warm it in vacuum it turns into gas it doesn't turn into liquid you need an external pressure to make it a liquid and external pressure is provided by an atmosphere and so you need a planet that can hold on to its atmosphere such that when it's at the right distance from the star the water ice will turn into liquid we have a warning sign that the not all planets can retain their atmospheres and the warning sign is next door when we look at Mars Mars lost its atmosphere and we don't see any form of life crawling on its surface right now there might have been an atmosphere with liquid water on its surface earlier on and that's what the kind of evidence we're seeking but the lack of atmosphere prevents liquid water from existing right now on the surface of Mars and so it may well be that those environments near dwarf stars do not allow planet with an atmosphere on which life can be developed as comfort comfortable as on earth because of the storms and the wind of those those stars and that would explain why the first example ourselves that we find is next west are like the Sun that is not so typical but relatively quiet even though it's short-lived and not a typical stump now you asked asked also about these ice worlds and and those this is a very interesting possibility I mentioned before that you need to be close enough to a star in order to have liquid water but potentially you can have an iced shell if you're not close enough if you are too far away from the star and underneath the ice there could be liquid water and that's the situation for example in Enceladus or in Europa and an interesting question is whether life can develop under the ice in the liquid water my own sense is that probably yes for primitive life microbes or bacteria might develop under these circumstances but it's unclear whether complex forms of life can develop without having an interface between rocks and in liquid liquid water and the reason is that this interface between rocks and liquid water helped for example to enhance the concentration of chemicals and develop very complex molecules because what happens is you make these puddles of water and then the sunlight evaporates the water and increases the concentration of mickleton that process by itself could be extremely important in allowing the chemistry of complex life so so I'm not clear about whether you can develop complex life under an ice shell but but primitive life possibly and my my general perspective is that of cosmic modesty I think that we are not special I mean there is this tendency of humans to think that we are special and you know it started with people thinking that we are the center of the physical universe that the Sun moves around the earth then we realized that's not that's not true we're not at the center of the physical universe in fact the physical universe has no center from any vantage point you see this roughly the same X cosmic expansion to one part in 100,000 and very feels so the universe has the same conditions in many places on average and there is no tent or treat now people still tend to think that the biological universe the living universe might be centered on us that we might be the only form of life or advanced life in it I mean it's flattering to think that way but and it's also understandable because when I look at my daughter's you know when they were young and they thought that everything centers on them but but as they grew up they matured and we got a better perspective about life and so our civilization in my view needs to mature and one way to mature is to for my daughter's was to go out to school or to go to kindergarten and see other kids and realized that you know but there are many out there with similar talents and as the way to maturity civilization would be to find evidence for life away from Earth and moreover if that evidence comes in the form of signals from an egg terrestrial civilization that would be even more educational for us because we could then not only realize that we are not alone but also learn from them there are a billion years more advanced than we are then the technology and science are far more sophisticated and so we can make we can make a leap in our understanding of technology and science by listening to them but seeing what with what what they're doing so they might feel like cheating in an exam where we get answers to questions that we haven't figured out ourselves still it's it would be very rewarding to learn for more advanced civilizations now you have done work in addition to radio signals you've done work in such things as bio signatures and techno signatures that are independent of radio can you tell us about those yes so but them actually involved right now in writing textbook on the search for both primitive and in telogen life away from Earth because I believe that's the most exciting frontier that awaits us in science and it will have dramatic implications for our understanding of our place in the universe and the deep cultural effects on our society if we ever find evidence of this type so what I worked on are ideas that are that indeed go beyond the traditional way of looking for radio signals one of them had to do with searching for artificial light so when we look in the solar system for example objects like asteroids reflect sunlight and they get dimmer as we move far away as the inverse of the distance to the fourth power and simply because the amount of light they intercept goes like 1 over distance squirrel away from the Sun and then the Este as they go further from us they get dimmer because of the inverse square law so altogether it's 1 over distance to the 4 but if an object produces its own artificial light for example if there is a city on some object or if there is a spacecraft roaming through space then there would be a dependence of just 1 over distance squared as to how the object gets dimmer as it moves away or approaches us and so there is a simple way of telling measure the distances of there is a simple way of telling you know whether it's producing its artificial light and surprisingly nobody really tested whether all the objects in the solar system that we see many of which are our way in the Kuiper belt for example whether they follow one glow or the other and that's one suggestion that I made check for artificial lights another one had to do with industrial pollution so people are thinking about searching for oxygen or other biomarkers as signatures of life primitive life because know that if life did not exist on earth then within a million years all the oxygen in the atmosphere would have been depleted it's a very reactive molecule and so oxygen is regarded in combination with methane as a good biomarker a signature of of primitive life but since we are contaminating our atmosphere with pollutants I thought it might be interesting to look for industrial pollution in the atmospheres of other planets and that can be done with the same telescopes of searching for signatures Fox agents and we found that in the future let's say a decade from now if there is a planet with pollution that is about ten to a hundred times larger than then we are civilizations civilization produced on earth then it might be potentially detectable with some significant effort but it could be potentially detectable then another interesting directive that I explored had to do with artifacts on the surface of planets so for example for Proxima be this planet next to Proxima Centauri the nearest star to us that planet is really locked and shows the star the same face at all time so once that one side is a permanent they decide where there is a lot of illumination and it's hot and the other side is the permanent night side which is cold and if a civilization occupies the surface of such a planet it probably would like to transfer some of the light and heat from the permanent decide to the permanent night side and produce electricity in the process and so one way to find out about that is to search for photovoltaic cells be my put on the day side they might cover it with photovoltaic cells or solar cells to collect the light and then transfer some heat or light the other side of the planet and it should be pretty straightforward to detect these effects by monitoring the light curve of the planet so as the planet moves around the star it reflects the light from the star if there is nothing artificial going on there and without even resolving the planet you can monitor how the combined system of the star cluster planet changes its flux so when the planet goes on the other side it's hidden from us but once it exits from the shadow of the star then it reflects it acts as a mirror so we see more light sort of like the phases of the Moon and when it's sideways we see only half of the one hemisphere being illuminated and so the light the combined light changes with time but if there is some artificial redistribution of light or heat we could tell that it exists from the combined light and then and that's a simple way of telling so that's in terms of photovoltaic cells or redistribution of heat or light there are also structures that one could look for around stars mega structures that could reveal the existence of an advanced civilization and by the way the interesting thing about those and also about photovoltaic cells is that they could outlive the civilization if it civilization destroys itself through a nuclear war for example we might still find the artifacts that they created it would look like a graveyard of a civilization and we would see that there is no evidence for life there but we could still detect artifacts that could not be produced naturally how long would such a thing last how long would you see these artifacts and/or around the star and the light curve would it be millions of years or billions of years well eventually what will happen either the surface will be covered due to dust or or rocks due to impact of asteroids or and there would be some plate tectonics that reshuffles the surface and the estimates are the you know it could last for at least the ten to the five years hundred thousand years which could be much greater than the civilization I mean if look at world politics you know we had nuclear weapons for perhaps I mean it's been a century but the risks from nuclear wars is still you know quite imminent and it's conceivable that civilizations will destroy themselves within a matter of centuries and in that case the the relics of those civilizations would outlive them you know a thousand times longer or a hundred times longer so that means that if you go out and search then most of the time you will find these ruins only one in a hundred that would be still living if they all follow the same fate of course there is the issue of you know some of them might be smart enough to collaborate and live peacefully and also not all will follow the same evolution in the same history that that we are following so by the way by searching the sky we could learn more about whether what we do is typical or not whether for example if we find other civilizations we can study them and learn if the rules of ethics are universal we believe that they're universal you know that some ethical rules are you know are really that the right way okay but but we could see if that's true out there we could them you know and that will give us a better perspective about the way we behave in the path whether we can improve ourselves because it's if for example we find that peaceful civilization some much longer live then perhaps that will come down some countries from going to war over you know territorial disputes and in addition we could potentially learn about whether we you know we are typical we're whether we are outliers whether there is free will or whether you know it looked like all of them are doing very similar things to what we do and there is nothing really unusual in the way we behave what what promise as far as finding evidence like that in light curves what I know we had Kepler and Kepler saw odd stuff like K I see a four six two eight five two and things like that but moving forward in the future I want to ask you about what instruments like the large synoptic survey telescope is going to do for us but before we do that I need to go to break and we would be back in a moment [Music] we here at event horizon believe in communication with our content consumers and this is where I'd be plugging our Google+ if we had one but we don't so I won't mention it however we do have Twitter and Instagram you can find it at j mg event horizon or something to that effect and now back to john and i am back with professor Abraham lobe of Harvard University a professor that we were talking about tabby star Kepler and which I suppose that's essentially over now for his omission but how they had discovered odd things odd stars in their light curve nothing that was particularly convincing to be of alien origin but it still found odd stuff what what chances do we have with the instruments that are coming like the Oh SST what chance do we have of detecting something that could be of alien origin in an electric of the star well it's difficult to quantify the chances for finding life because there are many elements of the origins of life that we don't fully understand but one thing that can be done is estimating the relative likelihood of success in the search for life in between the search for primitive life and the search for intelligent life so the reason that we can do that more quantitatively is that we know roughly the volume that we can search through and the volume is much greater for intelligent life basically within our galaxy we can pretty much look throughout the galaxy for radio signals or optical signals from lasers so most of the stars potentially could host interesting sources that involve intelligent signals however in the search for primitive life the most compelling method right now appears to be transits you need the planet in the habitable zone that is that has roughly the mass of the Earth or the size of the earth going in front of its host star such as the light from the star will pass through the atmosphere of the planet and we will be able to infer the composition of the atmosphere so the search is really for molecules that are biomarkers they're markers of life in difference from the search for intelligent life that is looking for signals that are Technol signatures so we're comparing bio signatures to techno signatures and of course one can search for techno signatures as we discussed before by looking for artifacts on planets but that that will be limited to nearby stars so the more effective method would be to search for radio or optical signals and in fact in a paper that we are reading today with my colleague manasvi Lingam we are comparing the relative likelihood for success in the search for intelligent versus primitive life and this is important because federal support for SETI for the search for intelligent life stopped back in 1993 it was renewed recently through private funding in the context of breakthrough lesson which is a project funded by the breakthrough prize foundation by yuri milner to search for artificial signals from space but the federal funding is not there as of yet and it would make sense it would be prudent to advocate calibrating the the level of federal funding based on the own estimates of the likelihood of success and so the the search for primitive life is very much part of the mainstream of astronomy for example the James Webb Space Telescope that is a currently planned for launch in 2021 in about three years that telescope altogether will cost of order 10 billion dollars including some operations cost and a significant task that it will follow is searching for primitive life in the atmospheres of other planets so a fraction of that 10 billion will go to the search for life on exoplanets and you know this this telescope would the project will take up to a decade or so but there is also some other money being dedicated to the search for primitive life and then altogether it's at the level of a fraction of a billion dollars per year so then how much less likely is it to find intelligent life we try to estimate that based on the lifetime of the civilization and the the detectability in terms of them beaming the radiation to a certain angle and so forth and we found that if they have similar technologies to those that we have and they just broadcast similarly to the way we are then you would it would make sense and to fund SETI at the level that is two to three orders of magnitude less than the search for primitive life so we are talking about 10 one to ten million dollars per year for a civilization that has a lifetime of the order of ten thousand years for a lifetime the minimum lifetime that would make sense to consider to contemplate is about a century because we already are going through one century with our civilizations so so it the bottom line is that at the very least it should be a million years per year and the breakthrough listen program does more than that but but we think that as a community that Shan owners should support both searches and on other planets and they should be conducted concurrently although with a significantly higher funding dedicated to the search for primitive life just because it it offers a higher chance for success what do you think the chances are do you think we have any prayer of finding a civilization given that they may not last so long and we've only been visible for a very short time as far as the radio goes but life on Earth as far as our altered atmosphere with the oxygen and the methane levels that we've been visible for a very long time in that case so it is is there a much better chance of finding primitive life or even plant life through the vegetative red edge is there a much better chance of that than civilizations and you know what that's that's not entirely clear because then well first of all the the search volume for intelligent life is far greater you have the entire galaxy versus a few hundred light years around us where we can use the transit method on bright enough stars but beyond that even if there is one advanced civilization that existed in the Milky Way let's say a billion years ago and it's long lived even one such civilization would spread itself once they become advanced enough they will not sit still on that planet they would construct spacecrafts and move away and they could in principle populate other planets with copies of themselves there could be lots of spacecrafts roaming through interstellar space that we can't detect so it may well be a detection threshold issue that you know we have telescopes that are sensitive to a certain level right now they are not sensitive enough so we don't see much evidence for activity but once we reach a threshold we would see you know a huge traffic out there and you know it's similar to what happened with the LIGO experiment that there was aim to detect gravitational waves many years they haven't anything but once they reached thresholds sensitivity started seeing events routinely and the same way may happen here my own sense is that biology I've on the surface of a planet is the least interesting type that we we could find I think it's quite likely that advanced civilizations produced robots with artificial intelligence with machineries that go beyond biology because you know a human body is not designed to go through space for a long period of time the journey is long and there are lots of risks out there but if you build or something artificially you can design it such that it will be optimized to those conditions and you can equip it with a 3d printer and put the information that you want to application the target planet so basically if you want to have humans there you upload to the computer system the DNA of human and you equip it with a printer capable enough to produce a human from the raw materials available on that planet you don't need to send a human you don't risk by doing so you don't risk the life of someone you care about so it's only about transferring information and mooted having more copies of the same elsewhere and it doesn't need to be in the traditional way of transporting the same person from one place to another you can transport the information about the person and reproduce that person there and that seems to me for in a very advanced civilization the right way to go because then you can go to many places the same time have multiple copies and not worry about losing one of them and if we think even bigger than that it doesn't need to be restricted to our own galaxy as I mentioned before the universe is expanding at an accelerated rate that means that it's not just expanding but the speed of distant galaxies away from us is growing with time and so eventually each of these galaxies exceeds the speed of light relative to us and after that point there is no way for us to communicate with the habitats of that galaxies of that galaxy so so the universe the fact that there is this cosmic acceleration implies that we will run out of resources if we stay within our own Milky Way galaxy it has a limited amount of resources and that's the only thing that will be available to us in the distant future because all the other galaxies will recede away from us there is a way to avoid that and I mean so I wrote a paper about this future the the lonely future that the universe brings to us due to its accelerated expansion and I got an email from Freeman Dyson about five years ago where he said well we shouldn't accept that fate that cosmic fate perhaps we should collaborate with other civilizations and assemble as much matter as possible in one region of space such that this matter will be bound gravitationally and will resist the cosmic expansion so once you have bound matter there is the unit the expansion of the universe doesn't affect it and so that sounded to me and he advocated cosmic engineering and that sounded of outlandish and that would be quite the techno signature to move stars or to move galaxies around would require much more [Music] envisioned and then I think how are my capabilities that we cannot envision right now and and so but I I told him you know not not always lost because in fact such objects exist they were assembled by nature the biggest objects in the universe are clusters of galaxies and they contain up to a thousand times the mass of the Milky Way galaxy and there are two nearby ones there is the Virgo cluster the nearest one which is about sixty million or a little more light-years away and there is the the Coma Cluster which is richer so in principle we just need to prepare ourselves into those clusters and then we'll have a thousand times more resources there than we have in the Milky Way so the best thing to do actually for a civilization for an advanced civilization is to migrate right now in the next few billion years to a cluster of galaxies that offers the biggest reservoir of resources such that in the distant future when the universe becomes empty such a civilization will have access to a thousand pounds more more fuel than it had in its original galaxy now there is another reason to move away from your your galaxy and that is to preserve to maximize the longevity of your species your civilization if you populate other galaxies that will eventually run away from from us at the speed greater than the speed of light then anything that happens to us if there is some catastrophe in our volume of the universe it will not affect them because they're completely causally disconnected from us even signals from us cannot reach them sing on signals and so anything catastrophic that happens in our region of space and time cannot reach them and so if you spread your descendants in regions that are completely disconnected from each other and the universe does it for you universe separates all of these galaxies from each other except for those in clusters of galaxies so the universe is can be thought of as as preserving capsules of of copies of us that will not suffer the same fate if something bad happens in our region of space-time and and so that's a second reason to do that to move away from the Milky Way galaxy and it's quite possible that other very advanced civilizations in the universe started this migration and you can think of of this migration for example into clusters of galaxies as being similar to the migration of civilizations on the surface of earth towards water resources so civilizations used to move in to the banks of rivers and places where life would be more comfortable and and the same can be thought of in terms of migration of advanced extraterrestrial civilizations to clusters of galaxies so couldn't that be a plausible solution to the Fermi paradox that as soon as civilization reaches a certain stage they leave their galaxy had often to intergalactic space and head towards a cluster it's quite possible but in order to do that I must say that you need to develop a technology that propels the civilization at a fraction of the speed of light much more than chemical propulsion provides you you need them at least 110 to 100 times faster engines and actually as it turns out our civilization is just starting the puns of contemplating such travel there is another project of the breakthrough price foundation called breakthrough starshot and I happen to be the chair of the advisory board for that project and that project aims to send a probe to the nearest star Proxima Centauri or the Alpha Centauri system we that will reach that system within a couple of decades the reason we think about a couple of decades is that the funder you Romina as well as myself I mean we're the same age 56 and if we contemplate a project that is centuries to accomplish we won't be able to see the fruits of that and it's difficult to get people engaged in a project that takes longer than their life span and so if you use a chemical propulsion to reach Proxima Centauri it will take about a hundred thousand years and you know think about where we were a hundred thousand years ago and so by the time the spacecraft reaches of the Proxima Centauri our civilization if it still exists we will have technologies the far more advanced than it had when the launch started so it doesn't even make sense to send something because it would take it longer than the time it takes for us to develop a faster engine the Voyager 2 effect were you your technology overtakes and you end up retrieving the spacecraft with the Golden Record on it and bringing it back to a museum exactly and so and so we were thinking of propelling a spacecraft at a fifth of the speed of light such that it would reach Proxima Centauri within 20 years that the star is about four light years away so it will take 20 years to reach it at 1/5 of the speed of light and how would you accelerate it to that to that speed that's a very good question because even with the nuclear fuel you don't have enough energy per unit mass to produce a rocket that will reach that speed so so there is a limiting speed that you can reach with with a rocket which is dictated by the energy per unit mass of its fuel and and and it's just impossible to use rockets for that purpose however one can use light because light propagates at the speed of light so it can in principle push on an object that moves at a fraction of the speed of light and in this way you leave the fuel behind you are not carrying it with you the reason that Rockets are not very effective at reaching high speeds is because they carry the fuel with them so you are accelerating not just the payload but also the the fuel until it burns and that means that you know all the chemical rockets that we launched since the time of Apollo until now reached roughly the same speed I mean New Horizons was moving roughly the same speed as Sputnik you know it it's not we we haven't benefited much from increasing the amount of fuel on the rocket and you gain only logarithmically and and so the end result is that you need a completely different technology that leaves the fuel behind and one way to do it is by using a very powerful laser beam a beam of light shining on a sail and pushing it through the reflection of the light so it's just like sail a sailboat being pushed by wind here the push is coming from the reflection of light rather than the reflection of air molecules of the sail and since light moves at the speed of light you can in principle reach a fifth of the speed of light for that you need a laser as powerful as a hundred gigawatts which we don't have at the moment and you also need a very lightweight payload and sail of the order of few grah and if you go through the numbers you find that with a few grams sale and a hundred gigawatt shining on it for about a few minutes it can reach a fifth speed of light over a distance that is about five times the distance to the moon and in principle you can keep the laser focused across that distance you just need to make sure that the sail does not absorb more than one part in 100,000 of the laser light it just reflects it because otherwise it will burn up and then you need to equip the sail with a chip which we currently have in cellphones we can pack a small camera and navigation device communication device in a chip that weighs less than a few grams and so that part is feasible already right now and there are two basically technological breakthroughs that enable this to happen now even though the idea was suggested back in the 60s 1960s by robot forward who was a science fiction writer shortly after the laser was invented he suggested using it for propulsion but now this idea can materialize because of two revolutions one in laser technology the cost of lasers drops according to a law that looks just like Moore's law and then also thanks to the miniaturization of electronics we can pack together a camera navigation device communication device in just a gram of payload and then the hope is you know if we launch it in the right direction let's say it would take a few minutes to to launch it to a fifth of the speed of light and then it would take 20 years to reach Proxima Centauri it could take some photographs of the planet next to it tell us if it's green blue or yellow that will indicate whether there is vegetation some oceans or desert on its surface and then it will take another four years for the image to get back to earth so potentially I hope to live that long to see the image but even if not my I hope that my daughters will be able to it myself we have to take our final break and we'll come back for our final segment so we'll be right back I'm supposed to inform you about subscribership I'm something to do with a cowbell if you are one of the few people who can interpret this cryptic instruction please follow it and we're back doctor you also work a lot in astrophysics and cosmology and I wanted to ask you a few questions about that you have said in the past that the way physics makes progress is by anomalies which sort of works into what we've been talking about something unexpected being discovered elaborate on that yes so often in modern science we have a well-respected theory supported by experimental data and everyone interprets the data that is coming in new data that is coming in based on that theory on that paradigm but every now and then the theory seems to break down that there is a new phenomena discovered that violates the underlying principles of the theory in what often happens and that's not well recognized is that the mainstream of science immediately immediately reacts that and says oh no that's not really an anomaly we can perhaps explain it away one way or another it's it's not really important and if you think about it that happened with the Furious epicycles before it was realized that the planets move around the Sun that even though the evidence was sort of going in a different direction then the interpretation of the evidence was quite different I have another example which is the Mayan culture I visited the Chichen Itza in Mexico and the tour guide when he showed us these beautiful buildings that advanced the civilization of the Maya constructed he mentioned that astronomers held a very high position in the society in the my own society and they were called they had political power there they were called priests astronomers and they benefitted from the highest status in society and the reason for that was that people believe that you can forecast the future based on the motion of planets or other celestial object and so for example Mars the motion of Mars can tell you something about whether a war is likely to end in a win or loss and some alignment of celestial object could could inform you about some other deals that the society is making and so once they had that theory they decided that it's it would be very helpful for their economy to actually employ astronomers that would measure very precisely the motion of celestial objects on this type and so they provided the best chance for these astronomers and they had these observatories where the astronomers would watch the sky and the psalmist documented the motion of objects on the sky sources on the sky very precisely for two thousand years or so and so this was a very advanced data set that they develop but they interpret the data is telling them what the future is like and retrospect if we think about it they didn't come up with capital both of that's moving around the Sun and they didn't come up with newton's laws even though they had almost perfect data and what it shows is that data good data is not enough you need to be willing to change your interpretation and you see this denominator reduced scale in modern science that whenever the reason anomaly people try to brush it off but eventually if it if there is enough evidence then it leads to a revised version of physics and we see that with quantum mechanics and even after quantum mechanics was measured in the laboratory Einstein thought that it's still it must be deterministic the way classical physics was but he was wrong about it it was completely different and we still don't fully understand all of its implications so so that that has to be kept in mind and and anomalies are really key to revising our view of reality now you say that ancient cultures such as the Mayans and actually quite a few did not hit upon Newtonian physics is that because it just wasn't culturally possible for them to do that they just didn't have the right environment for it or is it that certain theories within physics are sort of like Black Swan events where they're they just come out of nowhere else such as you know Newton's Newton's laws but also general relativity do you think that sometimes something that's very far ahead of its time just just someone with the right insight comes up with it it's possible but the point I'm trying to make is that if the culture is a whole it believes in the wrong idea for example that we can forecast the future based on the motion of objects on the sky then it's more difficult to develop these these scientific the correct scientific ideas that's all I think now may well III don't for a minute I don't think that for some reason people in Europe were brighter than people in South America on the contrary I mean the fact that the pion the Mayans developed earlier indicates that they were extremely bright it's it's just a question of what the culture limits you to think about and and we should free ourselves of prejudice when we interpret anomalies that's the point I'm trying to make that if you are trapped within the way of thinking of the past you will never give up and you know there are examples of scientists that only when they died the paradigm changed you know that it wasn't possible to change the paradigm in their mind beforehand because despite the evidence that was collected they would always interpret an insulin convoluted way it's such that it supports their incorrect view and you know that's human nature we prefer not to admit again II prefer not to admit mistakes but the nice the beautiful thing about science is you let the experiment test your ideas and you should be willing to give up on ideas if the data comes differently than you expected and if the the the subtlety is that if the data comes close to what you expected most of the time you should still be open-minded to the possibility every now and then a new phenomenon will open a new window for you your understanding of nature and that's the part that is not fully appreciated people tend to think that if most of the time you get the right answer then if you get the wrong mans that one out of a hundred cases perhaps you can brush it away and explain it some other way that's not necessarily true perhaps the best case might be Einstein in that of course early in his career he was right and then all of a sudden God does not play dice with the universe regarding quantum theory and he just could never accept spooky action at a distance and things that today we you know are accepted mainstream science right yeah but one can understand that I mean he came up with many important ideas prior to that he made some other mistakes around the year 1939 1940 he argued that the black hole's probably don't exist in nature and he also argued that the gravitational waves probably don't exist around the same time and both of them were actually verified but doesn't his theory predict that gravitational waves well so that's the point that the mathematics of the theory is complex and and back in 1940 it was not obvious that gravitational waves existed are not just a mathematical curiosity that is not really physical and he wrote a paper about it with black holes basically argued that star cannot collapse two if it has a little bit of spin that rotation is thought that spin will prevent it from collapse but exactly hundred years after his theory was the equations of history were written by him we discovered the like of Herman discovered gravitational waves from the collision of Kubla cause at the edge of the universe and clearly demonstrated that both of these exist and I think Einstein would have found this discovery to be amazing given what he wrote back in 1940 now back to anomalies in relation to advancing physics are there any anomalies that you're looking at that you're interested in that you think might be a revolution at some point well it could be that the fast radio bursts are something different then most astronomers think they are not related to young mutant stars newly born neutron stars at cosmological distances we don't know we have to get more data and get you know identify the distances and environments on almost all of them except for one that repeats for which we were able to find out where it is of course there are normal ease that are part of the standard paradigm for example dark matter and dark energy so dark matter there was a lot of evidence for method that is not visible to us doesn't interact with light and nevertheless we can tell that it exists based on on its gravitational influence but at the same time it could be that the way we calculate gravity is wrong and that in fact it's not that there is more matter out there but the laws of gravity are modified so you know that always has to be kept as a possibility until we find detect the dark we understand its nature most astronomers most cosmologists believe that it's made of elementary particles that are just brutally interacting and we haven't yet discovered them but people hope to detect them back the search for dark matter in the laboratory has been ongoing for decades now with no success and so one has to wonder maybe you know that perhaps we have the wrong ideas another anomaly has to do with the accelerating universe which could be explained by the energy of the vacuum if the vacuum is not completely empty but has some energy density to it after you remove the matter that would cause a cosmic acceleration and and that's the origin of a cosmological constant einstein's thought about a century ago and we seem to have such a cosmological constant but but it's very pathological it's it's much smaller than would be expected from particle physics some 120 orders of magnitude and we would expect it to be much bigger than it is and an interesting question is why is it so small why is it not zero that's one of the most fundamental questions in physics that is not answered at the moment there is another anomaly in the case of black holes for example where black holes can be characterized by three numbers their mass their spin and their charge and the rest of the information that goes into them is swallowed by the black hole and we have no trace of it and that was the story since they were first invok'd about century ago but since then Stephen Hawking discovered that black holes evaporate and and he calculated that s they evaporate they behave just like a hot object they radiate thermal radiation and that radiation doesn't carry any information other than its temperature and so eventually you can end up in a situation where you make a black hole out of the Encyclopedia Britannica it had a lot of information in it by now it's useless we have Wikipedia we have advocate so people can make a black hole out of it and all this information will be swerved by the black book and then it will eventually evaporate into the thermal radiation and that will carry none of these informations and interesting important question is where does the information go this is called the information paradox and it may signify something deep that we don't fully understand about how to marry quantum mechanics and Einstein's theory of gravity general relativity because Hawking did this calculation understand some under some assumptions involving both both of these theories but we don't have a quantum theory of gravity at the moment that is experimentally tested and verified and so it's quite possible that we have the wrong ideas about how to combine quantum mechanics and gravity and that would resolve the information paradox we know that at the center of a black hole there is a singularity and that is a breakdown of Einstein's theory of gravity and it's probably replaced by some quantum mechanical object and I came to think about this in particular recently because we had a flood a flooded basement the sewer in our basement was clogged by roots from nearby trees and and the basement was flooded and then I in the five hours that it took me to help the plumber to fix the problem I thought that it's actually an interesting question also in relation to black holes because when matter falls into a black hole we don't really think about it goals just the way we don't think about where the water goes where the shore goes when it goes down the drain but in order for the sewer to work the water eventually needs to go somewhere it goes to some facility that has a reservoir of water there and it collects there and the same thing could happen in the case of a black hole there might be a quantum object into which all the matter that falls into the black hole goes and it's not like a facility that collects this matter - a very dense state but definitely not what we currently have in mind for for the singularity because we don't have a quantum theory of gravity so here again there is some something about unification of quantum mechanics and gravity that we don't understand and potentially an anomaly in the form of the information paradox that could be related to it also about the early universe first how the Big Bang happened then what was there before the Big Bang and that kind of a breakdown of Einstein's theory of growth that singularity the Big Bang singularity is also an anomaly and we don't understand it I absolutely love that a flooded basement lead it leads to new thinking on a black hole now that's an anomaly to me it comes naturally I have to tell you that very often I speak with a young person that comes into my office and he tells me about a paper that he wrote us and then I asked him and what about that and he says wow this is really interesting we should explore it together and to me this idea came just you know immediately out of the blue with not much effort and it just unclear to me why it wasn't obvious to this person in the first place and the same was is true about you know I I enjoyed by the way speaking to any person that comes through my home to fix things like the plumber or electrician or whatever there are people that are down-to-earth and and and I have common language with them and and to me science is part of life it's not as if you know this is an occupation nine-to-five I get paid for and then when I go home and I forget about it it's just the way I think I'm very privileged to get paid to do to think about these things but thinking about these things is not a result of the fact that I get paid and for them it's just you know it comes to me naturally and and under any circumstance and I'm fascinated by that now when you think in terms of most of the matter in the universe being dark matter is that unsettling for you that we just don't know the answers yet to what this weakly interacting materialism what what does it have to do why is it only gravity what that interacts does that yeah it is unsettling and most recently there was some evidence about the early universe that you can think of as an anomaly there was a discovery a report a report of the cosmic detection of a signal from cosmic dawn when just before the the first around the time that the first stars formed that indicated that the the hydrogen in the universe was potentially much colder than than possible in the standard cosmological picture that we have and one possible explanation is that we came up with and we wrote the paper about was that you can explain it if the Dark Matter a small fraction of the dark matter just let's say 1% of all the particles of dark matter have a small charge electric charge something like a millionth of the charge of the electron and that would allow them to cool the the hydrogen atoms to the level that was observed and so here is an interesting situation where the reason anomaly that was reported we came up with this idea and it could be tested by more data that will be collected in the future the last thing I want I want to end the show on something you mentioned that absolutely fascinated me you can see the idea of a double black hole ejecting a star possibly with a planetary system depending on on that star and accelerating it to near the speed of light tell us about that yes so a system of two black holes that are bound to each other so they move in orbit around the common center of mass such a system can add act as a slingshot if a star happens to pass through the orbit of the two black holes then the star can get a kick from the motion of the black holes sort of like in a slingshot and if the star passes close enough to the at one of the black holes it can reach near the speed of light when it's ejected so we actually went together with postdoc of mine James Gilligan we did a little calculation of the likelihood of that happens because we know that galaxies tend to have a massive black hole at their center every almost every galaxy has a massive black hole at its center and we also know that taxis come together they emerge so for example we are expecting to the Milky Way is expected to merge with Andromeda galaxy which is its sister galaxy next door within a few billion years we can see a draw at approaching us right now and it has a black hole at its center just like the Milky Way and within a few billion years the night sky will change one can actually calculate what would happen as the two galaxies merge together you will end up instead of two disks you will they will mix up the starch mix up and make a football shape a galaxy an elliptical galaxy and then the two black holes will come closer to each other through scattering of stars and eventually they will become bound to each other so that's one way of making a tight binary a pair of black holes orbiting around each other and that binary gets tighter and tighter as time goes on as it scatters stars and and has some friction on the gas in in the core of the galaxy and so the end result that you can get two black holes that are coalescing without merging but still over a very long time scale they can eject stars at high speeds during that process and that process is quite common because the mergers of galaxies take place throughout the universe all the time and so what you end up with is lot of slingshots that are ejecting stars filling up the universe and so there is a sea of stars that are moving up to a fraction of the speed of light through the universe and we calculated the abundance of those stars and none of these was observed as of yet but our paper was the first to point out that they should exist and it's interesting to think about the fact that if you happen to live on a planet a habitable planet around such a star and you get ejected with the star while still being boundary you would go through an amazing journey I mean obviously life will not be easy this slingshot face because there must be a very hot and bright environment near near this black hole so software that life could survive but but just imagine being on a planet and surviving the journey and then seeing basically being flung out of the center of a galaxy at a fraction of the speed of light and going through the space in between galaxies and making a journey through the universe in principle if there is if life can survive could be one way of introducing panspermia between galaxies but more likely these stars are just going through space and and we can they can you can see galaxies as you pass near them if you happen to be on a planet around such a star what would time dilation be like if they were traveling near the speed of light their solar system what would they see is they cross the universe of course the image of objects or sources and London would look deep and if they look in the direction of motion or against the direction of motion the the theory of special relativity tells us specifically how the images would look like but most of them would not move very close to the speed of light there are fewer and fewer as you approach the speed of light it will be a fraction of the speed of light so these relativistic effects will not be dramatic but but nevertheless it's one way of reaching the speed of star shot a spacecraft through a naturally available accelerator and launch system that has nothing to do with lasers but does it through the force of gravity in the far future when Andromeda and the Milky Way merge and we have these two black holes what are the chances that our solar system might get ejected so and we actually calculated that a paper with a postdoc of mine TJ Cox and we found that the solar system will most likely move away from the center of the major product that the galaxy that is the combination of the Milky Way and Andromeda which I call the milk comida in the paper I checked that this name was not used before that it's not it hasn't have any bad connotation and we called it milk comida so the the Sun will be located most likely farther away from the center of milk comida then it is from the center of the Milky Way right now it will also probably not move in a circular orbit it will be an eccentric orbit and there is a chance that it will be grabbed stolen gravitationally from the Milky Way in the first passage of the Andromeda galaxy so we might be able to see the Milky Way from a distance because the Android galaxy will bind us to it but eventually when the two galaxies merge will probably be relocated to a greater distance from the major product however we will not be anywhere close to the black holes because they are at the Centers of of the two galaxies so we are far enough from the center not to to to reach there so someday earth will become part of a completely new galaxy formed from - one of which if you you know you can see Andromeda with the naked eye on a very dark night I find that amazing yes but toy science there are lots of amazing things that we discovered by now but even more that we haven't discovered my personal perspective is that our knowledge is like an island in a sea of ignorance and and personally I hope to just increase a little bit the area of this island during my life but there is plenty of work left for future generations and that includes the search for life in the universe and possibly traveling to through interstellar space to other destinations and with that we are out of time doctor keep on thinking and keep on writing papers and thank you so much for appearing with us today my pleasure and I will I hope you'll appear with us again at some point I would be thank you clearly inspiration can come from anywhere including simple tasks such as taking a shower talking to a plumber or even watering a garden which is often where I do my own thinking about my youtube channels it sometimes pays in droves just to let the mind wander while doing simple tasks as Archimedes did and dr. Logue does and from this can come great ideas I've read many of dr. Lopes papers over the years he's probably the most cited scientist in the links below on my original channel and this kind of inspiration is sorely needed within SETI for example there are two ways to look at searching for alien civilizations you can look back at old ideas such as radio beacons first laid out decades ago and search for that or you can look forward and wonder if there are other ways to detect ETI as it turns out there are and more are thought of each year from techno signatures to bio signatures new ways to detect alien civilizations greatly increase our chances of actually seeing fruition specifically because it may not be so easy to see such civilizations instead the universe may be a subtle place where civilizations live within their means as opposed to conquering entire galaxies and encasing their stars and Dyson spheres ultimately though one wonders what other Eureka moments are yet to come I doubt Archimedes so long ago could have envisioned our world he simply noticed a displacement of water but that would not have led him to envision a world of internal combustion engines rockets and solar system exploration likewise we may not be able to envision a world thousands of years from now what would that look like we can only speculate and it works the same phrase in civilizations what would they look like what is an advanced alien civilization thousands of years ahead of us like again we can only speculate and we won't know for sure until we actually detect one imagine if it looks nothing like expectations what if it is incomprehensible one thing is for certain whatever may come could be the biggest Eureka moment of all time maybe even a gloops into our own future maybe by seeing them we may gain an insight on what is really possible in this universe thanks for listening this is event horizon with me Jan G and I hope you enjoyed our inaugural episode this show will now be weekly released every Thursday evening where I'll interview all sorts of people both within the field of science fiction and astrobiology but also many other topics I hope to see you again soon and you I thought we had an agreement you're supposed to just announce stuff I am announcing something you forgot to mention next week's guest joining John next week is the author of the Martian and Artemis Andy weir one of my favorite science fiction authors I thought I was your favorite science fiction author you were John and then I read more than just your book you're currently number 640 G thanks Anna I'd hate to hear what do you think of me as a youtuber now you mention it do you have a silver play button yet you know what I'm done I'm just done with you until next week anyway yes Andy we're where we discussed the realities of space colonization writing and what happens when sci-fi authors go obsolete like you John anyway when sci-fi authors go obsolete when a I can write better novels than we can hope you can tune in

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Views: 1,547,142

Rating: 4.6209526 out of 5

Keywords: Albert Einstein, Einstein, Space, Black Hole, Big Bang, Theoretical Physics, Alien Civilizations, Gravitational Waves, Interstellar, Interstellar Travel, Alien, SETI, The Joe Rogan Experience, John Michael Godier, Godier, Isaac Arthur, Avi Loeb, Elon Musk, Science, Extraterrestrial, Fermi Paradox

Id: 6ckgBxRASTo

Length: 87min 1sec (5221 seconds)

Published: Thu Sep 20 2018