Intertemporal Communication

life is a comparative rarity you can survey dozens of world and find that and only one of them does life arise and evolve and persist but we continue to search for inhabitants we can't help it life looks for life why do we search the dark for others why do we hold out hope when every survey comes back empty every suggested hint turns out false why do we keep trying we seem compelled to search for alien civilizations to dream at first contact cultural interchange and building friendships across the Stars it's arguably a product of our evolution we are after all highly social animals living in families groups tribes cities we pre-programmed to be social to such an extent that one of the most harsh punishments we can inflict upon an individual is solitary confinement to deprive them of interaction with other sentient beings and so perhaps as a society we truly are just a solitary prisoner slowly driving ourselves crazy with the sound her own voice desperate to find another to relieve the emptiness even if just for a moment but perhaps that perceived loneliness is merely a product of our often limited way of looking at the universe maybe if we pull back that veil a connection does await us just one of a different kind [Music] we have to accept that our intrinsic and pre-programmed desire to find other civilizations clouds our objectivity aliens have often served as a god of the gaps explanation filling in as a placeholder hypothesis for any and all observations which remain incomplete or ambiguous so powerful is this human bias towards finding alien life that even the greatest scientists in history have slipped and fall Eden otherwise prestigious careers for example in 1778 William Herschel discoverer of the planet Uranus claimed he had observed towns and villages on the surface of the Moon akin to the English countryside the New York Sun published a series of articles in 1835 based off Herschel's work arguing for a population of bat-like people on the moon alongside bison goats and unicorns as our observing capabilities improved eventually disproving the claimed lunes civilizations the thesis was simply transplanted to the next object which observations remained ambiguous that was Mars indeed by the 1830s many astronomers believed that Mars was inhabited in 1877 it's Holly an astronomer Schiaparelli produced a Martian map with straight canal like lines across the surface which was later argued to be evidence for intelligent life by astronomer Percival Lowell an idea that persisted until 1907 as the dates were improved the act of perceiving alien life and the gray and hazy areas of incomplete datasets persists even today every time we look up at the sky and see a light or a blurry dot that we don't recognize that we can't immediately explain there is a tendency for us to invoke intelligent life and alien via KHOU as the only possible explanation and even today scientists do sometimes fall foul of this tendency to see life when then exists for example in 2010 during the press announcement of a new exoplanet pleaser 581d astronomer professors steve-o told the media that the chances for life on this planet of 100% an absolute certainty despite the fact there was absolutely no evidence for life whatsoever and look we're all susceptible and guilty of this because at the end of the day we're all human we can't help but dream over the life in the universe and so you could be sure that you will be reading headlines just like this again in the future the story of our search for life in the universe has been one of constant retreat first we were sure that the moon had a civilization and then we pushed back to Mars and further further until we reached the Stars and since Frank Drake first listened for radio communications in 1960 we've yet to receive any clear unambiguous radio signals from the cosmos searches for optical signals such as lasers or artificial mega structures such as Dyson spheres have all fallen flat of course our surveys are by no means complete for example our radio searches are estimated to have sampled the equivalent have about a bathtubs worth of water within an ocean but nevertheless everything about the universe appears natural we see no hint of anything anywhere that cannot be explained by physics a forest of stars but without any clear signs of anyone living amongst them and so this retreat from the moon to Mars to the Stars has led some of us to question the optimism of early generations maybe just maybe intelligent life is far rarer than we imagined some of you hopefully saw our recent video discussing new work from the colloids lab where we consider these questions the paper re-evaluated the statistical probability of civilizations emerging based on the chronology of Earth's history and it found that although life could be common intelligence may be rare and unlikely outcome rather than an inevitable fate critically that paper concludes that intelligent life could be rare but it doesn't estimate how rare it could be 1% or it could be one in a trillion so let's turn this question around and ask what would it take for us to find ourselves as alone in the galaxy right now now other galaxies could surely be inhabited too but we will focus on our own galaxy because that's really the only plausible chance of having a two-way communication given the vast distances to other galaxies there is a way in which we can calculate what it would take for us to be alone the famous Drake Equation is a formula that calculates the number of communicative civilizations in the galaxy as a function of numerous important parameters as listed here the Drake Equation shouldn't be taken too literally it's really a way of organizing the important factors but it does at least provide an approximate quantitative tool for making estimates when Frank Drake first read it down only the first term had been measured but these days we have a handle on the first three terms thanks to astronomical surveys although it has to be said that the number of earths has a sizable uncertainty to it as discussed on this channel before let's assume that life is ubiquitous for the sake of optimism but also it's a position that's compatible with their own recent work on this topic in such a case the product of the first four terms is around point to one fifth if we combine the fraction of intelligent life and communicative civilizations into just one term fic then we can say that we would be alone the galaxy if fic x L is less than five where L is the lifetime of communicative civilizations so for example if L was a hundred years which is about the time that we've been broadcasting for then fic would need to be less than 5% to result in us being completely alone in the entire galaxy I think that's quite stunning in fact because it's hardly a contrived scenario if intelligent life develops less than 5% of the time and doesn't last for millennia or more then we really shouldn't expect there to be anyone else in the entire galaxy who is actively trying to communicate with us right now and 5% I mean it's kind of a large number in fact I'd actually be surprised based on our raises his core analysis if fi is indeed that high what's more this is almost certainly being overly generous because it ignores the fact that signals cannot travel faster than light and thus a civilisation is plausibly extinct by the time they receive a message so unless civilizations last for a very long time it's very possible that we are the only intelligent civilization in the galaxy right now and if so that would of course provide a simple and natural explanation as to why we don't see any evidence for alien civilizations out there I don't exist that idea is jarring it's unpalatable it challenges our desires and dreams of one day joining a galactic Club it means that this is it the world that you see around you represents this sum total of extant sentient existence in the entire galaxy as uncomfortable as this idea may be I want to explore its consequences with you what does it mean to live in a lonely cosmos and now we've ever doomed solitary confinement [Music] if civilizations are so rare that we are alone then it changes the very way that we look up at the night sky there's plausibly a vast number of living worlds out there but all without thought without technology without self-awareness it puts an enormous responsibility upon ourselves we are the torch bearers of intelligence we are the cradle of sentience we are the wave the universe to know itself what a responsibility we carry them to look after this spark but one might also argue that as a tragedy for what was the ultimate point of everything that we did all of the stories that we wrote the music we sang the sonnets we spoke the philosophies we developed the technology is reinvented the art we created and the moments we shared after we're done it all disappears the universe forgets and thanks to entropy we wash away into dust and dirt it's as if we never even existed you know it's sometimes said as individual you died three deaths the first when your body dies the second when your name is last spoken and the third when any mention of you disappears from the records but if humanity is truly alone in the galaxy then we would die all three of these deaths at once not only would we be cursed to solitary confinement but even that existence would be forgotten expunged from the record of time what a cruel hand that would be for fate to deal us but does it have to be this way think back to Drake's equation Drake wrote down the number of communicative civilizations in the galaxy right now not the ones that have ever lived not the ones that will ever live just the ones who are communicating right now that we've come to accept that even if others do live amongst the stars they are likely separated by huge distances but maybe they are also separated in time in 1955 Albert Einstein wrote a letter to the family of McHale beso a close friend and colleague physicist who had recently died Einstein thought about the universe in a very different way to most of us he saw space and time as interconnected parts of a four-dimensional volume and so in his letter to the family he wrote now he has departed from this strange world a little ahead of me that means nothing for us believing physicists the distinction between past present and future has only the meaning of an illusion a persistent one Einstein believed that the past the present and the future were just part of a broader block universe nothing really dies nothing really ends it just moves through time like any other dimension and so if we insist on thinking in three dimensional terms then perhaps we might conclude that we are alone in the galaxy right now but if we think more like Einstein more like a four-dimensional being then not only desire existence never truly end but the chances that we are truly alone in the galaxy is far less likely after all that would require that in the entire galactic timeline the past and the future no one else ever emerges in our Milky Way galaxy so someone else might be out there it's just that the line that connects us threads through space and time [Music] thinking this way changes our approaches to the search for the civilizations as well as our own efforts in deliberate communication let's take the former first our search program the unidirectional nature of time means that no message from a future civilization can reach us but a past civilization that indeed might be possible for example radio signals can indeed traverse the universe largely unimpeded for billions of light-years representing a message from billions of years in the past sure we can't have a two-way conversation with them but one-way communication is possible they might come to the realization that they are alone and decide to preserve some record of their achievements of their brief existence like a message in a bottle they might build a time capsule for future civilizations to discover potentially a database from another intelligence containing details of their lives society and knowledge we can take this idea of a time capsule a step further because civilizations which engineer these time capsules might themselves have previously discovered time capsules from other civilizations and so their own time capsule would encompass not just their own knowledge and learning but even the knowledge of civilizations past like a daisy-chain through time each civilization passes along the record of the others preserves the candle of intelligence through a delicate network across space-time and so that would mean that there truly was a Galactic club a galactic encyclopedia is just that these civilizations don't coexist with each other each civilization is a keystone a repeating station in the link helping the network to survive not a three-dimensional Galactic club but a four-dimensional [Music] how might these messages be sent through time a good way to tack with this is to ask how we might attempt to send a message through time and of course that would mean sending a message to future civilizations our first thought might be to use radio but a single radio burst would probably not do the job after all once that wave propagates past the distant alien civilization it never repeats and is forever lost we could plausibly build an automated radio beacon locating it in space away from the damaging effects of weathering here on earth it would be difficult to engineer a beacon with a sufficiently large transmitter to communicate much information though the message might have to be something simple just a note that we existed but on the other hand it would have impressive range messages detectable from many light-years away whether or not perhaps at the scale of the Galaxy itself however any electromagnetic transmitted that we built such as a radio beacon will of course comprise of electronic components that will themselves age like anything else entropy will damage and deteriorate things over time and all it would take would be a couple of circuits damaged here and there for the radio beacon to become inoperable another approach is to build a physical artifact designed to be discovered certainly on the earth we've relied on such artifacts to achieve a kind of one-way communication with past civilizations such as the ancient Egyptians and Mesopotamians be it the pyramids the rosetta stone or Stonehenge past civilizations speak to us although in many cases it's questionable that this was their specific intention nevertheless their existence lives on through our records and museums could we hope to achieve something similar for our entire species to some distant future alien civilization the first option would be to build something and leave it in the solar system that would allow us to build quite large and massive structures containing potentially a lot of information however we might not want to leave it on the surface of the earth for Earth's active geology chews up the surface over millions of years not to mention the weathering of the atmosphere similarly if we put it in orbit it would be at risk of orbital decay and long-term destabilization the moon actually offers perhaps the best option being a nearby world with no atmosphere no wind and water erosion and no active geology indeed it's often remarked that the Apollo astronaut footprints will likely outlast our civilization however footprints are just imprints in dust and certainly not an optimal strategy for preserving something through millions of years of time in fact they'll likely be gone in one to two million years the equipment left on the moon by the Apollo missions is far more promising each lunar descent module is about two and a half tons for example eventually though micro meteorite impacts will break down this equipment into dust it's estimated that about point zero four inches of lunar Rock is eroded away every million years as a result of this process so by that calculation we'd be looking at something like a few hundred million years for all of this equipment to be broken down but of course the intention of the descent module was clearly not primarily as a time capsule being made of light aluminium alloy the material is certainly not optimized to be a tough long-lasting component the modules do contain a so called lunar plaque that future civilizations could discover with astronaut signatures and brief messages inscribed but certainly not a vast database of information denser materials like tungsten and osmium or even carbon derivatives like graphene and diamond have far better resistance to erosion and could plausibly last much longer than the aluminium Apollo equipment a 10 meter thick slab of lunar rock should last about 10 billion years given the rate of erosion I mentioned before so if we take a denser material material design to withstand impact something like conformer clad tungsten carbide for example that could be far thinner maybe just a meter thick and still last for 10 billion years however that would make the object very massive it would be something like a hundred tons or more that's kind of comparable to the International Space Station obviously an artifact on the surface would be the easiest for a civilization to spot but an easier engineering challenge would be for us to simply bury a much lighter time capsule under the lunar regolith again about 10 meters or so should do it or stir buried lunar time capsule itself wouldn't be visually obvious from orbit you could still flag that it was there by scoop ting the surface into strange configurations or even just using a simple metal detector clearly we have the technology to land on the moon and drilling 210 meters or even using lunar caves would be challenging but feasible the moon may very well offer the best chance for us to preserve our existence to send a message through time and by the same token searching for artifacts on and near the lunar surface might well offer a chance for us to discover an alien artifact left here for the very same reason aside from radio beacons and lunar artifacts there's a few other possibilities for us to consider one is the Voyager Golden Record since goal wood is a stable isotope it won't decay making it incredibly stable furthermore it's also very unlikely the Voyager will collide with anything just about the only sources of deterioration to the spacecraft will be interstellar dust whose densities are unfortunately not that well known and sublimation sublimation is basically boiling and that might sound very strange that something in deep space could be boiling but anything with a temperature above zero Kelvin will be sublimating albeit at a very very slow rate I haven't been able to find a calculation of this in the literature but my guess is that we'll be looking at least a billion years the problem with Voyager though is that it is just one tiny craft the earth and the moon are easy to spot for another civilization but Voyager is almost imperceptible it would need to fly near their telescopes to have any chance of being detected as in within their solar system the best way to optimize the Voyager approach them would be to build fleets of the things but do it far smaller miniaturize gold and storage devices if we had the ability to cheaply launch small nano probes into interstellar space than we could farm out these things sending out little tokens of our experience and knowledge so that other civilizations in the future might discover them within just a few hundred million years a small fraction of the galaxy's age the motion of the stars would stir these probes evenly across the galaxy like stirring jam into power and so these nano time capsules could be everywhere perhaps even some in our solar system right now the final approach is perhaps the most speculative but it deserves mention astronomer Luke Arnold suggested in 2005 that other civilizations might construct thin sheets in orbit of their star that periodically block out starlight just as planets do when they transit since the object is just a sheet of material with no active electronic components or power systems on board then it should last for a very long time only being perforated by micro meteorites over the eons the shape of these sheets could itself contain information for example a prime number sequence of columns but going further complex two-dimensional patterns could perhaps encode far more information 1 detectable from hundreds of light-years away with telescopes like Hubble or Kepler Arnold's idea is somewhat of a hybrid of a traditional beacon and an artifact it is a passive technology with no electronics onboard and yet it is able to transmit messages across the cosmos simply by blocking out starlight I think the idea that we might start building something like this soon unfortunately seems quite a way off we would need to engineer sheets with size is comparable to entire planets nonetheless this is something we can and really should be looking for around other stars so that's really what I wanted to say today that although there is a good case to be made that we could be alone in the galaxy right now when we expand our horizons to include both space and time there's a much greater sense of optimism that we might one day make contact and yes that contact will be one way not a two-way dialogue but ultimately does that matter if someone stranded and isolated on an island receives a letter in a bottle would it not be a treasured discovery to know that then but they might even be part of a great chain of islands each one floating messages across the ocean about their acquired knowledge and brief existence ultimately when we surrender our three-dimensional notions of contact we're much less likely to be alone untold riches of learning might persist in terms of knowledge scattered across the galaxy just waiting for us to discover them and eventually pass along the baton ourselves there are 400 billion stars in the Milky Way galaxy of this immense multitude maybe the origin of life or intelligence is exceedingly improbable or maybe maybe there are world's something like our own on which other beings gaze up and wonder as we do about who else lives in the dark [Music]

Channel: Cool Worlds

Views: 654,327

Keywords: SETI, search for extraterrestrial intelligence, life in the universe, communication with aliens, time capsule, communicating across the galaxy, interstellar communication, intertemporal communication, communicating through time, one way communication, astronomy, astrophysics, astrobiology, david kipping, cool worlds

Id: aB6kQwZZm5k

Length: 28min 49sec (1729 seconds)

Published: Thu Jul 16 2020