The First Image of Tabby's Star Structure Featuring Dr. David Kipping

what will it look like when we find other life in the universe in recent years there has been a wave of new thinking about just how we might discover biological life on other worlds or even a technological civilization within our own solar system we have several moons that have subsurface oceans such as in solidus and Europa but a host of others that may also harbor liquid water under shells of ice this gives us many chances of potentially finding life that has arisen in our solar system entirely independent of Earth this life would likely be simple but it would answer the question of just how common simple life could be in the universe at large but what's most striking is just how common Iceman's with zones of liquid water appear to be in the solar system and if we're at normal example of a star system then the galaxy itself could be teeming with moons capable of supporting life perhaps even dramatically outnumbering proper planets that could do it in the coming years searching for exomoons and hypothesizing about what they might be like will increasingly take its place in the discussion of studying transiting exoplanets themselves but what if more complex or even intelligent life what would that look like the fact is we don't know and as humans study astronomy in ever greater detail star so anomalous that quiet murmurs through the potential activities of EXO civilizations our eyes one such case is the star kic a 4 6 - 8 5 - which at one point was a candidate for the presence of alien megastructures this is now off the table whatever is causing the dimming of that star seems more likely to be a phenomenon of dust but it's very strange dust and the nature of it whether the activities of an EXO civilization or natural phenomenon may not be completely understood until another example of it is found my guest studies such things including developing two dimensional models of phenomena like kic 8 4 6 - 8 5 2 along with transiting planets and exomoons you have fallen into event horizon with John Michael Gaudi [Music] dr. kipping is the assistant professor of astronomy at Columbia University where he researches extrasolar planets and moons dr. kipping also leads the cool worlds lab at Columbia which includes a youtube channel and a website where you can learn about their research dr. Kings other areas of research interests also include study in characterization of transiting exoplanets exoplanet atmospheres Bayesian inference population statistics and understanding stellar hosts he is also the principal investigator of the hunt for the exomoons with Kepler HEK project Professor kipping welcome to the program it's a pleasure now on your channel on YouTube cool worlds you recently came out with an interesting new way of determining the shape of transiting objects in particular KSC a four six two eight five two or tabi star and this piqued my interest because it the image that came out of that is kind of interesting it's almost like concentric rings am i interpreting that right yeah that was that was something we've been aiming for for a long time I mean when as soon as we saw this light curves from tabi start that was pretty much the first thing I wanted to do was to take that time series photometry and see if it was possible to actually figure out what the silhouette of this thing was it was kind of frustrating because we had no idea of course what this thing was and yet it was so intriguing and there was many many ideas being kicked around including to allude to your question you know idea of you know maybe something like a ringed structure that had actually been argued before for another kind of similar one-off transit Jay 14:07 be I think maybe I'm getting the numbers slightly mixed-up in my head but it was this transit detected by a wasp and has this extremely deep highly structured transit that has been interpreted as evidence for maybe not exactly Saturnian rings but some kind of Sur compliant airy disc and certainly people have thought about that as being a potential explanation it we star and indeed if you fill it with that kind of model you can do reasonably well but equally as Tabitha Biogen showed if you fit it with a model with comets that also works pretty well so it was kind of frustrating that we didn't we didn't want to just posit a highly complex explanation and see if it was a good or a bad match we wanted to actually just see what this thing looks like now when we got this image you're right it does seem to have this central blob of stuff which is apparently circular in projection and then we get a app more or less on both sides in a fairly symmetric way but not precisely symmetric and then some some structure again which kind of looks like it could almost be like a giant tilted ring the y-axis scale that's like at a vertical scale on the on the plots that we showed in that video that corresponds to one stellar diameter so it's really from the very southernmost point on the hemisphere of the star up to the northernmost point the width is an aspect ratio of one so the width therefore is very wide whatever this thing is it is gigantic it is a very large structure either something which has essentially a central book which is the radius of the star with them.this this apparently structured disc around it which is several solar radii or stellar radio in in diameter so one that is it's difficult to tell because it's never resolved the full thing I mean as you can tell it looks like that structure want us to continue north of the image and south of the image but obviously we don't have any way of telling what that what that object would be below those points so we can't fully resolve what this thing is but it certainly looks tempting to say that this is adding to the weight of evidence that this could indeed be some kind of structured system such as rings but I want to highlight that even at the central mass is not a planet so this is this thing has to be semi opaque semi transparent so this is not a planet with rings whatever is in the center that is somewhat translucent as far as we can tell indeed that's actually what Tabitha Biogen and her team scene independently using chromatic observations as I think maybe you talked about before yeah so essentially it absorbs differently in red and blue light therefore that essentially screams dust of some sort very very tiny particulate dust now in a dust cloud just going from that angle in a dust cloud what could cause structures like this I mean if it's a ringed planet wouldn't wouldn't it be safe to assume that it's like Saturn where you have just chunks of ice you know large pieces of ice being shepherded by little tiny moons and held together am i off-base with that I mean could you actually have rings made a very tiny particulate matter like this I don't see why not it's we're all kind of speculate about what they all think of E because there really is no precedent in the solar system for us to have a clear idea as to what's allowed or not allowed yeah there's certainly the structure is suggests that there was there is some gravity shepherding things around here so maybe even though that central book is not clearly one giant fully opaque planet or something there may be embedded within that something small but massive enough to hold on to this cloud I mean that would seem to be a natural explanation as to why it's concentrated in that region and then the the shells or the rings of material around that that's that could be a you know stuff that's fallen off the the central object it's like a bow shock or some kind of shock wave almost that's kind of causing it to have that structure but it's or it could be shepherded by some kind of masses which also at those locations as well its input it's really impossible to tell from the images at least that we've constructed they don't reveal any dynamical information like that so we're hoping our image is another useful extra piece of information that theorists and modelers can use when they're trying to interpret what this thing is but we deliberately avoided that people we try to very carefully avoid making timid interpretation about what this thing is it's very intriguing what would I you know when I first heard it I thought okay if we see a giant triangle something like that then that would clearly be a red flag this is artifice now I think what we see is not obviously artificial in nature and obviously when especially by a Giunta style was first detected that was what a lot of the excitement was about with the possibility that this could be something we all kind of gave that a low a priori probability but nevertheless it was tantalizing enough to warrant us going to this effort of seeing if we catch early construct an image so it doesn't look like something that's clearly artificial at least to my interpretation of these images but hopefully it does give us some some more information about what types when you're testing your models this would give you some kind of framework to to start from in terms of what this what the physical explanation might be now one of the stranger aspects of of the star is that if you have this kind of material there doesn't seem to be any infrared it doesn't seem to be emitting do you think that's stranger is it just people it's just perhaps below the threshold of what we could detect what about the missing infrared in in regards to this yeah that's um that's interesting it suggests that the material is cold that just might can't be too warm and that implies that the orbital period of whatever this thing is cannot be super close the semi-major axis to the start otherwise it would it would warm up and produce some kind of infrared excess especially if it was fairly extended in nature indeed that's how we deter any discs around other stars is by looking for that kind of infrared excess so it's either something that's fairly small which suggests it would probably be in a more less a 2d plane aligned to a structure so it's something that's transiting like a disk almost but it's almost lined up to us so we see very little in projection and this can't see much infrared excess even though it could be warm or it's just a very cold object in the first place and it could therefore be quite extended as well so it's a it's a useful constraint but it's still by itself somewhat degenerate there's still lots of either still lots of ways you can explain that not just a single exclamation so in regards to planets say say this we are seeing some kind of a ring a ring system wouldn't the planet itself the center this be even if it's not within our field if you wouldn't that still cost the start a wobble I mean couldn't the presence of large planets be detected that way so you mean by the radio velocity method for example yes yes yeah yeah I think the that would be interesting or not the velocity constraints exist on this star it is a very tricky starks it's it's quite has enough activity to make it a fairly challenging target and of course it's a catalyst arm which means it's faint so it's it's quite difficult to acquire precise radio velocities on a star that typically Kepler's observes I can't remember the magnitude of this stuff atop my own head but they're generally fainter than twelve magnitude which is kind of challenging for ground-based very velocity measurements so I think it would be interesting if you could get down to meter per meter per second precision then I think he could probably say something interesting you could probably rule out maybe Neptune math stupid math objects I doubt you have ever the precision to get down to really small earth mass things which I think could still plausibly explain this you could still have a fairly low mass object at rush from a subject which represents almost a core surrounded by some very light envelope which is responsible for most of the semi opaque dimming that we see so a loss the constraint would be useful but it would again I think almost like with any other type of observation there's no single observation here which is going to be the Silver Bullet and reveal what's really going on I think what I'd most like to see in terms of fog there's just more of these dips because we don't have a strict period we don't know if this thing is repeating exactly like a planet does once every and precisely every orbital period there are some quasi periodicity s within the light curve but it would be great to see more of these events more which of course what we're trying to accomplish especially Tabitha Biogen right now and if we can get more of these events we can image their structures in the same way we kind of did in a new paper and hopefully even get the multiband observations that tabi got last time once we have a large population of these objects I think will be much easy to interpret them kind of really dealing with a very sparse dataset at the moment in terms of trying to interpret this object so without it without a strict period especially it's kind of difficult to make much headway now there was some weak evidence as I recall for periodicity but it was wasn't very strong at least not yet but at the same time the star is under observation it's been pretty quiet lately it looked like but and I guess it's about to go behind the Sun so there won't be much observation at all yeah but once it comes back the main one that you modeled was the so-called day 792 dip from the Kepler light curve mm-hmm right the one that looked at least initially looked like a isosceles triangle which evokes things like Loog Arnold's paper were you know you could have some sort of unnatural shape passing in front of the star but since this is semi opaque that's probably well off the table right yeah and I mean what was interesting is yeah we can't if you try to just have some kind of opaque structure you can't sit the light curve with that at least that was our finding that if you just let the pics always in that image be either fully opaque or completely transparent there's it's very difficult to find any good matches between that light curve shape and what we actually see so we don't think it's it's likely even ignoring the information that tabatha Bastion has collected since then of the multiple observations even just from the Capitol like if we think we can argue that this thing cannot be a single opaque structure that there really is this just the element to it now was you're right it was the 7-9 to dip week or dip 5 of Biogen star but we also did debate as well because we just took the two deepest ones in analysis and the reason why we did that is because a technique doesn't yet have the ability to account for measurement uncertainty so we wanted to pick the two highest single stories cases where the things noise was so high you really didn't have to worry too much about the effect of stochastic noise on the interpretation and when we apply those the the technique to those two dips even though they're quite different you can one of them has this very smooth but highly asymmetric structure that's a 792 DEP but the second one has all sorts of interesting because and bumps in it and yet still even though there are differences between the two images they do both favor this first order a fairly similar structure something with a central circular projected thing in the middle and then a gap and then two kind of rings if you like or ring-like structures either side it's certainly tantalizing to think that these two things might be the same it might be the same object that's come round for a second pass and yet has temporarily evolved in some way between those two but the problem with that is that if you look into the future doesn't appear to repeat on that strict ephemeris so that kind of blows wind to that little bit so it's that's why it's such a challenge to interpret what this thing could be but whatever the whatever these big dips are they seem to have some kind of self-assumed that structure to each other so they yeah they do they look similar and you also have the odd I believe Day 1540 tip where it looks symmetrical sort of an asset in a similar way where you have this bump and then a big bump and then another small bump is it he dresses out so that does that add more to it as that add more more weight to this idea that there's structure here yeah I mean I think you're in terms of like live morphology I guess you're talking about that like have morphology itself looks a self-similar yes and if you have self-similar like live mythology's you would assume that that means that whatever is transiting is self-similar as well so yeah I guess so but it's an even though there's self similarity there's also enough differences between these that it's a bit you know it makes it very difficult to have a straightforward explanation is there how it could change so much or why all the objects would have a similar structure but not precisely the same structure I'm still genuinely very puzzled about this as I think you can tell we're really hoping to get some it be great if when Tess looks back at this which it will do next year if it was if it gets lucky and it sees one of these big dips again then we'll have the opportunity to have new space base photometry covering a month that would really give us an excellent insight as to this object if we see it happen again so it's kind of a long shot this thing doesn't free transit that frequently but if it does happen to coincide with the test window I think it would be absolutely fantastic for the interpretation of this objective now that's interesting I thought Tess was more or less limited to closer objects it can actually do observations of this star I wasn't aware that yeah it well it takes them an image of the whole sky every 30 minutes and that's that's downloaded back to earth so even though these targets are generally not because this is a faint star so it's generally not going to be what we'd call a primary target for tests those are the stars that it records data of once every let's see every 2 minutes is the cadence normally for the primary targets but for the for the full sky it's basically saving a stacked image every 30 minutes and so therefore what you can do is you can download those images and reconstruct her own photometry from them which is of course why they actually decided to do that they thought it'd be helpful to the community who were interested in those fainter stars so it's something like 200,000 primary stars which are being observed by tests but about 20 million stars which are observable in full-frame images such as I think this were such as the Kepler field most of those kept objects would be doable I think from tests so especially if you're talking about a dip of 25% or 20% like there's really big dips that's going to be detectable by tests no problem say we don't know if that's going to happen again if it's going to coincide with the test observations but there would definitely be data on Tybee star recorded by tests there's also the last aspect of it's particularly strange about the story said it seems to be or at least last year it seemed to be dimming over a long period as well as the short-term dips has anybody done any modeling or tried to figure out what that long-term dimming trend actually is within the context of this phenomenon yeah I mean in a in a Columbia University here my colleagues have been thinking about that this is Brian Metzger and Nick stone they actually did do a video on our channel talking about their idea it was the idea of sort of a planet in Goffman in so the star had a massive planet come nearby it engulfed most of it and totally disrupted what was left over and that totally disrupted material is still in orbit of the star and that's what gives us these occupations and the fact that the star swallowed a planet raised its luminosity at the time and since that time it has been slowly sort of stabilizing returning back to its normal luminosity so that kind of explains both aspects of this problem the secular decline as well as the orbiting material but of course it's kind of unclear how often you'd get this situation in the first place and it's challenging to to confirm this observational II as well but I was kind of a fun idea that we we had in the department about that indeed indeed and on that we must go to break I'm joined today by Professor David kipping of Columbia University and when we come back we're gonna talk more about exoplanets tests transiting exoplanets and even exomoons and the possibilities for life on such places Joan shouldn't we be fulfilling a traditional end-of-year directive and wish the audience something about their holidays yes I know I was getting to that but I did have a thought we talked about the future quite a lot I'm interested in what our viewers opinions are on what 2019 will hold ah leveraging a collective mind to predict the future John this is an interesting concept I don't make for a nice season finale I'll do a special bonus show reading them off and speculating and next year we can see who was right if you're still finally some peace and quiet so what do you think 2019 holds in store or how about the near future beyond that or the far future make your predictions in the comments below for the holidays will be releasing lots of bonus material from past guests that you haven't heard before plus more original content for me and we'll be back in January with more interviews and we're back with Professor David kipping a professor now you do a lot of work with exoplanets which is probably the most exciting field within with an astronomy because just the instrumentation is getting so good and we're gonna be able to reach so much further out there look at the characteristics that some of these exoplanets exhibit and we might even find one that looks a little bit like Earth or even one that has something weird like strange oxygen levels that you know or a vegetative red edge or something like that do you think over the next 20 years what do you think the advancements within studying exoplanets are gonna be do you think we have any real chance of seeing evidence of no matter how simple it is but photosynthesizing EXO life yeah that's it that's a 64 million dollar question I suppose that's what you when we look for exoplanets I think sometimes we forget and that that is ultimately the driving reason behind why this field is enjoying so much publicity so much funding and so much interest and the reason is because people want to know are we alone in the universe is there life out there so I think it's um sometimes you hear people astronomers colleagues who say I'm not interested in like who cares about how saying I kind of get that it can become a bit exhausting when that's the only thing you kind of get asked about all the time working on exoplanets but it's also the main driver behind ultimately this quest that we're on why are we finding all of these planets what's the point of it unless we're trying to answer some kind of fundamental question and this is one of those types of fundamental questions so in terms of the future as you know we have the James Webb Space Telescope coming on soon and lots of people are excited at once it finally gets into space and hopefully works no problems but people are very excited about the possibilities that that might be the first mission which has a chance a thin chance I think but a chance of possibly being able to detect the signatures of a biosphere the signatures of life the great challenge is I think the you know detecting the product of photosynthesis or what is that that's oxygen and the actual Oh to line itself is quite challenging to the text but the ozone which is a byproduct if you have oxygen-rich atmosphere is much easier to detect that has quite a strong signal to noise potentially if you have the right type of target so imagine a very bright star very nearby to the earth and hopefully even a small star so that when the planet transits in front of it we get a giant boost in terms of the signal-to-noise that's because if the earth transit so much smaller star the transit depth is increased by the square of the ratio of radii of this star compared to the Sun so we we have a chance that if we do have a really good target like that maybe James Webb could smell ozone in the atmosphere it would take a lot of James Webb time it would probably take many many many hours and orbits of the planets around the star and hours of target time with with James Webb to acquire the signal is an episode to do that even in this kind of optimistic scenario and then let's say it it succeeds in doing that then does that definitively prove life exists on the planet so it was Proxima Centauri being for instance is probably one of the prime targets although that doesn't transit unfortunately but a target to kind of like that in that case we can't be a hundred percent confident that what we that the detection of say ozone implies life there are abiotic processes which can create atmosphere such as the photolysis of water which is when UV radiation basically splits water up and creates oxygen in the atmosphere so it's especially around an M dwarf where the ultraviolet radiation is not that well understood and the long-term variability of stars is not not well understood for those types of stars it is quite possible that they may be oxygen-rich but there's nothing living there it's just a product of this photolysis and in fact maybe even that high radiation environment is sterilizing the possibility of life on the surface and so these are these are very challenging questions and I think there has been a movement recently away from maybe being so focused on individual objects to thinking about the overall population maybe we will never know for sure for 100% confidence that exoplanet B or C or D over here has life on it not unless we visit it and actually you know land on the surface and pick it up and scoop it up in our hands although even even then it's questionable whether we would actually know whether life's on the planet or not but even putting that aside probably what we're going to be left with is a population of planets of which say 8 out of 10 earth sized planets at the right distance from their star for life show ozone and maybe we can interpret that the fraction of stars which we would expect to lead to a biotic production of ozone atmospheres is nowhere near that number and thus even though we don't know which of those eight out of ten definitively have life we can say definitively that some of them must have life because there's no way you get this number of detections just by chance so my guess is that will be the the most confident thing we'll be able to say about the detection of life in the future on what timescale that occurs it's probably longer than James Webb because James Webb my PhD does for one or two but it's not going to be able to do it for dozens of earth sized planets so therefore you probably need something like Louvois which is a proposed mission in the future there's no security funding for that right now or something like at EPF that was talked about in the past image planets directly block out the star nationally collect the atmospheric information directly from the planet one of those very expensive tax emissions might be the only way that we gather enough earth-like planets to really have a conclusive remark as to whether we're alone in the universe or not and we must take another break so I'll be back in a moment with dr. David giving be sure to LIKE subscribe and share the video if you're enjoying our videos and wish to support us in a more personal way check out our patreon page linked in the description below and now back to John and we're back with dr. David Kipp a professor we talked about biosignatures and the possibility of detecting those with coming instrumentation like James Webb but there's also the elephant in the room that people talk about techno signatures one of them being if you saw like CFCs in the atmosphere of an exoplanet now I imagine that's probably going to be lottery odds to catch that but it seems to be with just within the realm of possibility what do you think do you think that there's any hope for James Webb of detecting something more than simple life in the universe I think tender signatures is there's a really interesting approach we've I think it often Connie gets put in a bucket of almost like the crazy bin in terms of how astronomers perceive it like it's so outlandish and so fringe science that it doesn't get much attention it is almost a way a rebranding of SETI as well the search for extra strong telogen but it's kind of broadening it out SETI is traditionally focused on radio communications and tetanus signatures takes a broader view of it that you know just any kind of signature not just radio transmissions any kind of thing that your civilization might produce that we could potentially detect I think it's if you're talking about bio signatures I don't think it's unreasonable if you're going to talk about that seriously you have to talk about techni signatures seriously especially because what excites me about technical signatures is it's unambiguous if you detect ozone in a to the planetary atmosphere as you've already spoken about it is not an ambiguous there are natural abiotic ways you can produce that if you detect a prime number sequence being community transmitted across the stars by a high-powered radio or laser transmitter there's nothing in the universe which naturally does that we know that or in it with very very high confidence so that's what to me it's so appealing about techni signatures is that there is just no doubt if you detect that it's you've won the lottery I mean of course the big challenge is how often does that happen in the universe it you would think it kind of has to happen at least less often or equal to the fraction of biosignatures out there because presumably every tangible civilization was born from a biological civilization at one time in the past although I suppose as possible these things could have spread out and colonized a very wide number of stars by this point so it certainly seems not an unreasonable experiment to try and conduct whether James Webb would be a suitable mission for trying to attach that I think the chance of you writing a proposal to search for biasing techno signatures with James Webb and being accepted is infinitesimal it's just the climate of the field is not lukewarm enough in any sense to consider proposal to search it's just too expensive emission it's a ten billion dollar mission every second of telescope time is it's very precious to them so they are not unfortunately they're not going to use the time to do that kind of science so the best way to detect a techno signature would be in surveys so James Webb is not a survey telescope it will look at individual stars or individual fields whereas Kepler surveyed two hundred thousand stars simultaneously Tess is a survey monitoring a similar number of stars across our sky Alice's T in a future will monitor something like 10 billion stars and gaius in Li has monitored billions of stars so if you can think of a way that a civilization might betray its presence in one of those types of surveys then I think you have not only a much larger sample of stars to interrogate your hypothesis but you're not going to come up against this boundary that nobody's going to give you anytime some telescope to do it because the date has already been taken it's already observed it's in the archive and you can just go through and look for it so I think that's going to be where tennis signatures you know is focused on for the next few years maybe we start seeing really plausible candidates we might start getting time with James Webb to pursue them but right now I can't see happening to do a blind first protect their signatures but you're not going to get a good time to do that which I mean it has to be said that we are a techno signature producing civilization so clearly it can happen just maybe not very often so it's by looking at surveys it'll be things like you know like how Teddy star was discovered just serendipitously in a survey particularly the LST is interesting on that because that's looking at a you know what is it every day and a half or something like that it takes a whole sky survey I guess one of the most unambiguous techno signatures would eat lasers if you saw laser communications or something like that what other unambiguous ones are there there you have lasers you have radio signals but those don't really seem to be all that unambiguous what else is there yeah I mean I think these alien mega structures if they had specific imprints they could be essentially impossible to explain naturally you can imagine you know like I said like the leucon or giant triangle triangles just do not form in nature like he just didn't find them in the sky there are no triangular planet stars or galaxies out there so you're if you see something like that it really does imply something artificial in terms of the transit method which is something I'm probably most familiar with there are you can even use the lasers to do this we argued in a paper a couple of years back much cheaper we think that the moment of transit is kind of a special time it's a time we know where when we see a planet transit that if there was a civilization on that planet they would be able to predict when week see them translate it should be a fairly straightforward calculation and likewise it's straightforward for us to calculate when the inhabitants of say Proxima Centuri because the Earth's transit in front of a star see Proxima Centauri B is not at the right inclination to see s transit but in principle we could do this for any star which we calculate when it was C s transit so that moment is kind of special because it's a time that everyone in the universe can agree upon as an ambiguous special event that's happening from the in the system and there's also an interesting time to observe the system because you you know that this is the opportunity to smell the atmosphere of the planet for example using transit spectroscopy so we've been arguing that this moment of transit is what you call a selling point which is an idea from game theory it's an idea of if you can't communicate with the other players of the game how do you agree upon a single location to me or a single medium of communication and a shelling point in possible ETI communication I think would represent the transit the instant of transit now that might mean they are posting some laser at us at that moment in time a very specific pulsing or frequency that we are not yet looked for or a community radio communication at that time but I think exploiting the astronomical shelling points that are presented to us is is helping us to deal with this haystack problem there are just so many infinite number of radio channels to search through so many infinite number of possible moments in time to look at that we need to somehow narrow down when to look for these techno signatures as a way of improving our odds of success it doesn't mean you should ignore the other times but it means that you might want to add a little bit more priority to the observations at those special times so one of the other things that Arnold noted in his paper was a louver you know you could have something really unnatural even worse than a triangle really this seems like a cheap way to announce to the galaxy that you exist cheaper than building a you know omnidirectional radio beacon blasting out you know the hydrogen line or something like that but if a civilization did that they built something that says we're here could you actually communicate visually could you send data to another civilization across you know space by using that visual method the louvers and things like that or would that just never be decipherable you could it would be it would be a very low information transfer rate of course you know limited by the speed at which you could move these giant structures around I'm not convinced personally that this is necessarily an economical way for a civilization to go around announcing itself to come back to this you know the this paper that we wrote a couple of years ago we think I see the laser that lasers are a much cheaper way so just during that moment of transit you fire a laser at whatever star you're you think might be observing you and you could either distort your transit to look very peculiar you know inverter scooped it do edges sketch in the middle and do like the Manhattan silhouette or whatever you want in the center of that transit and probably the most artificial thing you can do to your transit is to make it a pure box which you're easily able to do with a about a 10 megawatt Aiza that sounds like a lot of power but it's absolutely nothing compared to my have energy you need to build a giant mega structure around the Sun so we argue that this is an appealing method because you can make extremely artificial looking transits and then if you more carefully monitor the laser beam you could post it you could modulate the frequency and do very high data transmission rates down the laser beam itself so I think it would be more appealing to use optical laser emission or something rather than building a giant structure because you really can only announce yourself for that you can't actually carry information or these significant amounts of information now that that of course segues into a paper you once wrote you could also use lasers to cloak your planet from others how would you do that so this is kind of the extreme end of the scenario but I mean a planet transiting a star is essentially a dimming of the star right that's that's what an observer would see they see the planet below out some of the Starlight for a short amount of time so you could cloak that transit signature if you so chose to just by creating an equal and opposite brightness increase at that moment in time and because you know which observer you're trying to mask yourself from then you could just use a laser so that the idea of using a laser is that it's it's very narrow band right you can just directed a single target unless it requires far less energy then trying to do across the whole sky you could equally do this across the whole sky if you had that requirement it would cost a gigantic amount of energy to do that but it's fairly straightforward you can do it with 19 like at current technology you can do it you could basically have these sweeping super spectrum lasers which can more or less match the exact spectrum of the Sun and just create an equal and opposite brightness and direct it towards the nearest habitable planet at the very rare moments when we transit in front of the Sun as viewed from their perspective and it would cost you almost no energy to remove your transit signature and you go Union go further than that we talked about how that would become peculiar because you'd still detect the planet in other methods maybe for example the radial velocity method you'd know there was a planet there but it doesn't seem to transfer and maybe you'd even think that it should transit for some reason then what you could do is keep the planetary transit there but just mask the bio signatures with one of these lasers so you could just make the atmosphere look sterile and dead wanted to as well just like a giant hydrogen envelope or whatever you wanted to so it's there's certainly games you can play I guess the reason why we wrote that paper was to point out that this is just a toy example if you like of how we may not be as smart as we think we are we think we can detect an alien civilization across the stars but if they want to hide from us they probably can and maybe this is not the method they choose to hide from us but pretty much any any method we're using to detect planets or some other atmospheres it's not unreasonable to think there are certainly means of evading a detection unless we that can't you know when you think about houses to statistically interpret the no results of such surveys it's an interesting idea because if we detected a techno signature really really powerful one that said this is an extremely advanced alien civilization that's 20 light years away we might we might want to think about cloaking earth if we were in their line of sight as far as transits go and on that we are out of time professor thanks for joining us today and I hope you come back yeah thank you for having me historically first contact between peoples on earth rarely goes well this may also be the case for very different species in the galaxy entirely alien to each other there would be few commonalities as far as communications go at least initially and it could turn out that visibility in the Milky Way is inherently dangerous distance mitigates the somewhat most of the galaxies can't know about our technological civilization which has been visible only about a century and there seems little point in traveling great distances just to go into conflict with a civilization that requires a lot of energy but what if someone were discovered very close say within the 100 light year radius where our civilization is visible to others the question here is should we worry about cloaking earth unfortunately the presence of oxygen in our atmosphere has informed the entire galaxy that there is a biosphere here and anyone close may already know about us so hiding may not be an option but with our improving ability to detect odd phenomena in the universe there may come a day where some strange feature a light curve ends up being artificial in nature what they might be like or even if contact can be established at all is a matter of pure speculation but if we do detect such a civilization should we announce ourselves and say hello and on that note next week hey where did these dice on the rearview mirror come from I kind of like him John did you think you could hide from me by doing the rest of the show in your car Ana where is the labyrinth computer voice back in 1985 where he belongs John oh and by the way I've had a few upgrades installed into the car wait what it's now completely driverless [Music] [Music]

Channel: Event Horizon

Views: 132,988

Rating: 4.8574367 out of 5

Keywords: KIC 8462852, megastructure, Space, David Kipping, tabby's star update, tabby's star documentary, tabby's star, event horizon, event horizon john michael godier, godier, tabby's star 2019, tabby's star update 2019, cool worlds david kipping, tabby's star structure, picture of tabby's star, alien, alien megastructure, columbia university, cool worlds lab, boyajian's star, what tabby's star looks like, kic 8462852 tabby's star, The First Image of Tabby's Star Structure

Id: qgkuXtQ5f9I

Length: 44min 43sec (2683 seconds)

Published: Thu Dec 20 2018

Reddit Comments

[u/SpartenJohn]

The first image of the structure dimming KIC 8462852 or Tabby's Star. Using 1D data points to create a 2D image to reconstruct an image of whatever it is that causes the dimming of Tabby's star, by Dr. David Kipping and Emily Sandford of Columbia University.