Why the Solar System May Be Full of Life with NASA Chief Scientist Dr. James Green

where do we go from here since the dawn of the space age the scientific exploration of our solar system and the universe at large has been one of steps from increasingly large more capable telescopes to exploratory spacecraft that can perform tasks remotely on planets like mars that only a few decades ago were almost out of reach each new step in advancing our exploration of space takes us to a new set of steps much like a choose your own adventure story a process likely to never end if we move on to explore other star systems as nasa chief scientist my guest today helps guide that process of taking new steps including the exploration of places like mars and titan with new probes that will no doubt yield new findings that will lead to new steps in the process of understanding this amazing universe in which we live you have fallen into event horizon with john michael gautier [Music] [Applause] [Music] in today's episode john is joined by dr jim green dr green has served as nasa's chief scientist since may 2018 before that he was the director of the planetary science division at nasa headquarters under his leadership several missions have been successfully executed including the new horizons spacecraft flyby of pluto the messenger spacecraft and mercury the juno spacecraft of jupiter the grail spacecraft to the moon the dawn spacecraft of vesta and ceres and the landing of the curiosity raver on mars dr green received his phd in space physics from the university of iowa in 1979 and began working in magnetospheric physics branch at nasa's marshall space flight center in 1980 in 1988 he received the arthur s fleming award for outstanding individual performance in the federal government and was awarded japan's katani prize in 1996 in recognition for his international science data management activities he also recently received the nasa exceptional achievement medal for the new horizons flyby of the pluto system jim green welcome to the program well thank you very much it's great to be here now jim it is one of the most exciting periods in my lifetime for nasa right now we we've returned to space from american soil and we have successfully launched the next in the long series of mars rovers perseverance and perseverance is noteworthy because it has sort of a legacy on it years ago the planetary society attempted to send a microphone to mars here are the sounds yes and unfortunately the probe that it was on failed so we never got to hear mars finally we're going to get to do that what can we expect to hear from the mars microphone well actually there's two microphones i really wanted in this mission uh one because i was head of planetary at the time and and uh was helping define and move forward with what has now become perseverance i really wanted to have the opportunity to revive that concept that the planetary society was so passionate about and i was too the ability uh in an atmosphere as the wind blows as the soil freezes and heats up and goes through cycles and and the in and the sounds that may occur particularly as the rover moves was really important to do and so the two microphones that we have one we would call an engineering microphone it's on the body of perseverance and that's designed to pick up sounds and those sounds would be used from a perspective of how well the rover is operating you know it you know it is it moves um over the surface of mars we're going to hear the creaking and cracking we're going to hear the the the moving of the wheels and we want to be able to hear the sounds of the rover operating as it naturally would you know and if we hear variations of that later on that may give us a hint that something is wearing out whether it's metal to metal or the actuators are running out of lubrication you know something may happen that gives us the heads up that allows us then to plan around it and to preserve the resources that that we've put so hard worked so hard to put on the surface of mars now the other microphone is associated with mass cam so it's it's on top of the of the of the long neck of the rover of that mast that sits up and and to give you an idea how high that is if i am i am 6'4 if i stood next to perseverance and and looked right at mass cam my eyes would be right there so actually the top of the rover is just a little taller than i am so the the cameras that are taking images of the surface of mars from mathcam are actually at eye level and so you get great stereo viewing just as if you were standing on the surface yourself and of course now we've got the microphone there now a microphone lower down on the body and then uh you know three or four feet taller up on the mast one may or may not expect to hear things differently but because the atmosphere is so thin even variations in the pressure from the surface up to several meters high may indeed give a slightly different variation of the sound so i'm real excited about having the opportunity to not only have those two recording at the same time but be able to compare those and then of course i don't expect at night as the rover is sitting there maybe munging and doing a number of things with the data it's collected during the day i don't expect it at night to hear crickets okay no pun intended but the concept of being able to just sit and listen to sounds from another planet it to me is just really uh you know energizing it's just really exciting i'm just invaded breath because we don't really know what we're going to hear can you predict what we might hear i would expect that sound doesn't really travel as far on mars as it does here i could be wrong on that but say a dust devil or something like that hits the rover which used to happen with uh spirit and uh yeah right so say that happens what would we hear what do you what do you think we would hear well there's a good chance we'll hear it and the reason why is uh not so much the the it's talcum powder like consistency for the dust not so much that you you know we're gonna hear it you know hitting hitting uh the wheels or something low but indeed um it'll hit the microphones you know and we'll we'll hear these little specs the the range of how how far around we would hear that is going to actually depend i think on the wind velocity so what do we know about the wind well we have weather stations on curiosity you know and we have also weather information pressure temperature from wind speed from insight you know we've been collecting this data for long periods of time and we've actually developed global circulation models of mars you know where we actually can predict potentially how extensive dust storms can be once they get started we can see uh diurnal cycles in temperature and pressure you know the change from winter to summer there's a pressure wave of of carbon dioxide that blows over the planet during these time periods we're going to be able i think to hear some of those phenomena and we do know that the wind can be pretty brisk it can be up to 125 miles per hour okay but the pressure is so low that's not enough to straighten a u.s flag sitting on the surface for instance so the uh the rules are different in that rarefied atmosphere for winds but it's still enough you know you say that the talcum powder like dust it's still enough to envelop that planet in global dust storms occasionally oh yeah oh yeah absolutely when that happens would we hear anything uh yes and no in the sense that um dust storms on mars you know are are not like what mark watney experienced it's just not gonna happen all right they can go global uh they can uh move quite quickly they can envelop the planet but what happens is it it primarily starts out at relatively high altitudes and and it just it it's like all of a sudden over time the sky starts to dim because what's happening is as the as the particulate matter is the dust it's suspended at higher altitudes it's reflecting that sunlight back out into space and so consequently you know you can you then see that the day turns gradually into dusk and then of course if it's really bad it it gets very dark all right our imagers see that spirit and opportunity saw that come and go you know they went through a couple dust storms uh opportunity did and the last one actually is what took it out dust storms can occur every southern summer okay so every 680 days or so in the southern hemisphere uh mars is an elliptical orbit uh puts it at a point at a place where it is closest to the sun and that that ends up heating uh the planet in such a way that the dust can get lofted and then and then actually uh move outward uh from from where it may originate and so then the dust eventually will settle out and we'll hear some of that settling we'll hear some of that dust coming down and as i mentioned we'll you know we'll be hearing that i think as it as it uh may get close to the mic or touch the mic as it as it falls out of the atmosphere you know always our big worry was uh you know when we landed spirit and opportunity you know they would be there for 90 days because we knew the atmosphere was so dusty that over time the solar panels would get uh clogged and then we couldn't power the battery and then uh everything would shut down but of course the atmospheric dynamics which we didn't really understand very well at the time kept those two rovers alive for you know for many many years opportunity going into its 13th and 14th year pretty spectacular intended originally for only 90 days well that's only because we we were pretty ignorant about the total environment it was going into but now we know well even still though i mean that's a lot of traveling for a rover 14 years and as i recall didn't spirit actually wear out and have to drag one of the wheels yeah it did it did but it is still a testament yeah oh absolutely it's a testament to our ability our imagination and our ability to understand the system so thoroughly that we have landed in its capability and its assets with a team of diverse uh people that can come up with really creative ways to keep things going to keep doing science to keep making something happen for the agency and and you know nasa is known for that nasa's been doing that forever you'd be shocked at how many times uh you know uh the the the group managing the voyagers reprogrammed you know a piddly amount of memory to make it do the spectacular stuff that it was able to do you know those are technologies when it was launched in the 70s that really came out of the 60s okay and so we're talking about really primitive computers with hardly any address space you know not not huge memories you know it just just uh really know you would you would never even consider using a computer and capability like that today it'd just be forgot it you couldn't you couldn't you couldn't stand it but we made those things work now long term we have curiosity and now perseverance and these are nuclear powered essentially they they have rtgs that runs them so they don't need the sun or solar energy on mars now we have other spacecraft where we've used this notably voyager which decades later we still hear from yes long term say these rovers last years and years and years longer than what they originally were were intended to ultimately you're going to lose energy from the decay of the power supply right so is there a way to work them like voyagers you know turn them into um you know stationary you know platforms and things like that and keep them going for decades and decades well there is of course still that limitation so just to contrast the two solar arrays require the sun and the spirit and opportunity had solar panels and that that took that sunlight and charged up a battery and then the battery ran the experiments and then over time as the battery went uh ran down you know they would change its operational scenario they would change you know if this set of instruments were making measurements that were real power hogs we would do that only at a time when the battery was fully charged and only in the right places and then there were times when okay we're going to winter over so how we winter over is we will take local measurements like like weather information for instance because we can do that without moving arms and and a whole bunch of things but we're going to have to find a hill drive up the hill such that the sun can shine straight on the panels and get maximum amount of energy out of the sun so that power management you know was really active well in a similar way but not so intense the radio isotope power capability on on curiosity and now perseverance enables the rover to not require the sun how that works is we have plutonium-238 which as it decays which means that the nucleus literally explodes in and from uranium it becomes other elements and one of the other elements it become becomes is a is a helium nuclei which which then as those explosions in the atoms occur they hit a thermal couple which then uh heats up you know so these these uh the this accumulated uh uh plutonium it glows red i mean it's just constantly decaying and so that thermocouple heats up and then we take the the temperature difference in the thermocouple and allow that to have a voltage difference which then is used to of course charge the battery and the battery is used to run the experiments and so we know the decay rate of the plutonium based on how much we have available and we'll start out with 110 or 15 power in the in the rtg and it will decay a percent or to a year okay predictably all right we can calculate that and we know it and we measured it and that is exactly what happened so so long as the circuitry and everything is healthy we can keep charging up that battery it's just like having your cell phone plugged into the wall all the time now when it gets down to a certain level maybe in 5 8 10 years you know on that order well beyond its expected life of just a couple years it will do power management we will run the rover in certain ways run experiments in certain ways allowing the battery to charge up and then put it back into operation and that whole process works really well another thing that we do is we keep the battery warm now the temperature on mars is really low the average temperature is 40 or 50 degrees below zero that's the average temperature okay so it's pretty cold and it may get up uh to 40 or 50 degrees you know during the day in and around the equator you know when the sun directly overhead so the temperature will will change by you know 160 degrees fahrenheit a day you know just huge variations in the temperature and and so that's really hard on everyone in particular so we use a wonderful insulation and that insulation is aerogel we pack the battery in aerogel okay now that's the same stuff we used when we when we uh had um you know our comet flyby you know stardust where where stardust flew through the coma of a comet picking up dust and putting it in the air gel and then we enclosed that aerogel brought it back and it's sitting in our laboratory at the johnson space center in our extraterrestrial curation facility where we then extract the dust grains out of the aerogel and analyze it but it turns out to be this spectacular insulator so aerogel is also ridiculously light right yes so you can save a lot of weight simply by using that as your insulation as opposed to you know i don't know fiberglass or something yeah we love it yeah it's it's tremendously versatile now there is another aspect of this mission that's absolutely amazing ingenuity yeah we are going to have a little tiny helicopter operating on mars now this is a technology demonstration fundamental yeah i realized that but so was you know long ago so joiner little tiny rover just showing that we could have rovers on mars and look what we have now so maybe in the future much greater things will come from what we learned from ingenuity what is ingenuity going to do so you're right ingenuity is a technology demonstration this is the first time we'll ever attempt flying anything on its own mobility in an atmosphere of another planet it's a pretty spectacular concept and if it works indeed as you say it will open up an enormous number of doors ingenuity is bolted to the bottom belly pan of perseverance and after perseverance lands it will drop ingenuity on the ground okay and then drive away going probably you know 50 75 meters away and then command ingenuity to turn on now ingenuity you can imagine a um a little box like a a cell of a cubesat you know maybe maybe five or six inches by five or six inches by five or six inches now a nice little square box in that box is battery and a camera capability with the radio capability to then take data store it and then send it back to the rover okay send it back to percy and of course run these two blades and their long blades are about four feet in length that are connected like an x and they counter rotate and because of that counter rotation you don't need a tail blade and so we're going to run that at at an enormous rpm revolutions per minute and then once we give it the command to turn on we're going to perform a series of maneuvers the first one is a simple one it's go up several feet you know five feet or so and hover and then sit down very simple you know just rise and come down and and once it does that then it's going to telemeter all the information all the images that it took back to the rover and then the rover will take that and send it back to an orbiter we have orbiters that are going around mars and then from those orbiters there are relay orbiters they're going to send that back to earth that's how we communicate with assets on the surface and in that way we're not we don't have percy uh or curiosity for that matter driving with a big trailer and a big dish behind it you know and pulling the trailer all right and so that we had a dish that we can send anything back to earth we use the capability of our orbiters to be the relay so then we'll charge up the battery you know while we're analyzing the data back at the ranch you know back at jpl and and take a look at it and then we'll decide okay we're ready for test two so test two test two will be uh once again we're gonna pick it up but then we're gonna translate we're gonna fly parallel to the surface for maybe 10 meters or so and while we do that it's going to be taking data in images and then we're going to set it down so it'll form this u shape all right and then we'll send that back through the orbiters as i mentioned before analyze it and then the next day it will charge it up now we're ready to go the next thing is indeed we're going to now take off if all that is working we have all the fundamentals ready to go we're now going to put it through uh even more strenuous tests so we're going to then fly up go then at a particular height you know maybe 10 feet or so we're going to take off and we're going to go 50 meters maybe more and then come back and then land exactly in the same place that we took off you know and so those are a series of tests that we're going to perform at the end of those tests and there are a couple others that are similar to that at the end of those tests we're then ready to put the helicopter into service and okay so what kind of service are we talking about well one of the toughest things to do about driving rovers on mars is to chart its path okay there's no roads on mars obviously but indeed there there are valleys there's hills there's sand traps you know that means there's craters that have occurred for which the the dust has flowed for you know uh millions of years perhaps and filled in filled in the crater we can't even see seed that it would collapse into it if we drove into it this is what actually happened to opportunity by the way and so consequently then i'm sorry spirit uh so consequently then we want to be able to get high-resolution images in a direction that we expect the perseverance to go and so ingenuity could provide that for us in and that's what we'd like for it to do once we do that you know then we know this kind of technology has a bright future on mars i can imagine a future for which we would have a series of helicopters much more capable much larger landing we could drop them off in certain areas and then also have a relay station for which then these helicopters can go you know enormous distances and and then radio back information which then can come back now one of the one of the features you know that we have on mars is what we call a reoccurring slope linear these are regions on the sides of craters for which we believe during certain times of the year water will flow down well the pressure's so low water doesn't stay liquid for hardly any time unless it's really briny and we believe this is kind of briny and it will last now for many minutes and so water will flow down the sides of the crater and then eventually evaporate and that happens during the summer when the the sun is shining on the sides of the crater and what we think is happening is there's underground aquifers and these underground aquifers it's so cold that there's an ice plug at the end of them and when the sun shines on them that eye sublimates and the water pours out down the crater wall wow that's spectacular you know how can we how can we look into these aquifers how could we make measurements and see if there's methane you know with another indicator of life that may occur in these aquifers if we can get to it the only way to do it is in these craters where the rsls are that we can go up with a helicopter and look right into the origin of these streaks that we see on the sides of the crater and that's what the helicopters could do easily now that is liquid water which brings us to our next topic to tackle life on mars past and possibly even present because if you've got an aquifer with liquid water flowing through it anything that may have once lived on mars surface may still be there right right that's right so do we think life is on mars in the in the past well one of the things that perseverance is going to do is to go to a region where we have high confidence that there could be signatures of past life and that is jezreel crater now jezreel crater is an impact that occurred billions of years ago and that impact occurred at a really unique location and that location is a place where water from rivers flowed into the ancient ocean of mars so it this crater this impact occurred right at the ancient shoreline when mars was a blue planet we know enormous amount of water flowed on mars two thirds of the northern hemisphere was under water and in some places more than a mile and a half deep and and something happened the climate changed rapidly the water started evaporating and now mars is this arid world we see so by going to jezreel crater right into this area where the water flowed bringing sediments from large number of regions out on the plateau into this crater and building them up creating a delta and now we can see that delta from orbit it's huge it's enormous in that particular area we believe is a great opportunity for us to interrogate dig down get some samples bring them back and see if there's any signs of ancient life on mars now the analogy of that of course is here on earth we've gone to ancient dried up river beds where there are sediments laying there and we can dig into those sediments and we see evidence of microbial life so the sediments have been preserving life past life on earth and and the concept is that's probably what it would do on mars if we could get into this place and look deeply into these into these sediments into these deltas space is full of mysteries and nasa's spacecraft are working hard to unlock them what are scientists finding out how do they do their jobs dr jim green nasa's chief scientist leads discussions with some of the leading experts in planetary science and other fields to give you a guided tour of the solar system and beyond in his podcast gravity assist dr green also explores how scientists get inspired to pursue careers in science that gravity assist that leads them to become the explorers they are today head over to nasa.gov forward slash podcasts to listen to gravity assist or hit the link in the description below and now back to john with dr green now the geology of that when when we're we're gonna take samples and cores and things like that how do we get them back here is there any sort of plan in the works on how we might get those samples back here or what can we do in situ with the instruments that are already there at mars well we have a whole series of in situ instruments and they're designed to help us pick the right places to be able to take the samples for instance right at the end of the long arm where the core is this is where we'll core rock right at the end of that arm are two instruments they're sherlock and pixel now sherlock is an ultraviolet spectrometer and it's designed to study the mineralogy and the chemistry particularly right at that surface that says hey this looks interesting let's drill here and it has a fabulous camera associated with it called watson you know what else would you call it if the instrument was named sherlock and then also there we have an instrument called pixel now this is a x-ray spectrometer and it's designed to zap an area which then the matrix in the minerals that are sitting there will glow back and that'll give us a lot of information about the chemical composition of the rock and so with those two sets of instruments working in tandem we then can see hey this looks like an exciting place to drill and then we drill and we create with a with a a cylindrical drill that creates a core now that core looks like a one of the big crayola crayons okay a nice big sample and and we break it off and then it moves through a system for which we then sleeve it we put it in a in a metal sleeve and we may hold on to several of these until we get to a place you know where we're drilling several locations in and around where the rover is hang onto them for a little while and then if we decide okay we're pretty pretty thoroughly examined this area got all the mineralogy and samples we think we need we're then going to drive off to another area we dropped the samples we dropped the samples for later pickup okay now in addition to the the instruments on the arm the rover's got a bunch of instruments you know there's um a laser uh on the very top of the rover it's called super cam and this laser then blasts rock okay it literally vaporizes it for which then we take us a spectrum of it and we get a really good idea as to its overall composition before we even go over to that area and we can do that from 20 meters away and so that's a great instrument in addition to the cameras that we have we also have a ground penetrating radar so as we see the stratigraphy underneath the rover change we then get an idea of of the setting of the rock record that we are creating in the in the caching system so uh if we then move from place to place and we have actually uh more than 40 uh we have an opportunity to drill more than 40 of these cores and lay them in piles over time we want to thoroughly look at this particular area but meantime back on earth we're developing an next set of missions to go get them okay so what do we need to go get them well we're going to need a fetch rover you know we're going to need a real rover we can sit down on the ground that that its job is to pick up the sticks okay to take off uh and go and go to these piles and acquire the samples in these sample tubes in these metal sleeves that we put them in and then bring them back to uh another system that will land on mars that contains a rocket a mars ascent vehicle a mab if you will and then uh that mav will be laying down on that side and we'll feed those samples into a particular area and once that fetch rover is brought in all the samples that we believe we need then we're going to erect the erect the rocket blast it off the surface of mars and put those samples in orbit you know so it'll have a couple stages perhaps it'll get up to maybe 400 kilometers you know all these things are things that we're looking at studying and then and then drop a a a big ball uh that contains all these samples inside this ball and then it'll just sit in orbit now another mission is going to get into orbit around mars and hunt that hunt that sphere down you know literally get into orbit match its orbit with the with the samples that are orbiting acquire it and then and then break orbit come back and drop it off here on earth and then they're here and then it'll go into a facility where we'll study the samples in a highly contained biological containment facility they determine that these samples are safe not only to open to study but uh but to let other laboratories look at them other organizations with tremendous capabilities to study this rock wrecker and be a bio level four facility is probably what we're thinking and so that will begin that analysis period of really understanding the origin of mars how it's changed over time aspects of climate change from the rock record you know our rock record here is you know is the geological history book well we're going to be bringing some of that back from mars and we may even be able to see samples have some indication of past life on mars perhaps even plant life you know which was some of the first things that happened here on earth all amid the apparent coming human exploration of mars so we could end up nasa could do a repeat of the apollo mission that visited one of the surveyor spacecraft and brought a camera back so you may end up with like a mast cam back or something from humans on mars too yeah that would be pretty slick definitely it's definitely one for the smithsonian now one of the more tantalizing clues that mars shows us are the methane blooms yeah and could be geological but could be biological is there anything on perseverance that's going to increase our knowledge of those no perseverance but there certainly is on curiosity and you know curiosity is very healthy its rtg is still cranking out a lot of power the instrument called sam which is a sample analysis on mars instrument from goddard space flight center is working perfectly that's the instrument that is involved in you know sniffing the atmosphere and that's the one that has seen the the the methane increased so methane is what we would call one of the atmospheric life gases okay so is oxygen so is free o2 and we're measuring that too by the way we see the o2 pica just like the methane does during the summer and then start dying away you know during during the fall and winter months but the oxygen is being depleted far faster than the methane does so we don't know what's generating the oxygen and we don't know what's depleting the oxygen it is a real puzzle so these two life gases could be generated by biology it could also be generated abiotically which means not by geology but it's it's giving us really exciting set of information about the potential for current life on mars now with those two gases though the oxygen and the methane being is is it sort of less likely that both of those would be produced abiotically at the same time by the same process presumably so even though we don't know how the oxygen is being generated we do know because of the season you have a couple things in play well here on earth you get into the spring and the summer and everything just seems to take off and grow you know that's a there's you know you got the bloom of the of the season associated with the plant life on mars what happens is uh as you get into that season the temperature is warmer the temperature is warmer and there's water in frozen states underneath the soil and that warms up then then perhaps the barrier where this gas is generated underneath the surface is is becoming more porous and the methane and oxygen leak out and so maybe it's been there all along you know maybe maybe this is being generated abiotically you can generate methane if you've got the right minerals and the right heat along with water underneath underneath the surface of mars and we think all that is is indeed there and then you know methane can be generated in in these uh in this process and then it's trapped and then during the summer it just kind of leaks out all that's possible but so is life you know that we haven't we haven't excluded that as an explanation so what you're what you're witnessing is we have a series of fantastic measurements these are what we call um uh speculations about life and in in giving us if you look in total uh you know uh all all this speculation that that that all that is good positive information about the potential for life so what it what are they well water here on earth everywhere where there's water we've gone and we've looked there's life and we see water in various states on on mars mostly frozen but sometimes you know as we just talked about it could be liquid water check okay what about these life gases like methane and oxygen check okay circumstantial evidence that life may exist there what about habitable environments are there complex organic molecules there check okay there's carbon hydrogen oxygen nitrogen phosphorus and sulfur everything that make up uh life is we know it check all right it's in the soils the soils have nitrates in them okay here on earth nitrates are great for fertilizer and they're moist check check all right so all this you know all this circumstantial evidence is is is uh stacking up to make this a tremendously exciting planet in terms of its potential for past life and maybe some indication of current life now what what might this life be like does it seem that mars could really only support some sort of microbial life some you know some analog of a bacteria or something like that or do you think it could get a little bit more complex than that might we find algae you know or that oxygen might suggest photosynthesis of some type maybe what would we expect from martian life should we find it all right so uh we can't rule those out we can't say oh no way that's not you know we can't even think about these things and we do think about them because we can't rule them out and the rock so let's go back to the rock record you know bringing back the samples the pages of the geological history of mars great that's what we want we want to know how mars evolved but there's more much more let's take an earth analogy there are more than 4 700 minerals on this earth and 300 of them can only be made if life was there it's here on earth we make those minerals if we find those minerals on mars it game over we bring those samples back all right we're gonna we're gonna in our laboratory see that rock record go back in time and see if mars had minerals where life contributed lived died and contributed to that fossil record and then it tells us mars had past life and as i mentioned a little earlier it could have started out as plant life you know the the atmosphere was probably dominated by co2 even even in its past history so today you know if there's life on mars it's it's got to be under the ground it's not going to be on the surface we're pretty sure of that part the methane leaks through the surface you know the material we're finding was is conducive uh for past life in terms of of creating the these prebiotic molecules that we actually are finding with sam that's complexity and chemistry but if life exists it probably exists in these aquifers and maybe microbial it could be microbial life we don't know it could be that that because of the way mars is evolving and it's it's losing its atmosphere that the life in the in under the under the surface is in the process of dying off we may be maybe looking at a planet where it's evolutionary stage of its life is towards the end you know we are so lucky to have venus earth and mars in our solar system so that we could study and compare them because they're each at different phases and stages of their evolution okay you know so what's happened on venus could happen on earth what's happening on mars could happen on earth and so by by gathering this information and going after these big topics i think we can put together an under a better understanding as to the evolution of the life on this earth now it also has another implication if you think about it this star system had two probably three liquid water worlds and while two of them no longer are there was a time that they were so what does that say about exoplanets right so you're referring to the terrestrial planets okay uh but in reality there's there's also opportunities for life in the ocean worlds you know these are uh these are moons that orbit these giant planets so let's not forget them all right so i i believe that you know nasa's approach in the area of searching for life is a really important one we're looking for life in the solar system we're also looking for life beyond our solar system we're looking for similar earths you know we're looking for earth like planets well we have found earth-sized planets even some in or near what we would call the habitable zone but we can't tell if how much they are like us it could be all venuses for instance and we don't think venus has life on its surface at all you know it has huge pressure and temperature and uh and there's nothing we can think of that could have could we could even imagine living on the surface of venus at the moment but in its past it also was a blue world there's plenty of indication that early on in the solar system uh when the sun was young and and all and and and the planets had just been formed and and were evolving the venus earth and mars were all blue planets that's pretty spectacular and that's a relatively recent understanding and it would seem to suggest that blue planets are not rare in the universe yeah i agree let me tell you the solar system is a soggy place you you look out and you look at the amount of water in the giant planets and you look at the the amount of water in the outer part of our solar system at pluto in the kuiper belt you know we've got we've got an enormous amount of water in the solar system in reality it's just in different phases you know uh some of it liquid some of the gas some of it's solid uh some of it is is has been crushed to the point where it's it's it's stronger than granite you know i mean it's it's a real fundamental building block of our own planetary system in in our solar system and there's no reason to think that that it isn't pervasive at least in our arm or in our local neighborhood and maybe even further and we're seeing a lot of the a lot of the same stuff on in clouds of gas is very far away from earth so um i think water is a fundamental molecule that forms early on that that is absolutely essential for life as we know it and that makes us believe that these exoplanets could also have the potential for harboring life and one thing that's going to happen finally soon relatively soon is the addition of the james webb space telescope to our arsenal yes which will help us characterize some of these nearby exoplanets that's right that's right now we're finally going to launch when is the launch date for james wood okay so it was recently announced and it's october of next year october 2021 and first light i guess after testing the instruments will be some months after that right oh yeah several months four or five months i believe it's got to get into position i mean they have a lot of things to do they're going to be busy they're going to be real busy on that one you know it's all it's all folded up like you know the mysteries of origami and and it is all going to come out and it's got to deploy and then it's got to get into get into l2 which is uh behind the earth in a very special place and then it's going to be oriented such that you know the the sun shade constantly blocks the sun and then everything's got to get cold uh so that we can really use its capability to observe in the infrared which is very important it's a very important wavelength regime for us now back to life in the solar system we were mainly just talking about terrestrial planets now that's actually there's an even greater opportunity because of all of these ice shell moons where you have liquid water suspected underneath a shell of ice yeah and this this includes obviously europa and enceladus but also places like ganymede you know and i think oberon and you know all of these different places it seems like there's a chance for life and in all of the outer solar system planetary systems europa does seem to be the most exciting candidate though what are we going to do to try to determine whether there is a a biosphere under that ice at europa so one of the exciting things about europa is it's a moon about the size of our own moon it's sitting in orbit around jupiter at a place where the tidal forces from jupiter because it's in a slightly elliptical orbit when the moon is close to jupiter would you call that perijove you know jupiter squeezes it and then when it's a little further away called apogee in its orbit the the squeeze from jupiter isn't quite so much and so every couple days as as this moon orbits jupiter it's going through the squeeze and release and squeeze and release in fact the surface we believe the surface moves up and down as much as 30 meters every couple days you know in it once in its orbit it's doing this you know this is unbelievable when you think about it and and so that tidal force produces heat where's the heat going well it's it's heating the ice and melting it and it's creating the ocean and it's keeping the water warm it's doing it to the core of the planet and the core of the planet then is as it's being squeezed it has to be also interacting with uh the ocean in fact i believe i know what the inside of europa looks like all you have to do is look at io io is closer to jupiter than europa is and it has lost its eye shell the tidal forces have been so great that the ice is gone the water is gone and what we're looking at are volcanoes as jupiter squeezes that rock that body which is about the size of our moon over and over again every orbit and and and so consequently you're literally turning io inside out io you need a new google map of io every 80 years we we estimate a hundred volcanoes active all the time going on as you move further away from jupiter that tidal force becomes less and europa is just at the perfect place such that the tidal forces aren't so great to dissipate the ice shell in the ocean and it is maintained and it's been that way since it was created four and a half billion years ago now to me we don't talk about this much but for for life we don't know how it starts but there is one element of life in addition to the water and the right chemicals and in in in the right configurations is time i mean there's got to be time in the equation here on earth life just didn't spring up all at once it took a little time for whatever that life-giving process for whatever that that event that occurred that really started us off to happen and so time is an important part of the equation and europa has got it if there's anybody in the solar system that had that has all the right stuff and time to make life you know my bets on europa now i i think it's not going to be just microbial life it's had time to make more complex life okay and this is tremendously exciting and so where does that life live is a swim in the ocean and you know and and and so for us what we want to do is we go to the antarctic and we look at the antarctic ice shelves that stick out over the ocean and we get underneath them and we see that ice ocean interface and it's full of life life loves these interfaces we go to the bottom of our own ocean where there's hydrothermal vents you know where where there's plates that are moving and that also creates the energy necessary in the interior of the earth for for a material to pass through heat up bring up nutrients you know hydrothermal vents were only found originally in the ocean in 1978 okay i'm older than that all right and i was around when we first found the first hydrothermal vent in the ocean we now have been to about 300 of them there's probably tens of thousands of them down there and each and every one that we've been at is teeming with life whether the water that's coming out is alkaline or acidic they're still teeming with life that's that that environment is so similar i think to what may be happening at the bottom of the ocean on europa that i i can just imagine the more complex life that might be living there this is you know just a tremendous opportunity for us to interrogate that and our first mission called clipper is going to do just that now it can't get under the ice well one of the features that we have found out in the last 10 years that's really been exciting is that the ocean is indeed communicating with the surface it has to you look at the surface you look at where are the craters on europa you can only find a few craters on europa all the craters that have occurred all the impacts that have occurred on europa have been filled in that means the water has come up and it is filled in those those craters it's come up through the cracks europa is just full of cracks and in fact we have seen geysers now primarily from hubble you know we've made a number of observations where we do see these walls of water coming out but also we've gone back into galileo data and realized that we flow through flew through two plumes of water uh at uh at europa and in you know i've talked to many of the scientists and they remember the data they didn't understand the data to the point where they couldn't publish anything because they couldn't make any sense out of it now we can make sense out of it so we expect the life to come to us so clipper is going to is actually an orbiter of jupiter and europa so as it as it orbits jupiter it's going to come out of the radiation of jovian radiation belts it's going to it's going to with its cameras look at europa looking for plumes and then as it swings around it's going to fly back into the radiation belts fly by europa and and we're going to want to target the the plumes we're going to want to through the plumes and it's got some tremendously important instruments on it to be able to make some great measurements so we're hoping the life will come to us and then if that is the case and we get some positive indications then we're going to want to get down to the surface and get into the cracks and get into the ice water interfaces because that will be teeming with life if it's like anything that we see here on earth now if it is and this brings up the idea of convergent evolution if it is complex or there is complexity there you might just you might see some really interesting things below that shell of ice like bioluminescence and things that we see deep deep in our oceans sure and you might see the same things i think it's going to be even better than that and here's why if we turned off the sun jupiter would still glow in the infrared okay jupiter is 300 earth masses you know it's an enormous body and it radiates in the infrared it's it's it's like it's still cooling off from when it was made all right just like you put a cake in the oven you take it out and you sit there and and you wait because it's still cool it's still cooking it you know it's cooling off that's exactly what's happening to jupiter generates an enormous amount of infrared and so just think about it that infrared light is bathing those galilean moons and the cracks are such and maybe the ice in certain areas are thin such that even though the moon is tidally locked that means that one side of the moon in its ocean and the ocean we believe is everywhere around the core it may be lit by ultra infrared light coming from jupiter where the intensity might increase in these areas where where it comes through the cracks so so that's that's light that may affect the evolution of complex life that could be in the ocean now i have to say that it's one speculation after another but that may be true and we're going to find out if complex life were found in a nice showed moon like europa or maybe maybe even several of them maybe even distant kuiper belt objects or something if they've got a radioactive decay heating the uh in the core yeah and there's we believe there's water underneath the surface of pluto yeah in in in a shell right yeah yeah and this makes the idea of a habitable zone sort of moot because your entire star system is essentially a habitable zone at that stage for ice shell moons and planets now if complex life were common in the solar system that would suggest it's probably probably common everywhere in which case yeah i would i'd even forget the suggestion it's got to be everywhere it's got to be everywhere yeah man it's everywhere well even if even if we just find a microbe that is not that is clearly not related to earth life it did not get there through panspermia or anything else it's native to mars or europa whatever that answer is essentially the question that life on earth is definitely not alone in that the universe probably teems with microbial life at least find complexity and you can start to play with ideas of intelligent life that's right being more common than one might initially think and this brings us to techno signatures correct now nasa sort of shied away from seti for many years for political reasons and things like that but now it's a different story it's a different question correct now it's about any sort of techno signature and nasa's getting back in the game what's going on there so when we started to find exoplanets the concept of techno signatures is really important and it's changed significantly well beyond just listening for radio waves and the reason for that is the fact that we're observing these planets around stars in various phases when you think about what we see we see the transiting planet and that gives you an indication that that's that there's a solar system there but we're developing a variety of instruments in capability in the future to be able to isolate that planet and look at it so the planet as it goes around that sun when it's when it's on the other side of the sun and comes out its hemisphere will be lit and we'll look at its spectrum and we'll see what its composition is we'll look at trace gases perhaps there are pollutants in the atmosphere pollutants because of intelligent life if we get good enough we might be able to tell as the planet spins and everything seems to spin in our solar system there's no reason why planets out there don't spin too that perhaps we can see variations in the light that is being reflected or absorbed by the planet that indicates land ocean clouds changing albedo that could make it much more interesting much like an earth we also can look at the planet when it starts the process of going in the transit phase so it now is between us and the sun and now we want to look at the night side of the planet is there excess heat waste heat from energy sources are there some aspects of illumination perhaps faint spectrums of light the concepts now in terms of detecting these kind of techno signatures are have exploded and that's why nasa's gotten much more involved in this and it's due in fact to the increased knowledge that planets are everywhere there are more planets than there are suns and we have plenty to do to interrogate these planets and we're moving in that direction all right jim thanks for appearing with us today and i look forward to watching all of these missions and we didn't even touch on some of them like the titan copter which is about the most amazing mission of all of them it is it is we should talk about weird life one time now that could be really interesting because that would be low temperature life and now that's really alien indeed i mean you know water's such an important element of our life as we know it but you know you need a liquid that's part of the metabolism system on titan it's not liquid water it's liquid methane you know and so it might be life like we don't know it titan would be the place to go to answer that question absolutely amazing and soon we'll have a helicopter there that's right just like just like we have on we'll have on mars indeed one last thing you are also a podcaster i am and have had a podcast for several years now tell us about that well the podcast is called gravity assist and to me it's really all about an intimate discussion with a scientist friend of mine i want to invite everybody to our starbucks table as we're sitting there talking back and forth about our science and what we're doing and i'm trying to understand what they're doing and so this is my fourth year and then this season is all about the search for life now the name gravity assist comes from the fact that every one of the scientists i interview i asked them what was the person place or thing that occurred to them that got them so excited accelerated them to a new object a new direction like a gravity assist does for spacecraft that that then use that technique to go to a different planet and they all know it you know gravity assistance it happens to every one of our scientists because you're not born thinking you're going to be a scientist i certainly wasn't i haven't ran into anybody yet that does that now where can people find this podcast so it's on www.nasa.gov podcast nasa has a number of them you can go down the page and gravity assist is one of them all right jim we are out of time i appreciate you uh appearing with us today and i look forward to what looks to me like another golden age of the search for life indeed well thank you so very much i enjoyed it is this a new golden age of exploration recent events in both private and public space initiatives seem to bear that out with no end in sight exciting times [Music] indeed [Music] you

Channel: Event Horizon

Views: 434,100

Rating: 4.7635021 out of 5

Keywords: europa, life on europa, europa ocean, Dr. James Green, NASA Chief Scientist, Jim Green, Mars, Mars 2020, NASA, Life in the solar system, alien life, alien, water on europa, water on mars, life on mars, perseverance mars rover, europa clipper, titan quadcopter, complex alien life, fermi paradox, Is life on Europa?, Why the Solar System May Be Full of Life, john michael godier, asmr, godier, event horizon, event horizon john michael godier, titan, jupiter (planet), extraterrestrial

Id: RQqQjmIP7VU

Length: 70min 41sec (4241 seconds)

Published: Thu Aug 13 2020

Reddit Comments

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Because I Do

[u/ericlikescoffee]

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[u/ericlikescoffee]

If God came to you and said I Will make one planet of your Choosing capable of supporting life like the earth what planet would you choose? I Would Choose Venus