 Hi everybody we're about to get started with trivia in just a moment here but since I see some people trickling in still I want to make sure that everybody who wants to join us for trivia has a trivia sheet and a pencil or a pen. If you still need one go ahead and come up to the front here or just raise your hand but it it looks like you're coming up to the front so that's even easier thank you okay so that was the first round through the trivia questions now I'm going to go back and go through them all again but this time only give you about 15 seconds per slide so you can like check your answers get any questions you missed etc all right um that's it for trivia so if you um if you missed anything let us know right now we'd be happy to run back to to a slide real quick if anybody has any they need to check again but otherwise go ahead and bring your trivia sheet and your little golf pencils up to Sam over here and um we're going to get those graded during the first talk and in the intermission between talks we will announce the winners and then the winners will after the second talk be um they'll they'll come up here and collect prizes because we have prizes okay so now it is my pleasure to introduce our first speaker it's going to be Lucas Piper he is a PhD student and the University of Washington's Earth and Space Science department he works with Dr. David Catelyn and he's going to be talking to you guys today about using icy eruptions to look for life and Enceladus is unseen ocean so now I'm going to invite Lucas up give us a stop can you hear me okay in the back it's okay louder a little louder is this any better okay good that's him that's him good okay awesome um I'll try not to turn away from the mic um so hello um my name is Lucas Piper and like I said um and today I want to tell you this little story about icy eruptions on Enceladus what they can tell us about life uh in an ocean under the surface on Enceladus so before we journey out for the outer solar system Enceladus resides um let's take a moment here on earth and I'd like you all to imagine um if you went down to the coast and stood in the shallows of the Pacific Ocean and you brought a bucket with you and you used that bucket to scoop up some water from the ocean now how much life do you think would be in your bucket so maybe you get lucky and you find a small fish swimming around at the bottom of your bucket maybe you find a lucid of seaweed that a wave carries into your bucket but what about all the life you don't see so in an average bucket of ocean water there are over 10 billion bacteria and over 100 billion viruses so even when we don't see it the oceans of our planet are teeming with life so what about on other world put the oceans on other planets do moons in our solar system be a good place to look for life too let's try and answer this question so uh our nearest neighbor is the moon this is a real picture of the moon by the way it's taken from the international state station uh and our moon purchased on one moon it's rocky and dry unlike we have any any light there beyond what humans think but we can look a little further out in our solar system to the planets we call the gas humans jupiter and Saturn and these giant planets have many moons about 60 each and many of these moons have liquid water not on their surfaces but underneath their surface so here is a 3d model of one of these moons of Europa this moon of jupiter and you can see earth down here for a size and Europa has this thick outer layer of ice and underneath that ice is a deep ocean of liquid water and it's kind of hard to see just how deep it is from this picture but the ocean of Europa is about 10 times deeper than even the deepest parts of Earth's oceans so uh unfortunately with Europa and moons like it it's really difficult to see what's going on inside so these these outer layers of ice prevent us from observing the ocean directly um someone else down the cat uh so uh it's really difficult to see inside of these oceans we can't like use telescopes from Earth to observe the ocean directly um even if you landed a spacecraft on that surface you'd still face the problem of drilling through miles of ice just to get down to the ocean but there's one moon in our solar system where this outer layer of ice isn't a problem so Enceladus is a small moon of Saturn you can see just how small it is here comparison to Earth the distance from its north pole to its south pole is about the same as the distance from San Francisco to LA um and for a while there wasn't much that we knew about Enceladus other than the fact that it had this unusually bright and white surface and no one was really sure why that was the case that is until the Cassini mission so the Cassini mission was a joint uh mission between NASA and the European Space Agency where they sent this spacecraft with no people on board out to Saturn to investigate the range planet and its many moons um I'm going to show you a few pictures from the Cassini mission there are so many more so next time you're like bored at your computer please google like just NASA Cassini images you'll find so many um this is sort of the north side of Saturn you can see it being lit up by the sun it's casting a shadow on some of Saturn's rings in the background uh and at the north pole of Saturn it's an enormous hexagon shaped storm that's several several times the size for it it's a pretty well thing um here is another Cassini image this close up of some of Saturn's rings and one of Saturn's smallest moons called Dackness over there on the right it's only about five miles across um and its orbit is within some of Saturn's rings which you can kind of see here but yeah it's it's not showing up great but there's like rings above where the moon part as well um and because Dackness's orbit is within this kind of ring structure that goes along in its orbit it creates these interesting wave-like disturbances in the ring particles here's one more Cassini image you can see Saturn in the background and you can hopefully make out in the foreground this is Saturn's largest moon called Titan Titan is the only moon of Saturn that's large enough to hold on to an atmosphere so you can see it's kind of hazy atmosphere right here um Titans are really interesting moon in terms of looking for light because not only does it have an ocean underneath its surface just like Europa um it's also got this atmosphere and it's got liquid on its surface not liquid water but lakes and seas of methane and ethane so it's a really cool uh place to think about life that could be very different from life um but so Titan deserves its own talk but I want to focus on Enceladus for tonight so when Cassini turned its attention to Enceladus it found something really surprising which was huge eruptions coming out from cracks in the in the surface of Enceladus near the south and these were shooting out hundreds of miles into space and uh so what was only at first a small part of Cassini's planned mission it became a top priority to get a closer look at these eruptions this is another actual picture from the Cassini mission um this is the surface of Enceladus and you can actually kind of make out the cracks where these eruptions are coming out and Cassini didn't just take pictures of these eruptions it actually flew through them and measured the different chemicals there and what Cassini found is that these eruptions are mostly made up of gas such as water vapor so you can kind of think of these eruptions as like huge jets of fold steam and being carried along in this gas there were also little particles of ice and these ice particles contain salts and some organic molecules and organic molecules that doesn't necessarily mean they don't always have to come from life they just have carbon in them but organic molecules are like the building blocks all life on earth so definitely exciting to find here these icy particles are also interesting in that they're what help us see these eruptions in the first place in this image you can see them glinting in the light of the sun and they're also what's responsible for Enceladus's bright white surface because while some fraction of these eruptions escape from Enceladus's gravitational pull and actually some of that material is what supplies the e-ring if you got that trivia question right some fraction of the eruptions kind of snow back down onto the surface and give Enceladus its nice fresh white coating of ice so here's one more image of Enceladus from Cassini but you can maybe make out another of Saturn's moons in the bottom right over there that's Pandora and then some of Saturn's rings in the background here and again we see these strange eruptions of ice and gas coming from the south full of Enceladus and at first it wasn't really clear where exactly these eruptions were coming from so some people thought that maybe this was gas being released through cracks in the surface and that the little ice particles were getting kind of swept up in that gas kind of like sand whipping through the air on a windy day at the beach but then when it became clear that there was salt in them well that was kind of surprising because salt and ice don't play well together um if you had say a cup of salt water and you froze it you got it cold enough to freeze the salt would tend to stay behind in the liquid water and the ice that forms would tend to be pure ice so salt mixed in with the ice here had to mean that this these ice particles weren't coming from a pure ice surface they had to be coming from a liquid water ocean that had salt somewhere below the surface and at first it seemed like maybe this ocean was only near the south full where these eruptions were happening but then some scientists noticed that Enceladus wobble was a little bit as it moves in its orbit around Saturn and so this means that basically its outer icy shell and its rocky pores seem to move separately from each other um if the ocean looked like this if it was only near the south pole then you wouldn't expect that behavior because the core and the ice shell would be more or less connected everywhere or almost everywhere so you would expect them to move rigidly so the fact that you observe this wobbling has to mean that the ocean under the surface is everywhere under the surface and it's sort of separating the core from the ice shell all the way around so now we see why Enceladus is unique it's the only moon in our solar system in the only world apart from earth where we can get a taste of an ocean from the surface we can't get a bucket full of the ocean water directly but we can get a bucket full of these eruptions and we can begin to ask could life exist inside this ocean and by extension could life exist inside other icy moons where we aren't lucky enough to have these eruptions and while we haven't found any direct evidence for life yet we do have a pretty good idea now of what kinds of life could survive there so there is no oxygen measured in the eruptions and since fish need oxygen to survive you're probably not going to find any Enceladian sea bass and because the ocean is underneath miles of ice there's no sunlight down there it's pitch black which is pretty creepy to think about so plants like seaweed which needs sunlight to survive they're out of the question too but bacteria and microbes some of them can get by just fine without oxygen or something so could they exist in Enceladus's ocean well maybe so there's one type of microbe in particular and this exists on earth we see them especially around hydrothermal environments which are these warm areas of the sea floor that are heated up by magma beneath the sea floor and these microbes use a couple of gases so they use hydrogen which is a gas we used to use in airships with mixed success and carbon dioxide which is a gas that we breathe out and they use these two gases together to make methane which is a common natural gas now all three of these gases were measured in the eruptions which is pretty cool I think this begs the question is there enough in the ocean for microbes to actually use well at this point it's important to remember that what we're seeing is not the ocean itself we're seeing the aftermath of some complicated eruption process and we're trying to make guesses from that eruption about what it was like at the beginning in this ocean so I think looking at the eruptions and to make guesses about what's going on in the ocean is a little bit like looking at a cake and trying to figure out the ingredients and in this case you're not allowed to ask for the recipe because it's buried underneath miles of ice so what a cake looks like and tastes like depends not just on the initial ingredients but also the conditions under which it was baked like how long it was in the oven and the temperature of the oven was set to in the same way what we see in the eruptions the chemicals we find there are a product of not just what you started out with in the ocean but also the processes that brought them up to the surface and may have changed them along the way so that's what I focus on in my research it's trying to understand the steps on this journey from ocean to eruption and uh yeah I forget what I was going to say oh yeah and how this icy gassy stuff gets changed along the way so let's take a closer look at the journey of that eruption through a crack in the outer ice lake that's where we're headed okay so this is a diagram a drawing of a close-up of these ice cracks you can see the eruption coming through that crack originating from the ocean that's sort of underneath the ice and partially filling the cracks so one of the first questions you might ask at this point is why is this eruption happening in the first place well Enceladus is such a small moon it really has uh gravity is very weak there so Enceladus has a lot of trouble holding on to any sort of atmosphere this means that the surface and water that fills the cracks in the surface is basically being exposed to the emptiness of space sometimes we call that the vacuum of space and that's really an appropriate term here because it acts like a vacuum cleaner and sucks out water and whatever else is in the ocean it creates these eruptions as water is sucked out of the ocean it gets turned into water vapor and other gases that that are in the ocean they can bubble out as well kind of like a soda going flat or a beer losing its solids but water vapor will come or water will come out of the ocean faster than other gases come out and even between the other gases there can be differences like between carbon dioxide and hydrogen and so generally gases that come out faster you'll tend to see more of them in the eruption they'll be kind of over represented that's not the end of the story because as the eruption continues upwards it gets colder and colder so cold that some water vapor freezes on to the walls of these ice cracks it's the same process by which you sometimes get ice building up in your freezer and the walls get so cold that they pull moisture out of the air and ice builds up it doesn't get cold enough for other gases to freeze out like that so water vapor is the only one that's effective so how do we know that all this is happening there's no real easy way to see this happening even in the Cassini images but yeah especially what's going down going on down at the bottom of these fissures these are it would be miles down from the surface to this water and yeah basically it's hard to see down oh yeah these these cracks are very narrow so there there may be only like a couple feet wide maybe even narrower so it's like trying to see down this very narrow ravine all hope isn't lost though because well these we can't directly see these eruptions beginning to form we can recreate a little piece of that process in the lab so that's what i try and do with this experiment which is one part of my work down here is a stainless steel cup it's for context it's about the side of the can of beans and inside I put water that represents soliduses ocean and then that pipe going over to the right will lead to a vacuum so I can remove gas from this cup and make it so that the area above the water is empty just like outer space um that handle up there just lets me open and close that pipe to the vacuum or I could switch out the vacuum for a tank of gas and I could introduce some gas into the system that I want to make uh finally the device up at the top just measures the pressure in this cup so it tells me the amount of gas in the space above the water and that is connected over to a computer so I can keep track of how that amount of gas changes over time during an experiment and I'll take you through what it's like to do one of these experiments so here's a close up of that cup of water um so at the beginning the first thing we need to do is turn on the vacuum to get rid of any gases that are already in there because there'll be some gases inside from our own atmosphere and oxygen and nitrogen which are common gases in our atmosphere they weren't measured in the eruptions so we don't want them in our experiment so we use the vacuum first to get rid of those gases and then we add in a gas that we did see in the eruption so maybe methane we add this methane to the cup and uh and at first it's sort of floating around above the water but if you give it enough time gas will dissolve into water just like you can dissolve sugar or salt in water and over time it'll begin to dissolve and eventually create this kind of balance between the gas above the water and the gas in the water uh so now our homemade enceladus ocean is ready it's got gas in it that we've seen in the eruptions and we just want to measure how fast it would come back up so we use our vacuum once again to remove the gas from above the water and now we've created our own miniature version of the vacuum of space up here and now we quickly turn off the vacuum and gases will come out into that empty space and try and create a balance once again and as that happens we will use our trusty device for measuring the amount of gas above the water and we can see how it increases over time and just by looking at the curve of the the graph that we get out we're watching how fast gases are coming out of this water so with just a cup of water and a vacuum and a vacuum we're able to measure how fast these gases would come out of an ocean on an icy moon that's almost a billion miles so that's one part of the story what about the second part you mentioned earlier where water freezes out onto the ice uh the cracks of the ice shown how do we know that this is happening again there's no real easy way to see this happening but there's one reason we know it should happen and that's based on the temperature of these icy walls so Cassini was able to measure the temperature of the surface of enceladus and near these cracks the temperature is right around minus a hundred degrees Fahrenheit which is about the same as the coldest temperature ever reported on earth somewhere in Antarctica this is actually one of the warmer spots in the surface further away from these cracks the temperature goes down to like minus 300 degrees Fahrenheit so kind of unthinkably cold um we can't directly measure the temperature down at the bottom of this crack but we can use what we know about the freezing point of water to figure out that temperature so water freezes at a temperature of 32 degrees Fahrenheit so if you put ice in contact with water whether that's ice cubes in a glass of water or an iceberg in the ocean the temperature of both the ice and the water shift to right around 32 degrees so from that we know that where this ocean is in contact with the ice walls the temperature should be right around 32 degrees so I mentioned earlier that because these walls get colder towards the surface the uh some of the water vapor freezes out onto the walls building up like on the walls or pleats and this happens all the way up along the eruption stream but we want to try and figure out exactly how much water gets lost to the walls during that process so to do that we use equations that represent the freezing process and equations that represent the plumes for this eruption and its upward motion and we try and calculate exactly how much water goes missing so what we're really trying to answer here is um how difficult is the journey for water vapor and that depends on two things that depends on first how deep this crack is and second how wide it is across so if you have a very deep or narrow crack in this ice shell then water vapor has a very long and difficult journey there are plenty of opportunities for it to run into the ice walls and freeze onto them uh but on on the other hand if you have a very wide or shallow crack then uh then the water vapor it's just like a short trip down an empty tanling highway lots of water vapor can survive that journey to the surface the trouble is we don't really have a good handle on the size and shape of these cracks in the ice shell they could be a mile deep or five miles maybe 10 miles down to the water they could be very narrow across like only an inch or maybe a foot or the largest we expect from images of the surface is that they could be about 10 feet across so to try and take into account all these possibilities we run our models for a bunch of different widths and a bunch of different deaths and one of the ways that we can check to see that the particular model is realistic is we can see how much of an eruption it would produce and we can compare that to what Cassini saw in those images so compared to a narrow crack a wider crack might create too much of an eruption more than what we saw in the images so we can rule out that model or if you had a very deep crack maybe so much water vapor goes lost along the way that you're only left with this little wisp of an eruption that's left that we saw in the images we could rule out that one wisp so with all that we now have a pretty solid understanding of what it takes to go from an ocean to an eruption we've used a homemade ocean in a cup and some knowledge about the physics of ice and water and water vapor so now we know which gases come out fast which come out slow and how much water goes missing along the way so we can taste our final product the eruptions and make some pretty good guesses about the ingredients that we started out with in the ocean and importantly how much of these ingredients there are so from this work what we found is that there should be quite a lot of hydrogen and carbon dioxide and other gases in the ocean so much so that this ocean is probably about as bubbly as a soda and that's not at all an exaggeration so there's plenty of gas for microbes in the ocean to potentially use you could also say it's about as bubbly as a beer which brings me to a very exciting announcement I'd like to make this is very much not a real thing but we're we're collaborating with vicarious spruehouse to develop a beer that has all the tastes and chemical qualities of the cellarist ocean so you can look forward to a beer that is undrinkably salty it's not as bad as earth's oceans but if you can imagine like one part ocean water to two parts fresh water still pretty gross if the salt doesn't kill you then don't worry because the ammonia definitely will we think there should be a lot in the in and solidest ocean so we're adding it to our beer it also give it a nice aftertaste of window cleaner um and then lastly instead of doing the traditional carbon dioxide bubbles uh or or nitrogen bubbles like in a nitro stove we're opting for the full suite of gases that are in and solid as this ocean so that includes hydrogen and methane um so I should warn you not to open these near an open flame um or you'll have a miniature recreation of the hindenburg on your hands um but in all seriousness while this sounds terrible to drink and probably legally poison these a lot of these qualities are not necessarily bad or other types of play and in some cases are actually beneficial I mean you wouldn't want to go and drink ocean water on earth uh either um so salt is no problem for aquatic life on earth ammonia well that can be toxic at some levels ammonia is also a really important source of nitrogen uh which is a key nutrient for all life on earth and hydrogen you already know hydrogen is a source of energy for this type of life that could be on enceladus and they produce that type of life produces methane which is also measured in the eruptions so all in all enceladus is a really good place to to find life because there is energy for life in the form of this all you can eat gas buffet there are the building blocks of life in those organic molecules I talked about earlier in the ic particles uh in addition to those organic molecules or in some cases within those organic molecules we've actually detected all six of the the most essential elements for earth life they were all detected in the eruptions of enceladus carbon hydrogen oxygen phosphorus and solar were all detected not only is enceladus a good place for life to exist it's also a great place to go looking for life because these eruptions are bringing samples of the ocean from that ocean up to the surface and beyond where we can oops where we can actually measure them um so that brings me to my next slide um excitingly uh recently this this mission called the enceladus orbitlander was prioritized for it's going to it's the number two priority for the next big nasa flagship mission um so that's a lot of words but basically it's really good news for uh for a return to enceladus um and following up on where the kasini mission left off and uh this this mission is called the enceladus orbitlander because it would have two phases to its mission the first phase is an orbital phase where it would do something kind of similar to what kasini did where it would fly around enceladus and fly through those eruptions again but this time with bigger and better instruments to make uh you know help us find out even more about what's going on with those eruptions and then it would have the second phase where it would land somewhere on the surface somewhere near the cracks where those eruptions are coming out and this this lander could surround around for things that have already fallen out of the eruptions where maybe even catch particles as they snow back down to the surface um with this improved suite of instruments compared to what kasini have the orbitlander would not only have a better chance of detecting molecules that may be produced by life it could also look for life itself like microscopic life that could be preserved in those little ice particles frozen in in place in those little droplets of what it was once enceladion seesper so what do you think if you traveled 800 million miles out to enceladus and you brought a bucket with you and you used that bucket to scoop up some of the eruption from that strange salty soda lake ocean how much life do you think would be in your book thank you thank you all right thank you lucas and okay we have time for just a few questions here we'll probably do two or three of them depending on on how fast that goes um so if you have a question for lucas go ahead and raise your hand and i'll let lucas step back up to the mic and answer any questions okay no yeah that's good yeah so so everyone can hear the question the question was what causes the ice to crack in the first place and do they eventually seal up could they form somewhere else we don't know exactly why the cracks start in the first place but what we do know is that the the ice shell of enceladus is thinnest at its uh its north pole and its south pole so that explains why these eruptions are at least happening at the poles but then why is it only happening at the south pole that's still an open question people think maybe there was some event in the past some kind of thermal event under the surface that started these up and i think there's been some modeling work to suggest that once you kind of get these started in one place at one pole it's really hard to get them started at the other pole because it's just kind of there's more flexibility in the whole ice shell i guess yeah but they could definitely be sealing and reforming over time i think there's also evidence that like the the cracks used to be there used to be cracks of like different orientations just in terms of like their angles but still all at the south pole yeah um let's go hand over here yeah oh that's a good question how old is the ocean we don't know um so we don't even really know how old the whole moon is so uh it could be like age of the solar system so that's four and a half billion years so that would be like similar age to earth it could be way younger some people think it could be like only a hundred million years um old but we really don't know right now um yeah good question yeah actually where does the energy come from to form what oh oh yeah um so yeah i guess i mean you can think of uh because this water is kind of just being exposed to the vacuum of space it is just getting kind of pulled out from there there's also been some suggestions that maybe this energy uh has to do this kind of comes originally from tidal forces um because basically the force of gravity from Saturn is quite strong it's kind of twisting and stretching and squishing and solitis um this is probably why this ocean exists in the first place there's as you squish and stretch the core inside and solitis it's creating heat and melting ice and and allowing for this ocean to exist so maybe that tidal energy is connected as well but could just be kind of opening up the ocean to the vacuum of space and letting it go yeah yeah so why was there a question mark next to sulfur why was that the only one of the six elements that had a question mark um yeah so uh i mean we we really Cassini wasn't i mean remember Cassini went up without even knowing these eruptions existed it was pretty well equipped for i mean it did an amazing job for for what it could do but yeah we only really have confirmation of like four gases apart from water vapor that are that are there um so that's carbon dioxide hydrogen ammonia and methane um but hydrogen sulfide which would be something that contains sulfur that's like a an ambiguous like maybe it's there we're not really sure um but with something like the orbital and or maybe we could get a confirmation all right let's do one last question it's this sounds kind of weird doesn't it all right well let's do one last question and then we'll then we'll move on with uh trivia yeah that's a great question so yeah uh could there be other more interesting gases that don't even make it out of the ocean i think uh they probably would make it out of the out of the ocean because most gases like are pretty volatile they don't really like staying in this dissolved state if they're open up to the ocean they should get out um i think i maybe it could still be really difficult to see some of those though if they're only present like really like small abundances yeah so yet another reason why we need another mission to go back with better resolution all right thank you all for your questions thanks give me another round of applause yes great talk to you i'm gonna switch over to this mic that sounds a lot better to me um all right so we have some trivia well we have a trivia winner um and then we have like a lot of people who got six out of ten right um and these may not get degrees but they do actually get trivia prizes so i'm gonna announce first all of the all of the 60 percenters um and then i'm gonna announce the big winner and then if you win at trivia um sit tight because after the second talk we are going to let you come up and choose your prizes um and we're we're gonna let we're gonna let the eight-point winner the 80 percenter uh choose their price first because that's their that's their right as the actual winner and then i'll use 60 percenters to come up and pick from what's left um so uh starting out here with six out of ten correct we have nc let us and and c is at the a like like the avalanche like the ocean or something or like the airport all right great job yeah and i do i do want people to like raise their hands or like shout out or something when they win so that we know who it is and we can all applaud them and be very impressed um all right the the next trivia winner is uh their team name is team name so with you know they get no applause for uh creativity but oh okay what okay they actually got different ones correct so we will let them choose their own prizes i was going to say that's only one prize if you got like the exact same one fight but yeah um all right we've got um s sbp curly hairs nice okay i get it now uh sky pie all right great job up front here and um joe boat that's well done and the last um 60% winner is uh thea and mark great great job all of you i know six out of ten doesn't sound great but it was in the context of this trivia which was apparently pretty hard so pat yourselves on the back um and then the big winner drum roll oh okay stop you're scaring the cat okay the big winner is dan well done dan all right so so just sit tight and we're gonna have you come up and collect your trivia prizes after sorry dance um after the the last talk just so we're not crowding up here right now right now we're gonna have about a uh five minute intermission um and then we're gonna introduce our final speaker of the night so go ahead and get another beer it'll maybe it'll be a 10 minute intermission so you have time to get mine and get another beer and all that stuff get some food if you need and we'll be back in just a few minutes thank you all right hi everybody i know i know you're probably not all back from getting beer yet but those of you who can hear me are um i messed up i forgot to go through the trivia answers so you know who win who won but you don't know why it's not you um so i'm just gonna run through those real quick so that it's not a mystery uh so question one which early 20th century astronomer promoted the idea that marz's surface had canals on it that is Percival lull um this this is like a little preview of next month when we're going to have a bunch of astronomers from lull observatory here so you can look forward to that um yeah hey Percival lull how long ago was marz thought to have liquid water on its surface the answer is approximately four billion years and andrew what's your precise answer about three three to four billion years but i it clearly rounds to four so viking one found proof of civilization on marz um which of the following martian rock formations has been claimed to be proof of the work of an intelligent civilization that is obviously the star fleet logo oh oh there's a knot in there so it's not the star fleet everything else has i'm going to make the claim right now though that it's the star fleet logo so this question is now incorrect the highest surface temperature in the martian summer is equivalent to the average high temperature in seattle during which month and the answer is june 71 degrees fahrenheit Saturn's icy moon in celadus is only one seventh the diameter of our moon or about how many miles so if you do that math real quickly it's obviously 300 miles the casini mission's observations of enceladus and its geyser like plumes provided evidence of cryo volcanoes a subsurface ocean and hydrothermal vents which you just learned i guess did you i don't know if we exactly touched upon this question but uh true or false enceladus is plume supply the material for Saturn's outermost ring you did just learn this one the answer is true number nine scientists have used Antarctica as an analog to study which phenomenon in enceladus and the answer again is all of the above because whenever all of the above is an option that's obviously the answer and the final question a proposed mission to enceladus the orbalander would include how many different instruments to robustly detect possible signs of life this is kind of just a like guess a random number question uh so if you got this one right congrats the answer is six if you actually knew that somehow then that's excellent you probably work for jpl or something um okay great so now now you know why you won or why you lost or or whatever and so i am going to hand the mic back over to megan who is going to introduce our final speaker of the night in just a moment here which of us and i have one oh you have one okay okay so it is my pleasure to introduce our final speaker andrew shumway uh he also works with david cattling at university of washington's earth and space science department and andrew and lucas of course are both a part of the university of washington's astrobiology program um and so with that i'd like to invite andrew up here if he's done fiddling with the mic all right we're good to go so everybody welcome andrew shumway thanks for that introduction so i want to pretend for a moment that i am a billionaire ceo of a space travel company and to thank you all for coming to my talk i am offering each of you a ticket to visit mars on a spaceship that i built that can safely transport humans from earth to mars for the very first time so just by a show of hands how many people would like to join me for a few weeks vacation on the red planet no it's it's just a vacation you come back um okay so maybe not everyone's convinced and for good reason mars is not an extremely hospitable place um and to explain some of the challenges that humans would face on mars let's go down to the surface welcome to the surface of mars where for most of the year the temperatures are colder than an arctic um there is no oxygen for you to breathe and in fact there's very little air at all and because there's no oxygen there's no ozone layer to shield us from the harmful uv radiation from the sun meaning a few minutes outside without a space suit on you would get a severe sunburn and longer exposure could lead to more severe consequences but there are some workarounds to get around some of these hazards for example we can build structures or wear a spacesuit to protect us from the sun's uv rays to keep us warm and to provide us with oxygen to breathe but there's still one challenge that we just haven't figured out and that's one of the most important ingredients for life we just heard a lot about it from lucas's talk where is the water where are we going to get water on mars so i hate to break it to you i'm not actually a billionaire i'm a grad student um so i don't have a ticket for everyone to go to mars or rocket ship so why am i asking these questions the reason is one day humans will go to mars and when they get there they're going to need water to survive to drink to water crops to take showers and stuff like that and water is extremely difficult to transport because it's so heavy and it just costs a lot of fuel to move it from one planet to another so it would be great if when we get to mars we can find a source of water that's already there and use that and it could be your children or your grandchildren who are the first humans to set foot on the red planet but even more importantly if there is water on mars and we can find it humans are not the only creatures that need water we just heard from lucas about the these microbes that can maybe survive in small pockets of water on mars and so if we find the water we might be able to find life so that leads us to our second goal which is finding life on mars so this is a really big challenge so really big goal here i'm trying to break this up into four easy sections to tackle these goals and i did that in the style of my favorite tv show from childhood i see some fans are out there this is avatar the last airbender if you're not familiar with the show the premise is that the hero has to learn how to control all four different elements and save the world and i realized as i was thinking about my research that actually these four ingredients are extremely important for the search for life so i've broken up the talk into these four sections and we'll start off talking about the air on mars so what we're looking at here is the surface of mars the horizon is the bottom part of this image and the light orange and then we have a thick orange haze which is the entire atmosphere of mars which separates the surface from the vacuum of space but just like earth mars has an atmosphere but that's about where the similarities stop like i mentioned before the air is extremely thin so imagine as you climb a mountain the air gets thinner and thinner um even the top of mount everus the air is 50 times thicker than the average air on mars so very little air to go around and none of it is oxygen so we're just out of luck we can't we won't be able to breathe there instead the atmosphere is mostly made up of carbon dioxide which is good for some organisms like plants for CO2 but we do not there's also a small amount of water vapor in the atmosphere you can think of this like the humidity if it's more humid there's more water in the air and also a lot of dust gets picked up and in fact mars will have sometimes global dust storms where a dust storm envelops the whole planet and it lasts for days or even weeks so already just from looking at the atmosphere we can see there's a lot of interconnection between the different elements there's water in the air and there's dirt in the air which brings us to our next section earth or i guess we maybe shouldn't call it earth because it's mars um so maybe i'll just call it dirt or soil or because i have a chronic case of science brain i might slip up and say regolith but it's all the same thing well i want to introduce this by with starting with a game um i want you to guess in just a minute whether the pictures i'm about to show you are earth or mars what i'm showing just to get us oriented is a satellite photo of either earth or mars showing a landscape that was carved by water we can see a bunch of different tributaries all flowing together into one big river so show of hands who thinks that this is a picture of earth okay and raise your hand if you think this is a picture of mars if you said earth you were correct this is another place on earth what bunch of water flowing in together don't worry there's another chance right here so again i'm showing the exact same feature we have a bunch of water flowing together a bunch of rivers tributing into a giant river so show of hands who thinks that this is earth all right who thinks that this is mars all right the low res photo is maybe a giveaway and the craters that's a that's also that good way maybe i shouldn't say that to the games but so we can see that there are two very similar features on earth and on mars we know that this feature on the left is carved by rivers on earth and on right we it's the exact same features so there was clearly water once on mars but not anymore okay let's play another round here i'm showing one of these photos is earth one of these photos is mars um this time instead of a river we're looking at a delta structure where a river has flown into a standing body of water like a lake for an ocean and when it does it deposits all the sediment from upstream and creates a fan like structure kind of like the mississippi river delta um okay so show of hands who thinks that mars is the photo on the left side of the screen and who thinks mars is on the right okay you know like getting pretty good at this so what's interesting as again we have the exact same feature caused by water on both plants what's particularly interesting about jesuva brader is that that is where we just landed last year uh the mars 2020 perseverance rover and i'll talk more about that a little bit later at the top but the rover is currently surging around this delta because we think it might be a great place to find life uh an ancient riverbed leading into an ancient lakebed maybe there's some fossil evidence for something preserved there but we'll get to that another piece of evidence that there was once water on mars is actually the color so mars is called the red planet because the entire surface has been oxidized or rusted the same way that if you leave your bike out all winter in seattle your chain might develop some rust on it from all the water but when we look at these dried riverbeds and lakes and deltas all the water is gone which just begs the question of where did all that go how did so much water disappear imagine how much water would take to rust the entire planet so to start to answer this we'll move on to the next chapter five and zoom out a little bit and since there's no actual fire on mars there's nothing to burn we can also think of this as maybe heat so though there's no fire on mars there is fire somewhere else in the solar system that provides mars with most of its heat does anyone know what i'm talking about the sun exactly so here we have earth and mars and mars is a little bit further out from the earth and we can see that as you get further and further away from the sun it gets colder and colder just like if you were to move away from these heat lamps you would get colder and colder and colder and if we zoom in here on earth we live in this perfect goldilocks zone where we can have all kinds of water we can have liquid oceans we can have clouds up in the sky at the north and south pole we have ice caps but mars which is further away and colder it has ice caps we can clearly see from space but not much else you would think that because it's so cold it's below freezing for most of the year that all you would get is ice and nothing else except i wouldn't be here if that were true i'm here to tell you that there is actually something happening at the surface that can let liquid water exist in very small amounts which brings us to our fourth chapter so to think about how water can exist in such a cold and frigid place let's transport ourselves back to winter up in the mountain passes maybe when the there's a major snowstorm and the roads freeze over completely how do we fall out the roads and make it safe to drive again we add salt exactly so adding salt to ice causes the ice to melt into salty water the reason is that salt lowers the freezing point of water and allows it to stay liquid even at colder and colder and colder temperatures um and you know we sometimes do this really well and sometimes not so well like this photo it's like last night's storm but what's interesting about mars is that it's we don't have to spread the salts ourselves the salts are naturally occurring all over the entire surface and you might when i say salt you might think about table salt but there are other kinds of salt too for example you might have heard of epsom salts which is just a fancy name for magnesium sulfate uh there are also nitrates which we use in fertilizers and perchlorates which we use in flares and fireworks all of these salts have been found by rovers and landers just naturally occurring on the surface which is pretty weird so these salts can actually form liquid water in a process known as deliqueness if you've ever left table salt out on a warm summer day you might have noticed that it starts to get clumpy and sticky what's happening is that the salt is pulling water vapor out of the air and starting to dissolve into a salty brine and that's exactly what we're seeing in this video we have concentrated balls of salt that are so they they like water so much that they're pulling it straight out of the air to the extent that they're dissolving almost entirely into little bubbles of brine and this process is happening on mars today in the dirt which is what makes it so excited it's the one way that we can have liquid water that then stays liquid because the salt lowers the freezing point so to recap what we've learned so far despite cold and dry conditions water can exist on mars today because of the humid air the salty soil and the sun's heat so to use that knowledge let's ask two even bigger questions how much water is there on mars today and could that water actually be useful for life and you can think of this as the part of the story where the the character learns to control all five all four elements and but instead of saving the world we're just going to design a mini blue spare and so this is an experiment i've done in the lab at university of washington i've taken my four different elements and add them all together in a container i like to think of it as having a little piece of mars in a jar so i add in my thin humid air some salty rusty dirt some temperature that i can control with the knob and the water through either humidity or through salty solution and it's basically like having a little knob and i can adjust the knob for each of these parameters to change a whole bunch of different conditions and simulate all these different conditions that might happen on mars study what happens to the salt and the water so to walk you through my process a little bit we start with the air really low like i mentioned the air on mars is extremely thin then i can add in the salts and see what happens is that salt just like we saw in that video earlier it pulls the water vapor out of the air and starts to dissolve into a brine then if i change the humidity maybe add some more water vapor into the air even more water starts to dissolve into the soil the last part of the experiment i changed the temperature and i crank it down to extremely low temperatures there we go um to see how cold can these little brines get before they freeze solid because life needs liquid water it's not as it's not as happy with ice so i find the point where that all changes to ice and what i've learned from these experiments is that mars's dirt is a lot wetter than we once thought but the next question is is that water actually useful for life or is that just you know great you have a little salty dirt on mars and the reason we care about whether this is an uh whether this could support life is because we have rovers up there right now exploring mars and if there's life up there we want to know we want to avoid a situation where maybe we didn't sterilize the spacecraft properly and there's maybe a hitchhiker on board that might act like an invasive species and out compete mars and life we would hate for that to happen so we really want to know could these brines support life and to do that i have this scale here that goes from zero to a hundred percent of how salty is your water at the very bottom at zero percent it's pure salt just dry there's nothing that can live in it at the very top we have pure fresh water think uh babbling broken mountain fresh off the glacier something like that so think about now the dead sea which is one of the saltiest bodies of water on earth it's called the dead sea because it's so salty that no fish can live there no plants can live there um so it basically looks like nothing can live there just shout out some numbers where do you think the dead sea falls on this chart from zero to a hundred okay if you said about 67 you were the closest so even the one of the saltiest bodies of water on earth only gets down to about 60 percent 67 percent on here and if you scooped up a bucket of water from the dead sea and looked at it under a microscope you would actually see that there's still stuff floating around in there it's not totally dead it's just the life is too small for us to see with our naked eyes but as we get saltier and saltier there is an absolute limit for how salty life can be before nothing can survive and that's at about 60 percent here anything below that life just doesn't have enough water to do its basic functions so we've never seen earth life been able to reproduce or grow and conditions below 60 percent so thinking back to my experiments where i created brian's in the lab where did those fall in this diagram i found that mostly they fell below this threshold for life as we know meaning that for most of the year and under most conditions brian's on mars would probably not be habitable for earth life which is good because that means we won't be it won't be very easy for us to spread um contamination there accidentally but there are certain conditions where the brines were above this threshold and we could have uh conditions for for life um or it could be that microbes on mars are unlike anything we know of in this threshold for earth life just doesn't apply maybe they are very very happy to live in salt we just don't know because we never actually found anything again so if the briney soils are um completely devoid of life then maybe we could use that for future human exploration of Mars and to explain how we might be able to get water from this um if you have a salty soil you can't really like drink that so you'll have to extract the water somehow you might use heat to evaporate the water leaving behind the salt and the dirt and then that water vapor can be re-convinced out into water which our future uh human explorers and mars could use to survive which is pretty cool okay so that's everything that i've done in the lab so far but that's great it's just in the lab what about actual mars right let's get out there and actually test it and so what i'm showing here is the perseverance rover which i told you we'd come back to i am on the science team for one of the instruments on the perseverance rover i work on the pixel instrument which is short for the planetary instrument for x-ray lithochemistry a lot of word salad but just to break it down litho means rock chemistry and studying what things are made out of uh the pixel you can see here on the robotic arm of the rover it uses x-rays to study what rocks are made out of and to explain how it does this i had an analogy if you've ever had glow in the dark stars on your the ceiling of your childhood bedroom or maybe in your current bedroom whatever um it works in a pretty much the same way uh you shine a light on the glow in the dark star it takes in that light and then when you turn the lights off it re-emits that light in a process called fluorescence if you have a camera you can then take a picture take a picture of those glow in the dark stars and see oh yes they are there and they're glowing in this color and i know what they are they're glow the dark stars so pixel works in the same way but for any kind of different rock um the pixel instrument is up here this white box and here i'm showing rocks that fluoresce in a color that we can see but instead of visible light pixel shoots out x-rays and the rocks bounce back uh light corresponding to that x-ray and they might not be in a color that we can actually see but pixel is better than the human eye so it can actually pick up all these different colors that are outside of what the human eye can see on its own um so they might not glow as fantastically as this but two pixel that's that basically what it sees and what's great about this is that every single element and here i mean elements like on the periodic table every single element glows in a very very specific color so by pixels seeing what color the rock glows back it can tell what that rock is made of and here i have a picture of pixel actually in the field in action we see the robotic arm is hovering over a rock here on mars and i have a little diagram on the right hand side to explain what's happening uh this was actually just a few days ago so this is a very much an active mission that is right now doing things on mars you can keep track of it uh if you just google like uh mars 2020 first appearance rover you can every day images are sent from the rover directly published straight online um and that's where i got this picture and many many more so if you're interested you can look that up but basically the way that pixel is going to work is that it shoots the x-ray at the part of the rock and that rock is going to bounce back some fluorescence and based on the fluorescence that comes back from that rock pixel can see oh yes this rock is made from iron and silicon but what makes pixel cool and new is that it can do this uh many many times across a single rock and get a really good map of what that whole rock is made up so maybe it moves to a different spot in the rock and does the same thing over again but this time it detects sodium and fluoride which you might recognize that's the formula for table salt so we can see that if pixel sees a rock with salt in it then we can go back to my experiment from the lab and see what were the conditions like on mars at that time what is the salt that is being detected and what does that say about the water that's there and its ability to possibly hold light overarchingly but yes that's not a word but beyond just looking for salts pixels also has the goal of searching for light on mars and i don't have any exciting announcements to make at this top because pixel is the perseverance rover is so new it's only been on mars for about a year but with any luck we'll have years and years and years of more exploration to do with this robot so definitely stay tuned for more exciting discoveries as they come in and just to wrap up i wanted to talk about something that's really important to me oh no it's it's good it's supposed to do that yeah i wanted to talk about something that's extremely important to me but it's often overlooked in planetary science and astrobiology you know we just heard from lucas that we sent a robot to to enceladus to scoop up some of the water there we i told you that we sent robots to mars to look for life and in you know the popular media you might hear people talk about sending humans to mars one day colonizing and i want to pause on that word colonization because it's something we don't really think about a lot uh in planetary science you know tech billionaires might talk about colonizing mars and we might read about it in sci-fi books and it's really entered in our popular imagination as the common sense next step for our mars program but i want us to stop and reflect on the history of colonialism here on her so um i am very worried that one day we will um just take the colonial practices that have built this country and just kind of export that same model into outer space without learning from any of our mistakes i really think that it's important to study history study what we did right what we did wrong learn from that so that we aren't just blindly stumbling forward continuing to make same mistakes again and again and again if we go to mars and we discover life we discover some valuable resources are we going to just extract that extract that trample over that life and not worry about anything or are we going to stop and think ahead of time about how to uh appropriately um explore and settle maybe mars so the good news is some scientists have started thinking about this um this is a white paper published recently about ethical exploration and anti-colonial practices in planetary exploration um and the scientists laid out a bunch of ideas for steps that we can take now as we prepare for our future in space just to give you some brief uh brief summary environmental stewardship thinking about how we're going to be interacting with these environments are we going to be polluting them contaminating them with earth life um the moral consideration for microbial life um no matter how big or small life is is life itself valuable to us what is the value of it regardless of whether it's intelligent or whether it looks like us um what do we owe to life that arises on other worlds and lastly the profit systems that we have in place and establishing regulations so that we're not just going to mars bulldozing everything and taking what we need and thinking about the consequences later but the problem with this is not a simple solution um i think this has really become something that's become part of the popular imagination at this point and it's not going to be scientists who are making these decisions eventually it will be private industries it'll be governments and i really wanted to bring this up with you all today because i think it's an important thing to start having these discussions now because it's too late to turn back the clock and prevent the harms of colonialism on earth but we're born at just the right moment where we can break the cycle and move into space with a new model for how to interact with different environments and so i point a term for this i call it exo-viron mentalism and exo-viron mentalists is someone who advocates for the protection and preservation of environments and possibly life on other worlds so i'm hoping today that you will all start thinking maybe like exo-environmentalists and considering how to uh as we go forward create a more just and equal world for us in outer space thank you all right i'm i may use the weird mic here for a second um thank you andrew excellent talk we have time for questions so if you have a question for andrew i think we've probably got time for three or four of them so i'll go ahead and let you choose whose questions to answer um please repeat the question so that the that the livestream gets it sure thing here in the middle yeah so to repeat the question we're already sending trash to mars eventually robots will break down and we don't bring them back when they do that so what are my thoughts on that um it's a difficult moral question because recently we started um getting pictures back from perseverance rover and we found the entry stage we found the parachute that was just sitting there on the surface of maras and it will be there forever there's nothing to break it down um we have to weigh the pros and cons i think is how i think about it the amount of science that we are getting back and the amount that we're learning about not just maras but our own planet and what uh what our planet was like early in its history it's maybe worth that trade-off of a parachute sitting on the surface but as that's okay for maybe like a few missions but as more and more people get the ability to go to mars that is something we're going to have to think about if everyone's launching their rover to mars and then just leaving it there to decay what impact does that have on the environment and is there a way that we can mitigate that these are questions that we're going to have to address in future yes okay so the first question was about the salty soils what can we actually grow in the salty soil i wish i had an answer because i'm not actually the biologist um but i did see a study recently that they were able to grow uh some kind of plant in moon dirt in actual rocks they have returned from the moon so i do i don't think it's a stretch at all that one day we will be able to grow something in mars's dirt despite all the salts um and even if even if not we can remove the salts maybe first and then use the dirt and then the second question reminding