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tv   Mars Rover Scientific Discoveries  CSPAN  June 7, 2018 11:12pm-12:10am EDT

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public service by america's cable television companies. today we continue to bring you unfiltered coverage of congress, the white house, the supreme court, public policy events in washington dc and around the country. c-span is brought to you by your cable or satellite provider. >> nasa scientists discussed new discoveries by the us rover. then as a team was found organic compounds that suggest life might once have been possible on the red planet. this briefing is one hour. >> we are live at nasa from two locations. i have doctor paul who is our director of the explosion division and principal investigator. i also have jennifer who is one of the coolest titles i know at nasa with sears and astrobiology
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spring we also have the jet apostle laboratory in california and we have doctor webster and [inaudible] who is the project find us for the mars science laboratory. my name is michelle and i'm an astronomer here at nasa and one of the things i was at the vet today is that none of us live in a vacuum we all have our own social media accounts and are aware of the interest that this has generated. will tell your now we are not announcing today is the detection of life. we cannot talk about that but what we are talking about our exciting new results that have to do with organic molecules. we understand organic molecules are the building blocks of life and if we don't announce the detection of life the discoveries we talk about are important next step in finding out whether mars was once habitable or still might be
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habitable. i will lead off with paul who will talk with us about what we know and don't know about mars. paul, straight up, what have we found? >> exciting times. i will reinforce what you say. life, organic compounds on earth just the imprint of life that is natural for us to equate organic molecules with finding life on mars but that's not the bottom line of trying to get out here. the bottom line is we greatly expanded our search for organic compounds which are fundamental to our search for life and it's interesting because of two complementary results which is organic from billion -year-old roxie got trapped in a agent lake and billions of years ago and the second is the simplest organic methane in the atmosphere and those two results and chris who is lead author on these papers will talk about. let me add context. there was august 2012 more than five years ago we barely came into mars and there was an
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exciting and we landed on great engineering team that got us there and the objective of the mission was to explore a capital environment and mars and we found clays that were formed by water and curiosity that is measures the elemental compounds of the rock and what we've always done the we found many things that we will talk about today that we essentially found out very early that this was an inhabitable environment and a lot of them have been there for a long time. we found interesting things for how old the rocks were and
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measurements of lifers heavy elements and how the atmosphere has escaped over billions of years so we kept going on the search for organic and found nothing before and found simple organic molecules and we greatly expanded the results. >> paul has mentioned some of the results in some of it is important. throughout the broadcast as you see me looking down in my at that we are taking life questions. you can use # ask nasa or if you join us on facebook but your question in the facebook comments and will get to as many as we possibly can. will take questions lie from the media later in the show. if you are live looking at the questions jennifer, tell us about the significance of finding organic life and mars. >> we found it in an agent like
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bread in those could have come from life. we don't know that there was life on mars and the organic molecules we found are not specifically evidence of life because there are other sources of making those molecules including things that are non- biological in nature, things like meteorites or even rock processes. we can attribute geology to life without making organic molecules. the information we have doesn't tell us which source is responsible for what we have. >> thank you. another one of the major detections and discoveries to talk about involved methane on mars. we think of it as a simple gas and we will talk to chris webster and chris is instrumental in the discovery before of methane spikes and it went up dramatically on mars. can you tell us about what today is different and noteworthy
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about mars? >> every chapter in the story of methane on mars has been a surprise. from sometime ago the report was clues in the atmosphere and there were reports of patches when orbiters looked in spikes as you just mentioned. everyone of them was a surprise and frustrating because none of them repeatable in time or space and they seem to show that methane was misbehaving and it was sporadic or almost random and patches were showing up. today we are announcing the discovery about repeatable identifiable seasonal pattern in the methane measurement and we can look at the graphic and see that in the lower background level because most of the time were not looking at spikes and we see the slope back on level and you can see from the [inaudible] there is growth in the big surprise is not only do
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we have this wonderful repeatability but the seasonal cycle changes by a factor of three and that is a huge change completely unexpected and what it does is gives us a key to unlocking the mysteries associated with mars methane because now we have something to test our models and our understanding against. we will hear more about that later. >> one of the things you hear about is organic and a lot of people are familiar with the different ways so i will talk to jennifer. tell us a bit about what we mean by organic and tell us what is the significant about finding this on mars? >> to a chemist it is simply carbon and hydrogen. sometimes you have so far and nitrogen oxygen but it's just that structure so what were not talking about is molecules that specifically come from life and were not talking about the organic stuff that you find at the grocery store.
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>> this is one of the engineering feats and we are falling molecules. can you talk to us about how we identify these molecules on another planet in mars? >> the curiosity rover drills into rock layers and when it does it produces rock powder and that rock powder gets put into the oven and he did. when it is heated it produces gases and they get whipped up into the spectrometer in here you can see the gases coming through tubes in the enter into the chamber where electrons ionize the material and as a result if you molecules that are split into tiny pieces and the spectrometer can identify what those different pieces are can put them back together to understand the original molecule was. there's another feature that has gas chromatograph and that looks like this.
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it's a really long tube and it has a hole in it that is about the width of a human here and the column allows molecules to go down the long tube when they come out the other side they come out one by one and when that happens they go into the mass spectrometer and we can identify individual. the gc's on sam or built by our french science for international research and it's because of these that were able to identify certain molecules that we are reporting. >> this is from were talking about drilling to the surface of mars and how far into we go and how far deep? >> 5 centimeters. as far as we can go. >> will talk more about why that is significant in and be more interesting things brother down. i remember well the landing of the rover is on the best
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mornings in my life when you show me that coil and that had to land on mars that and there was a big snap of g forces and we land using incredibly sensitive on mars and we -- let's go to [inaudible] at jpl. tell us about the curiosity rover. >> probably wondering what you see behind me is the test model of the curiosity rover. it's a twin that we use for testing here on earth. the one on mars is in a place called gail crater and we sent it there and it's about 100-mile diameter hole in the ground that formed on a giant impact about four years and 10 million years ago. what true us is the mountain in the middle. that was not there when informed. in fact it formed by rivers and
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streams and deposited into the story lake that filled the crater and as that sediment settled it build up the layers that made up the mountain. each layer is younger than one below it so by climbing this mountain we can read the ancient history of mars. climbing is what we've been doing that most of curiosities mission. we are now a thousand feet and that's as high as some of the downtown discuss grippers of los angeles. we get an amazing view. we want to drill through each layer of this mountain. the samples the gender scribe were taken in 2015 and it's taken us a few years to get an understanding of these results as we can describe them to you today. >> there was something fascinating about the rocks and evidence of water so tell us why this was elected. >> we had hints that water was
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involved in interacting with these rocks because of the orbiters that have been in mars before and for example there's a mars reconnaissance and mars express and those instruments both of the orbiters had instrument capable of detecting clay minerals so we know that some of the layers may have clay minerals which means water interacted with them but we weren't sure if rivers and lakes existed in curiosity has now shown that it has existed for a long time, hundreds of thousands if not millions of years. >> john from facebook says tell us more about the appear repaire to the arm. space is hard in her all the way on mars hotel is how you got to fix this from millions of miles away?
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>> this is worth the press conference of its own. it's coincidence that we have this amazing me to tell you not only about the drill but about the wonderful results from the last few years and exploration as well. in late 2016 we realize that one of the main motors of the drill would no longer functioning reliably in this basically meant the drill was dead and a big part of what we had a, on mars we can no longer do. it's not that we fix something or tweak something but we had to invent a new way of drilling. that is a remarkable story that i have to give all the credit to the engineers who do that work. for about one year and a half they try to fix the motor and invented an entire new way of drilling that did not use the motor any longer. just this week we achieved success. we have successfully now drilled and analyzed samples and our laboratories once again. >> we talk about drilling down in analyzing so for those of you who are fan of organic chemistry, let's dive into the details. >> we detected a variety of molecules and others that
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included carbon change. here's an example. protein. these are representative of molecules small little bits and pieces but because we see these coming off of a sample at high temperatures but they are telling us is that it's a part of something larger. this is something that we call [inaudible]. we find examples of this on earth in things like coal and black shale. these two things. we also find them in meteorites. they are common. this tells us there is organic material in the rock in a different form than what was detected. what it means is that it was in a robust form and this resistance was resistance to change. this is an example from the data that we get from sam that we can tell after the molecules go
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through the column and the actual structure. we use this information to figure out this structure. here we have four carbons and a sulfur. sulfur looks like this when it is in rock form. but in the sample the sulfur is probably in the organic molecule itself. that is important. sulfur is material that can help bind all the small pieces of organic molecules into something really big like that large molecule i showed you. sulfur helps to resist oxidation. that is important for our discovery because we are looking at ancient rocks and we found organic materials inside them. however we drilled in the top 5 centimeters. in the top 5 centimeters the surface is exposed to a lot of ionizing radiation that generates free radicals and accidents. all of those degrade organic material. the rock has been sitting at the
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service for an extended period of time and were talking tens of thousands to hundreds of thousands of years. that's a long time for these changes to happen and there were a lot of people who thought it would not find all the organic molecules that we did. for instance, biking started this quest back in 1936 looking for organic molecules. curiosity has continued that quest and now we have a diverse set of molecules that we can start to understand a little more about how this material is preserved and why we might look to get more. >> you are working on mars it's hard. lotta people know that they have no atmosphere compared to the earth and has very high radiation levels. we have this laboratory working on mars so the radiation from gets about how far down into the soil?
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>> is coming from the sun and the galaxy. it can extend about 1 meter and a half, maybe a little more but there are places you can go deeper down the we might pass into molecules that are not disrupted by the radiation itself. this other rover is the perfect example. it will drill 2 meters deep. it will have opportunity to examine materials at the service and on the way down to see if there is comparison. we will learn how important it is to where we have to refine our analysis and we will understand the preservation issues and how it affects things at the service compared to things further down. most importantly after our bio signatures inside that organic material associated with it we will have a better chance of
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understanding that if we get the materials that are not exposed to radiation. >> we are finding interesting chemistry right on the surface of mars. it's a promise of more to come if we can get deeper down. as we look at the crater how do these organics get here? your finding them on the floor so how did they get there? >> we are looking at a lot of layers put down in an agent like. as previously discussed that had been there a long period of time and hundreds of thousands, maybe even millions of years, we are not sure but there is lake sediment and organic material can come into that lake through rivers or windblown in or they can be formed in the actual lake itself by things like biology. ...
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>> we do not have enough information to tell what the sources and helicopter. >> when you look at the organics on mars we talk about the seasonal methane. are your discoveries all related to this? >> yes and no. if you take the organic detection and you generalize it we have sound organic material and that might be throughout the grander area. that is carbon that could go through various processes and make its way to the surface, and turn into things like methane. the detection that chris will talk about is the modern-day as opposed to ancient like i discovered.
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>> discovered a chris webster. tell me a bit about the seasonality of methane. give us details about this new discovery. >> i thought i would tell you right away that we have seen the seasonal variation. we tried to look at the data and come up with an explanation. we have been able to rule out some of the sources. we don't think the delivery of the dust can produce methane in the atmosphere, we don't think it's so important because we would see maybe 20 fo 2020%. instead we see a massive change in the methane signal. we look at the data and the idea of subsurface storage. so way under the ground the methane was tracked might be
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tracking through other material. we don't know if that is ancient or modern. it could be either. we don't know if it was created from water rock chemistry, or by microbes. we cannot distinguish that. but the methane leaks will come up to the surface and find his way through cracks and fissures. when it gets to the surface than the surface temperature can modulate or amplify the release of methane. it's next setting time because we have the seasonal cycle that constrain some of the theory. >> i want to talk more about how to distinguish the biological or nonbiological methane. tell us how you detected this. they actually brought martian soil and soil into this.
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>> we are ingesting from the air. as you look it curiosity, there are two inlets in these valves allow the atmosphere in. once it gets in to those, we have tiny little infrared areas that go 81 times and that amplifies insensitivity. when you look at the laser light you can scan it look at the spectrum of methane. it's so high that we see a fingerprint of three lines together that can only be from methane. the signals come from methane and nothing else.
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>> let's go to another scenario. one is that we have a cycle that is more active in the summer, is that the idea? >> we cannot distinguish that. once you get the hydrogen released in both reaction can be catalyzed through the microbe. >> if you have water that is interacting you can also get similar methane tracked in the foil it comes up in the summer? >> yes.
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>> we're hoping that we will get more results in the future on this, especially on other missions. a source testing for the biological, there are several more steps that can be made. we can look at other ratios that could suggest biological activity. we can look at the surface the maybe one day we'll see up the large enough to see that. >> there's exciting ways forward. at this moment the biological option is being held. >> the exciting result about the methane on mars, i want to say thank you for joining us, we are live at nasa will take your
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questions five. if you're in social media use the # asked nassau. if you're joining us on facebook will get to as many of those as we can. we talked about the latest results, one thing i want to mention is that we have a mission to mars on the way right now. we launched the insight mission. and it went live on november 26 of this coming year. it's looking at a different definition of the word light. there seen if the planet mars is still geologically a live. whether any activity below the surface. how quickly are they losing . look for that this fall. we'll have another landing on mars to see what the activity geologically us. i want to make one more trip
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back. the amazing thing about the seasonal variation of methane is that you need to be there for many seasons. tell us about the lifetime of the curiosity rover. >> it's wonderful to have this discovery that took so many years to not only take the measurements but analyze as well. measurements -- we have taken about 30 measurements with this instrument over the course of the mission. we are planning one on mars today. without having the rover survive for six earth years, three mars sears, we would have never been able to discover the seasonal patterns that are at the heart of what was described. the final a few more words to
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jen's discovery. one thing that makes it so special is how it fulfills the role that curiosity has play. nassau charge this mission with detecting organics on mars. we've done that but it was more than that. we wanted to understand how organic molecules was incorporated would be there for us to discover all these worlds later. one environment that allowed it to resist that and that's remarkable from jens results that she can determine what types of molecules and environment allow them to persist. it's not only important for curiosity but also for future marsh missions to see direct
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signs of life. what this does is gives us confidence that when the missions get to mars, there could be something for them to discover. >> you're saying that martian years longer than the earth here. tell us about how the martian day is to an earth day. i think you have personal stories related to this. >> there's no less similarities between mars and earth. in some ways it's coincidental. mars is a 24 and a half hour day and a tilt of about 24 degrees which makes the days and seasons earthlike. makes it interesting to operate a rover. the best way of doing that to live on that before your out there going crazy.
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>> 40 minutes later every day that be disruptive. >> someone just asked us where are you? where you standing? >> read a place called the mars yard. we are in a shed where the model of curiosity lives. behind us is the engineering model some people call her maggie and it's much like one on mars in terms of the software and electronics and instruments. this can drive out into the yard and we use it for tests. this is the model that was used to teach the rover how to drive and navigate. we can use it for many things that we don't want to use the precious time and resources. >> will start with questions.
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we talked about landing this amazing rover on mars. tell us a story, how do you get this? >> let me have you throw question my direction first. and what did you do this morning paul. >> what we did this morning was look at data that came down from curiosity that was deposited into sam and his been months and we are in the process of getting the drill back in order. the search will go on. getting back to your other question witches what it took, the san instrument is complicated. it took a huge team of scientists, engineers and software programmers. it's an international team.
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chris webster's team developed this, french colleagues developed it. they were calling in and supporting operations of our instruments. we spent several years putting it together. we put it in environmental chambers and match the conditions we would have. that eventually we brought it to the jet propulsion lab. this shows sam the gold box just being lowered into the rover. rover is upside down. then we do more testing and put it in an environmental chamber.
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when we're sure everything was perfect it was ready to be shipped. so you see everybody there in bunny suits, the reason there in the white suits as we don't want to bring our skin oils to mars, cousin jen would have to report we were finding things that look like they came from -- it took a lot of work. great teamwork in several nations joining us. >> someone asked how do you verify the experiments have not been compromised? >> we bring along standards. for example we do it any good analytic, status, we run blanks. if were looking to make sure none of the organics of the instrument of producing the signals we see, we do a full
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sequence but we don't put sample in. we work hard to make sure what we're seeing is from mars. there were confident. >> there's many questions coming in. welcome to give us any questions. from facebook put your questions in the comments. there several questions from many people about can the methane ever be used as a fuel for future missions? >> of course there is not right now their low background levels. methane is also a useful as a fuel. the ability to extract it from the atmosphere would not be efficient.
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but it could become a new ballgame. his speculation at this point. >> we have a question about if you could add just one more thing to the rover what would it have been? >> that's a tough one. is probably a list of things. i'm gonna deflect and say the next thing we want to do is forward to the mars 2020 mission. building on the possibilities of life and looking ahead to having instruments on mars built to look for the signs of life. >> this is a difficult question. we have organic molecules, what signs would you look for for life? >> were it's based on molecules.
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before going to look for life, the first thing you want to do is look for signatures associated with organic material. those part of the reason it's significant we found that in the first place. it helps us guide where were going to look. in the signatures there might be things about the chemistry or how the material is stuck together. how their packaged, there's a sweet of chemical and physical things we can measure that might indicate signatures of life. >> one of the most northern spring in the cold area than this pattern showed up and show the length of a pattern change. so those are the type of things we might look for.
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>> there's another experiment we have not used yet, if those types of things i left behind in the organic material would come across we will come across more, perhaps if it's the right sample maybe we will get some hints. >> were going to try to have an audio feed at the moment. >> our first question is from chris. >> thank you for doing the call. if you could translate this in ways my grandmother could understand why is methane so exciting, what is so intriguing about it that the molecule is different than what we already
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knew. >> should go to chris for that question? >> i would start by saying when you have an oxidizing atmosphere needs to reduce compounds like -- it's always very exciting because 95% of the methane on earth is produced by biology produce from termites, rice patties, cows, or sheep. because of that, there's an interest in mars methane the potential biological origin. that's true because we know it can only last for 300 years. so if you see it something is being released or created. i'll hand over to paul for the second part. >> on earth, like chris mention,
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most comes from the biology of rice patties and a lot of different processes. most of the oxygen on earth comes from biology, billions of years ago the bright bacteria started cranking away. in our atmosphere we have methane and oxygen. that's what some of the folks will be looking for combinations of oxidizing that might be evidence of light. >> we have another question for the media. >> the next is nancy. >> hello, there is a similar
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announcement methane and organic materials in 2014, how is this announcement different? or how have you built on the findings from 2014? >> 's a very good question. in 2014 we reported the discovery of coordinated molecules. it was a significant discovery. the first time were able to confirm organic molecules on mars. we've been looking for this for a long time in the hopes we would find it with an instrument in 1976 and then with curiosity landing on the lakebed. we were left with, what is this
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mean? it's not what you typically find in natural samples. we are not sure what the significance was. it gave us motivation to keep looking. there had to be other layers and we wanted to find more organic molecules. we drove 4 miles away to the lowest part of the crater. we got to the base of the mountain. the first layer we looked at contained organic material. we have expanded upon the inventory of the organic molecules and have a better sense on how they were preserved in the first place. >> your report showed significantly greater abundance than we had detected before. in almost every experiment we do, as we heat up the sample we see a big oxygen signal. that comes from the minerals
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that contains chlorine and oxygen. then that can react to some of the organics. which ended with part of her analysis was look at the high temperature release of organics that may have escaped. there are still things were not seen. thus motivating our desire to get back to look for comprehensive suite of organics. >> would you like to continue your answer about what was detected before. >> is very different. in the past we are seeing things we could not understand and we had ideas about them but cannot constrain them. now we have measured the background level over two years.
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we know the total amount of methane in the atmosphere is constrained by that. a low average value. it changes a lot but the total amount is low. that constrains what is mixed in. it's a very important observation. the fact that it changes so dramatically has got to be duplicated by models that explain it. we do think that the spikes are related, quite conceivable that they go up to the surface are the occasionally causing large pulses of gas to be relieved. >> thank you. >> will go to the audio line the. >> thank you. your line is open.
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>> as i understand this, the take away is confirmation and also a detection of -- in the soil. so what follow-up investigations specifically from the europeans could support and add to this? specifically, and orbits are presumably can do the kind of isotopic analysis. can you see that contributing? and secondly in the future they're talking about -- is this the same as msl.
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>> let me say that it's great to hear somebody say methane. starting with the mission, we are proud of the work are tainted to deliver a mass spectrometer which is planned to launch in 2020. we greatly expand the techniques we use to look at samples that, from 2 meters below the surface. the first thing is that we use the laser to put a pulse of energy into the sample, then we let the ions at the very high mass range. we can do things like find a high mass peak and we can do --
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we can break the molecule apart into its constituents and tried to get at the structure. we also have a gc ms and that is a contribution from her french colleagues. they're good at understanding how to do this separation of gases. they do this chemistry that tries to pull out interesting things like a mean amino acids differently. they tried to control that a little bit better by having basically a container that will break apart at the right temperature and then to separation. the technology has advanced. we'd be interested in finding
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the right and left hand of amino acids. they're not equivalent, but immediate rates are largely equivalent. were trying to sell that problem as well. technology advances in our ability to think through advances. maybe chris should talk about what the european corporate or what they hope to find. >> the exciting thing is that it's called's going to look at gases in the atmosphere but especially methane in particular. they started to make measurements. were waiting to see what they find. by masking it globally they'll be able to relate their measurements to ours.
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one thing they could do is a large plume is somewhere even though they don't have a lot of resolution they could pinpoint in the area that seems to be associated with the increase from the surface. that would be exciting. who tell us where we need to go to get the better signals. you asked about the carbon 13 ratio. there's 100 times less carbon methane than regular methane. if you want to measure that from 1% your stock with high sensitivity needed. so they most certainly would make that measurement. it will be a challenge. >> have limited time for questions.
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i want to go to some middle school students. they're asking that's about the implications for future colonization of mars? >> it could. when you have organic material and there are it could be wider spread. perhaps those of be a resource for humans. there could be organisms there that we don't know about. there could be organic materials as fuel for farming, they need carbon to turn it into their own biomass. there's other ways to use it to generate fuels that people would use. they have not been fully investigated. it's an open book.
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>> so is it possible to bring samples back from mars? >> that's a great question. >> we hope so. one thing that were working on is the mission called the mars 2020 rover. it has some sophisticated instruments that it's bringing with it to look directly for signs of life. it is proposed to bring samples back to earth one day. something to lance a rocket on mars and gather the samples, to bring them back to the rocket and then blast off and then rendezvous with this space that we have put in mars orbit and bring it back to earth.
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that's a lot of cool technology that can be invented in the next couple of decades. >> this leads onto that. you have an active mars exploration program near trying to figure out what the best places to land next would be. >> one of the big questions is where we going to find organic carbons. there's some environments that we understand on earth that could be good places and then also good places for life. so lakebed is a perfect example. but there's other systems were have fluids and gases coming out can. create chemicals that can be used. we see these in the ocean on earth. there are rocks on mars that suggest there's ancient systems.
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right now, the larger mars community is talking about where they want to go. these are some key scientific motivators for choosing sites. >> we have two things, a huge amount of data with very capable orbiters. then we have imagers and we can see a few feet that's one tool we use. one thing that brought up was minerals that were hydrated that had water. that was a clue there could have been a lake there. on earth it's very hard to find old rocks. earth is active still, volcanoes are going off in the landscape keeps changing. it moves the continents around.
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half of the surface was very old. we can get at the ancient history by landing on the surface. >> the modern landscape is a very ancient one. working to go to another media question. >> i appreciate the time. [inaudible question] [inaudible question]
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>> i believe he's asking about how the discovery will fit in with the legacy of the mars curiosity rover in your view of that? >> that's a great question. sometimes being evolve so deeply in the day today you have to look at the bigger picture. where think about it is that we have a role in this ongoing exploration that's been going on for 50 years and will continue in the future as we get closer and closer to life on mars. and eventually sending humans there and maybe colonizing mars one day. we didn't know if mars is have little before the we went there. or that lakes could survive. we did not know the extent to
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which organic matter was present and could be preserved for us to study today. those are big questions the mission was designed to address. with these results i cannot be happier and how we have been able to meet those objectives and provide them as materials for future missions when designing where to go and how to accomplish what they're designed to do. >> thank you for taking my question. i wanted to ask about the -- where methane is coming from. to think it's a summer temperatures that are warming it up? >> you asked about class rate.
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there is a class rate stable on mars that's created through the high pressure. they could be a source. let's get under the surface by several meters and below that, you don't have a seasonal cycle there. so the class rates might be leaking. it's only when it gets to the surface where the surface temperature has a seasonal cycle that modulates the release. >> that's all the time we have. if you submitted questions that we do not get to spend the next hours and days trying to get to as many as we can. thank you for joining us. have a great day.
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>> this weekend on c-span, saturday at 10:00 a.m. eastern, ceo, alexandra next testifies in london on the misuse of data and privacy concerns. sunday 10:30 a.m. a hearing the sexual abuse of olympic and amateur athletes. on book tv on saturday at 7:00 p.m. eastern, former president bill clinton and james patterson discuss their collaboration in writing, the president is missing. former u.s. ambassador to russia talks about u.s. russia relations since 1989 in, from cold war to have peace. on c-span three saturday on lectures in history, chilean, on the growth of conservative influence on form policy. sunday at 2:30 p.m., jill and
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her book, stories from trail releasing women lawyers. wash the networks this weekend. >> next week, live coverage from the u.s. north korea summit between president donald trump and north korean leader, kim jong-un. then join "washington journal" on tuesday and wednesday for analysis and comments. watch live on c-span and c-span.org. >> today, stephen gross the chief actuary testified about the solvency a retirement program at a house hearing. this year they'll pay more in benefits than it receives your payroll taxes. a recently released report says the social

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