We present here a transcript of the science presentations delivered at a March 12, 2013 press conference at which NASA Mars Science Laboratory (“Curiosity”) scientists announced that they had discovered evidence of what had been – how long ago may not yet be precisely determined – a “habitable environment” on Mars.
The discovery – which is NOT the discovery of “life on Mars” – is another step forward towards that goal. Having now found multiple proofs that water both flowed and pooled on Mars for long enough periods of time to have produced mineral-rich clays of a type very similar to those on Earth (in which, some scientists speculate, early multicellular life forms may have evolved on Earth), the NASA team will now search to confirm some of the most intriguing discoveries recently made, which their Principal Investigator team describes below. These developments have come quite rapidly from this mission; we expect that there will be many more exciting discoveries made by the Curiosity team in the very near future – and as soon as they occur, we will try to bring the news to you.
As always, this transcript was produced by ourselves from the video on NASA’s USTREAM channel. It’s still a nearly complete, uncorrected partial transcript; we were not able to complete Dr. Grotzinger’s “wrap up” of the press conference, though we do have the entirety of all the four main science presentations made, including the accompanying graphics. We also have to go back and research the names of several scientists mentioned during the press conference, whose names we render here phonetically. We also have not yet been able to listen to or transcribe the highlights of the “question-and-answer” session which took place at the end of these presentations, which you can see by watching the video. We’ll try to get to that in the next couple of days. Someday, the working class of the US will see the value in having a political party of their own and will be willing to properly fund such a party, at which time we will be able to do this work full-time for the benefit of the working class. Until that glorious day dawns upon these United States, we have to continue to work other – far less important – jobs for a living! All errors of transcription are our own.
[NASA Briefing on Curiosity’s Analysis of Mars Rock – 12 March, 2013. NASA Headquarters, Washington, D.C.]
Moderator: Dwayne Brown, NASA Office of Communications
Dr. John Grunsfeld, Associate Administrator, NASA’s Science Mission Directorate
Dr. Michael Meyer: Lead Scientist, Mars Exploration Program, NASA Headquarters, Washington, DC.
Dr. John Grotzinger: Curiosity Project Scientist, California Institute of Technology (Caltech), Pasadena, California
Dr. David Blake: Principal Investigator, Curiosity’s Chemistry/Mineralogy Instrument (CheMin), NASA’s Ames Research Center, Moffett Field, California
Dr. Paul Mahaffy: Principal Investigator, Curiosity’s “Sample Analysis at Mars” (SAM) Instruments, Goddard Space Flight Center, Greenbelt, Maryland
Dr. Meyer: “The NASA Mars Exploration Program has progressively approached the red planet from a global perspective to focus exploration of regions, past and present, that exhibit the potential for life. Every successive mission has boosted our expectations that Mars could have been a ‘habitable planet’: a place that could have supported life. This program of orbiters and landers have brought us to the point of seeking a habitable environment on Mars. This is what brought the rover ‘Curiosity’ to Gale Crater. Mineralogical, and geomorphological evidence from orbit showing that the area had significant amount of water in its’ past.
“As John mentioned, on August 6th, Curiosity landed spectacularly where we wanted in Gale Crater. Within two months the team found an ancient riverbed: evidence of flowing water. And we followed that downhill to ‘Yellowknife Bay’. At the same time, we exercised the rover’s capabilities, tested the instruments for the first time, and doing science along the way. We have now completed all the ‘first-time’ activities including the first sample drilled on another planet.
“This mission has been a fantastic team effort of engineers and scientists to deliver a highly capable exploration rover to Mars. The rover is now fully commissioned for science; all the instruments are working; and the ‘keys to the rover’ have been turned over to the science team. Woo hoo! [sic – lol] [laughter]
“So, Mars has written the autobiography – its autobiography – in the rocks of Gale Crater; and we have just started deciphering that story.
“So, ‘Chapter One: Yellowknife Bay’: This was an ancient environment with the right elements (minerals indicating a near-neutral environment) and slightly salty liquid water – all the prerequisites to support life; a habitable environment. And so for the rest of the story, I’ll turn this over to John.”
Dr. Grotzinger: “Good. Thanks, Michael. It’s a great science story, as Michael was saying; and I need to start first with acknowledging our colleagues that came before us, and also the entire planetary community that supported this mission. As you know, developing MSL [Mars Science Laboratory – ed.] was a tremendous challenge and we had plenty of adventures there, but we got the support from our community and we really appreciate that.
I’d also like to thank the ‘Mars community’ and through the leadership of [Mack Donaldbeck?] and John Grant which led to the final selection of landing sites that ulimately led us to Gale, where we have had a terrific time so far – that’s been great. And also, in particular, the MER mission; ‘Spirit’ and ‘Opportunity’; ‘Mars Express’ and also ‘Mars Reconnaissance Orbiter’. ‘If we have looked farther it’s because we have stood on the shoulders of giants.’ And those missions allowed us to fine-tune our exploration campaign that led us to this place.
Finally, those of us that get to sit up here today are joined by our colleagues back at JPL [Jet Propulsion Laboratory – ed.] and elsewhere – the other P.I.’s [Principal Investigators – ed.] of the mission, including Ken [Edgett?], Ralph [Gellaert?], Don [Hassler?], Mike Malin, Igor [Mitrofanoff?] and Roger [Wiens?] and Javier [Gomelsavira?]. Every one of the instruments has led into the discovery that we have made here. Some of those instruments presented back in January when we first talked about the geology and that ChemCam discovered the first evidence for sulfates in this area here. You’ll hear more results coming out next week at LPSC [?] and then at EGU [European Geophysical Union?] over in Europe, in April, you’ll get to hear more still.
So this has been a very comprehensive exercise and we didn’t just stumble into this area; this is something that took a lot of planning.
O.K. So let me go to the first display item and bring you back to where we were the night of landing, when we as a community first looked at this slide.
Image Credit: NASA/JPL-Caltech/ASU
Location of John Klein Drill Site
“We had selected as landing site; and the landing ellipse in particular was close to Mt. Sharp, which was considered to be our primary objective. And so you can think about drilling an oil well here: you don’t just go in with one objective; you need primary objectives and you want secondary objectives. And we had a secondary objective which was a distal part of this alluvial fan that you see here in the landing ellipse. And we needed this in the back pocket in order to have the landing site confirmed by the review board, and then eventually accepted by headquarters. And in case something happened to the rover we needed to make sure we had science to do in that landing ellipse.
“But that was sort of a… you can think of it as a back-up or a secondary objective and it turns out now, in fact, that it had become our primary objective at this point.
“We landed at the… there where it says ‘Curiosity Landing Site’ and we drove just a few hundred meters in the opposite direction. We did this deliberately. And this was based on the mapping that the science team did in advance of landing, and based on the previous mapping that came from ‘Odyssey’ and ‘MRO’ and all those great missions before us. And in this particular case it led to the deliberate discovery. So it wasn’t ‘serendipity’ or ‘luck’ that got us here; it was the result of planning.
“Now, what Paul and Dave will tell you about is the part that we do consider serendipitous: we had no idea that we were gonna go into the aqueous environment that we were predicting to exist here and also find sulfates and also find clays – and those guys will tell you about it.
“So that’s one of the reasons that we’re gonna be spending some time here. So let me turn it over to Dave and he can tell you about ChemMin.”
Dr. Blake: “Well thanks, John. And, uh, you know, we got really excited when we first saw these uh… bedrock at ‘John Klein’ and saw these concretions and the reason is concretions are evidence of a water-soaked sediment – a soft sediment. But what kind of an environment was it? Was it ever habitable for life and if it was, would it preserve the organics for literally billions of years until we came here to take a look, to see if we could see what was there?
If you turn to the first graphic, you can see what made us think we really found something special.
Image Credit: NASA/JPL-Caltech/MSSS
First Curiosity Drilling Sample in the Scoop
“O.K.: well, this is what we call ‘paydirt’. This powder in the scoop here is from ‘John Klein’ – the drill powder – and it’s gray-green, meaning that it wasn’t highly oxidized. And you can see in the back of the scoop there, there’s a little bit of reddish material – this is from the ‘Rocknest’ – and this is highly oxidized. So anyway what it shows you is that this material was never highly oxidized and therefore if there was organic material present there, it could have been preserved.
The second graphic shows a comparison of the two x-ray diffraction patterns that ChemMin has collected so far.
Image Credit: NASA/JPL-Caltech/Ames
Minerals at ‘Rocknest’ and ‘John Klein’
“On the left is ‘Rocknest’ soil; and on the right is the pattern we got recently from ‘John Klein’. You can see they look very similar; and from our analyses we can tell you they both have igneous minerals – feldspar, pyroxine, olivine and magnetite. What’s different: if you look at the ‘John Klein’ diffraction pattern – down close to the central point there – the intensity is due to clay minerals. And you see they are labeled ‘Phyllosilicates’. And we can tell you from our analysis there’s between twenty and thirty percent of a phyllosilicate called ‘smectite’; and that smectite forms in the presence of water – we know that.
In addition, we have evidence of salts like halite and calcium sulfates rather than iron or magnesium sulfates that were found at Meridiani [Crater – ed.]. And this suggests that the water was a relatively neutral pH and, in other words, it was a potential habitable environment.
So all of this is what mineralogy can tell you from an ancient surface that’s billions of years old.
So the next graphic shows you what we think a good terrestrial analogue is for this material we found in ‘Yellowknife Bay’:
Image Credit: NASA/JPL-Caltech/Ames
An Earth Analog to Mars’ Yellowknife Bay
The left image shows a clay-bearing sediment deposited in a lake bed in southern Australia; and on the right you see a core of this sediment. And the different layers in the core represent different changes in mineral composition as the lake sediment was deposited. And with that, I’ll let Paul talk about what the SAM instrument found.”
Dr. Mahaffy: “Thanks, Dave. Just delighted to show you some results from SAM. And I’m gonna explain a little bit about how we did this fairly complex experiment; but I thought it would be fun to bring along what’s a full-sized scale model of SAM – the ‘Sample Analysis at Mars’ experiment.
SAM and ChemMin are both very deep inside of Curiosity, so in these kind of beautiful ‘self-portraits’ that Ken [Enge’s?] camera takes of Curiosity, you don’t see much of SAM and ChemMin. We have a test bed up at Goddard; you don’t see much of it either because it’s in an environmental chamber – it’s buried deep inside an environment that represents Mars. So here [gestures towards model of SAM sitting to his left on conference table – ed.] we’ve kind of taken away the aluminum paneling and put on plexiglass and made a model. And where the experiment starts that I’m gonna describe, we have just a little bit of sample located inside a SAM cup. And I went last night into Amy [McAdams’?] lab up at Goddard and dug around and found some nontronite, which is a clay mineral of the type that we’re gonna be talking about today. And I – there was a scale in there and I weighed out forty-five thousandths of a gram of that stuff because that’s about the amount that was in our SAM cup when we analyzed it.
So that’s where the story of this analysis that I’m gonna tell you starts; [begins demonstration, approximately 14:28 in the video – ed.] we have the sample in the cup in SAM – we have loaded it the previous ‘Sol’ (the previous day) – and we’re ready to do our analysis.
So, it’s night on Mars – the rover’s ‘gone to sleep’. SAM’s kind of a night owl – we like to operate at night and – nobody else there to bother us – but’s it’s also a good thermal environment for some of the intstruments to operate.
And so, we had put the sample in the cup, through this little inlet tube – this vibrates as the sample’s going into the cup. And then the sample manipulation system developed by our collaborators at Honeybee Robotics is, uh… can be seen down here. And it turns out that the way the sample gets to the oven is: this little carousel rotates; the sample is dropped into the cup; the oven… the [corret?] cup moves over; and then it raises into
the oven – a very small oven where we take the sample up to the maximum temperature that I’ll show you.
And what we do then is that we start heating up the oven; we get a flow of helium going over the sample; we heat up the oven and then with the mass spectrometer (which is right in this area) we sniff a little bit of that gas and we measure the chemical constituents that come off. And as we do that we capture a little bit of gas in our tuneable laser spectrometer that was developed by Chris Webster’s team out at JPL; and we capture a little bit more of the gas in a ‘hydrocarbon trap’ because one of our objectives of this experiment really is to search for organic compounds on Mars. And we, later, will send this gas to the gas chromatograph… I think I have a button here that will make one of the columns light up… and then the gas goes through those columns and the individual constituents come out one-by-one and then back into the mass spectrometer through a back door, and again we analyze what Mars is made of.
And so, if you go to the first graphic, we’ll show you some of the data.
Image Credit: NASA/JPL-Caltech/GSFC
Major Gases Released from Drilled Samples of the “John Klein” Rock
“And this really is just picking out the five major gases that were evolved from the sample. And let’s start with what’s labeled ‘Water’ on top… but the mass that we’re monitoring – that is ‘mass 18’ (that’s the signature of water). And you see the temperature scale on the bottom (going all the way up to fifteen hundred degrees Fahrenheit in this case). And that water is coming off at really high temperature. And that’s exactly characteristic of the smectite clays and it’s very good confirmation of what the ChemMin saw – we really do have clays here; and about thirty percent of the water that’s coming off is that… is that high-temperature water.
Go down to the lower left: you’ll see a blue trace; that’s oxygen. We’ve blown it up by about a factor of ten in this case for illustration. And we did see some oxygen at our ‘Rocknest’ dust pile; and we attribute that to the decomposition of a perchlorate, which is pretty interesting. It looks like there’s very likely some perchlorate here as well.
The red peak is, likewise, carbon dioxide. The carbon dioxide is produced either from oxygen reacting with carbon in the sample and making this carbon dioxide, or really the other alternative is the decomposition of carbonate. And both of those possibilities are just fascinating, so that’s what we’ll be pursuing as we progress with new samples and so on.
And then, finally, in the bottom right, at higher temperatures, you see masses labeled ’64’ and ’34’. And those represent an oxidized and a reduced form of sulphur; they represent, respectively, sulphur dioxide and hydrogen sulphide. And so, that’s just fascinating: we have both oxidized and – much more than in this atmospheric dust – much more reduced sulphur there as well.
What the tuneable laser spectrometer was doing in the meantime in this experiment was measuring the deuterium-to-hydrogen ratio in water. And it… very interesting observation. We had measured very high deuterium-to-hydrogen ratio in water evolved from the dust; and we understand that as being a signature of a good fraction of water having been lost from the Mars atmosphere over geological time. And in this sample we see just the lowest deuterium-to-hydrogen ratio that we’ve seen in evolved gas so far; and so that’s something that we’re gonna definitely be pursuing as we go forward with other samples.
So go to the next slide. And here’s what the search for organics is looking like.
Image Credit: NASA/JPL-Caltech
Chlorinated Forms of Methane at “John Klein” Site
The data looks like… uh… signatures of mass-to-charge, just as I showed in the previous time; but here these compounds are coming out of the end of the gas chromatograph column. And here we see two compounds that we actually had also detected at ‘Rocknest’: very simple chloromethane and dichloromethane compounds. And it looks like they’re above the background level; it looks like they’re there.
Uh, we have to be very careful at this point in interpretation. This was the very first sample that had gone through the Curiosity drill; and so there’s always the possibility that some residual carbon that was on the drill bit made its way into this sample. So we’re really looking forward to repeating this experiment and seeing if these signatures of simple chloromethane compounds persist.
So, the really good news is the instrument is just working beautifully; it’s a credit to the very talented team that worked hard on not only making this stuff but making it robust and making it work in this very difficult environment on Mars.
So, with that I’ll turn it back to John for some additional comments.”
Dr. Grotzinger: “Great. Thanks, Paul. So, what I’d like to do now is sort of set the stage a little bit for what we view in this mission as the transition from the original goal, a decade ago, from the search for water on Mars to, now, the search for habitable environments on Mars. And if we go to the first display item there…
Image Credit: NASA/JPL-Caltech/Cornell/MSSS
Two Different Aqueous Environments
“…what we can see are two rocks separated by a decade of research: the one on the left is from the ‘Opportunity’ rover back in 2004 (a rock called “Wotney”). And what you see here is a rock – these images have been processed by Mike Malin and Jim Bell with what’s called ‘white balance’ – and it helps bring out our terrestrial intuition to sort of get a sense of what these rocks would look like if they were on Earth. The one on the left is basically from the sequence of rocks at Meridiani Planum: a rock that is reasonably fine-grained; the particles were either formed in water or transported in water; it was then cemented in water (converted from sediment into rock); and then after that it was fractured and then some of the fractures were filled in with what looks like a relatively thin material (in this particular rock) but then you see all the bumps sticking out. Those are the famous ‘blueberries’; these things we know are concretions.
“Well it turns out these things are turning up on Mars; and here on the right is our rock in the ‘Yellowknife Bay’ area called ‘Sheepbed’… uh, unit, we’ve named it. And again you can see it approximately has the same color on the surface; it’s laced with these features that look like concretions to us; and the big difference is, is that you can see in that rock that it has a white veinfill running through it. That’s the thing that ChemCam first hit; and told us that there were probably sulfates here. So texturally, you see rocks that were transported in water, formed in water, cemented in water, altered in water and, uh… but that’s what you get on the surface. And so what we need to do is scratch below the surface and if you go to the next one…
Image Credit: NASA/JPL-Caltech/Cornell/MSSS
Studying Habitability in Ancient Martian Environments
“…uh… this is what a decade of engineering gives you. On the left, there’s a rock that was one of the first rocks that we ever interacted with at Meridiani with the RAT (Rock Abrasion Tool); and on the right we have the drill hole from Curiosity. And the drill hole’s about one third of the size of the RAT hole there on the left.
“But the big story is in the powder that’s generated. And so, as we learned at Meridiani, we have a rock that is composed significantly of hematite in addition to the sulfates – iron-bearing sulfates – that indicate very acidic waters. On the right, we get to see the ‘new Mars’: the gray Mars, that one that suggests habitability, that has these clays and other minerals present.
“So what, then, do we mean by habitability? The key thing here is an environment that a microbe could have lived in – and maybe even prospered in. So there’s three things that we want to point out today that Dave and Paul have shown you. And the first issue comes down to acidity. We don’t see any of the evidence that we have here – the rock on the left; the one from Meridiani? It’s totally different in the subsurface in this rock on the right: we have the clay minerals (which form in neutral pH); we don’t see the iron sulfates (which indicate acid pH); instead we see calcium sulfate. This rock, quite frankly, looks like a typical thing that we would get on Earth. And it’s a neutral pH environment; and I think everybody has a sense of what ‘acidity’ means, but… there are some microbes that exist at very, very low pH’s… ‘but wait, there’s more!’
“And the second point is water activity: this is ‘how much available water there was for a microorganism to live in its environment?’ So with that, I’m gonna pull out a prop here [produces familiar plastic ‘Teddy Bear” container of honey – ed.]: it’s a jar of honey. Everybody always wonders why it is that a solution of water and sugar can last on the shelf for ever and ever without spoiling. And the reason why is that even though there’s a lot of water in this honey, there’s not enough that’s available for a microorganism. And if a microorganism ends up in here, all the water will be sucked out of the cell – it’s this thing called ‘osmosis’ – and the organism won’t be able to live.
Turns out, the rock on the left there? That’s what we think happened at Meridiani, but instead of sugar we had a salt called ‘magnesium sulfate’. And there was so much of it that it would have inhibited microorganism[s] that lived there. That was not a habitable environment.
And then there’s one more thing that we’re really excited about that we found at Meridiani – sorry; at Gale: and, uh… it’s a battery [holds up a typical dry cell battery – ed.]. And basically these minerals that Dave and Paul were telling you about – they’re effectively like batteries. Some of them are negatively charged and they have various oxidation states; and what we have learned in the last twenty years of modern microbiology is that, very primitive organisms, they can derive energy just by feeding on rocks. So when Paul talks about ‘sulfate versus sulfide’ and Dave talks about clays and magnetite, these are the kind of things that tell you that there could have been a flow of electrons in the environment, just like on this battery: you hook up the wires and it goes to the light bulb and the light bulb turns on… that’s kinda what a microorganism wouldv’e done in this environment if life had ever evolved on Mars and if it was present here.
So that’s what we mean by ‘habitability’: you take all three of those factors… and to really understand that, that’s what we built this payload for, and that’s what we feel that we have succeeded at.
[Question and answer session]
Q: “NBC in Los Angeles. Can you talk to me a little bit about the area where the rock was found? What would it have been like in ancient times? What would we have seen there?
A: [Dr. Grotzinger]: OK… so, what we imagined it would have looked like was the picture that Dave showed [“An Earth Analog to Mars’ Yellowknife Bay”, above] we feel is a pretty good representation. It’s conservative in the sense that it shows a lakebed that’s dry; the lakebed was filled by sediment that’s derived from streams… but we don’t know how long-lived it was; and so that’s always a challenge we’ve got on Mars. It’s not like the rocks come with numbers on them that tell you how long the water was there, or how much there was there, ultimately. But we believe that we wound up in this ‘Sheepbed’ unit at a place that was wet for a relatively long period of time – enough for all these chemical reactions to occur.
Q: “Irene” from Reuters: “Congratulations! This is pretty exciting stuff you guys are reporting today. I have two questions: first is ‘What else needs to be done for analysis of the organics to… you mentioned a little bit about “the assessments were preliminary”; and the second question probably is for John: I know this is not a ‘life detection’ mission but given that you’ve scored a ‘hole-in-one’ so early, how much farther can you push this through the remaining eighteen months of the primary mission?”
A: [Dr. Grotzinger]: I guess, Irene, the answer to the second half of the question is to underscore what you said, which is that we’re not a ‘life detection’ mission; if there was microbial metabolism going on, we really wouldn’t have the ability to measure that. And if there were ancient microfossils in the rock, as good as MAHLI [Mars Hand Lens Imager – ed.] is… I mean it can tell us definitively that ‘we have a mudstone here’ but it would not be able to resolve individual fossil microbes.
What we can do is to survey additional targets that we have picked out; and we still want to go to Mt. Sharp and we hope to get there. And there are different combinations of minerals that we see fron orbit that give us different prospects, and what I hope will become a burgeoning new field of ‘comparative planetary habitability’. And what that means is that if you look at how we’ve studied the ancient Earth, and you look at the minerals and compounds and substances that are available, and you look at the ways that different prokaryotic microorganisms can do their metabolism… they use different materials; it’s almost like an organism has evolved to exploit every one of these little ‘rock batteries’ that exist in the record. And so the question is: how many of these different kinds of ‘batteries’ can we find at Gale Crater? And I think that really becomes our mission, along with the search for organic compounds.”
A: [Dr. Meyer (in response to follow-up question)]: “[…] And as you mentioned, solar conjunction…we’re headed toward that. Basically, we can’t talk to the rover and the rover talk to us for most of the month of April. And so, what’s gonna happen is we’ll do some more science activities now – through the end of this month – permitting, with the engineers, confirming that things are safe for us to do those operations, but we will not do another drilling – the second drill hole – until after solar conjunction. So that… we’re not gonna start that activity until May.”
Moderator: “Our next caller, from the Wall St. Journal, Robert Lee [Huntz?].
Q: ” […] So, gentlemen: in a simple, straightforward declarative sentence… or two, please tell my readers what you have found here and why it is significant.”
A: [general laughter] Dr. Grotzinger: “I can take a… I’ll take a swipe at that. I think we had a … we have found a habitable environment that is so benign and supportive of life that, probably, if this water was around and you had been on the planet, you would have been able to drink it.”
[Long pause – ed.]
Moderator: “I think that did it for him.”
Moderator: “[…] let me take another question from Twitter: ‘The Opportunity rover: ‘three months’ and it’s going on for many, many years. How long do you think Curiosity could last?’ ”
A: Dr. Meyer: “The half-life of its power is on the order of 84 years. So I expect the rover to be there to shake the first astronaut’s hand… if the astronaut goes to Gale Crater.” [laughter]
Moderator: “Next up: New York Times… Kenneth Chang. Ken?”
Q: “[…] I was wondering… given that [these rocks?] had good preservation, was there hope or expectation that they actually would have a stronger organic signal? And what does it mean that you don’t have a stronger signal?”
A: Dr. Mahaffy: […]
A: Dr. Grotzinger: “Kenneth, if I can I’ll just add a little bit to that. Paul’s reference to the early Earth is… you know in our history of exploration there… you have to have a search paradigm. And that paradigm gets built on your understanding of the processes that result in the preservation of organics in the rock record. And one of the big things on Earth is that because of plate techtonics we have a lot of heat that exists… that, of course, exists today. So, a lot of organic compounds are degraded in the presence of that heat.
“On Mars, we actually think the planet cools with time, and so it may not be that heat’s the problem, it may be that radiation is the problem – something that we’re not so affected by on Earth. So we have these three factors, as I said before. To reiterate them (I think we’re all gonna have to learn these): the first is the primary concentration mechanism; the second is that all that ‘cool chemistry’ that creates the habitable environment – including the presence of water itself – is not necessarily a good thing for the preservation of organics. And then the third thing is the radiation environment. And so our ‘trick’ is to find a place where all three of those things ‘went right’ – and that could take the entire length of this mission… but we’re gonna give it our best.”
Q: Dr. Jim Green, Director, Planetary Systems Division SMD: “The one question I have, then: based on the observations, uh… what you’ve found out today is, would you say that Mars was habitable before or about the same time as Earth was in the history of the Solar System?”
A: [general chuckling on the panel] Dr. Grotzinger: “That’s a good question, Jim.” [laughter] “I’m not sure we’ll ever really be able to address that with our payload but, uh… you know, we’ve got a couple of different options here for the age of… of… just relative to Mars, how old these things are. And right now, quite frankly, they go between being as ‘young’ as that alluvial fan lobe that comes down – which I think would be relatively young in the history of Mars – and it could be quite old. Maybe these rocks are somehow related to the base of Mt. Sharp. We can’t rule out that we’re looking at the base of Mt. Sharp right now – in a way? So we’ve got a lot of options open before us… but I think, in any one of those versions, we’re talking about older than three billion years ago; and we’re probably looking at a situation where – plus or minus a couple hundred million years – it’s about the time that we start seeing the first record of life preserved on Earth. It’s a great comparative planetary question.”
Q: Craig [Kovalt?] [Space Rep/ Curious Mars?]: “The question on the clays: it’s one of the more significant findings is that you [had?] abundant water flow through the clay. Uh… how does that relate to meteorite findings where they had also identified significant water [unintelligible] clays found in Martian meteorites? […]”
A: Dr. Blake: “Well, I think… you know, the clays in Martian meteorites were just… almost trace quantities and… probably… and the Martian meteorites that we’ve seen are mostly purely igneous rocks. The clays in this rock – which is a mudstone (which was something deposited in a shallow aqueous environment) – are really a major percentage of the rock; and so they really represent a significant process. Plus… I guess you could call meteorites the ultimate – what we call ‘float rock’: it came from someplace else and we don’t know where it came from. We know where theis stuff came from: it came from this bedrock in Yellowknife Bay, and so we know that this environment existed in Yellowknife Bay with plenty of water.”
[To be Continued – IWPCHI]