|The Mars Society|
Who & Where
Education & Outreach
Margarita Marinova (MM): Good evening everyone. I would like to welcome you to the first public lecture by the Toronto Mars Society Chapter. The Mars Society was founded last August in Boulder, Colorado, and it was done by a conference. It had about seven hundred people, one hundred and eighty lectures were presented at that talk and it did show the great enthusiasm that there was about Mars, exploring the planet, learning more about it and also human settlement. The main purpose of the Mars Society is to further the exploration of Mars and also to settle the planet. The exploration is going to be done both privately and by government funded missions. We believe also that there has to be private incentives to get the government going further. The major project right now for the Mars Society is building a base in the Canadian Arctic. It is going to be in Haughton crater on Devon Island. And this is because the Canadian Arctic is very good for simulating a lot of the features climatically and geologically that would be found on Mars. And it would be sort of a step in learning what it would be like to send humans to Mars and explore the planet. For the Toronto Mars Society Chapter our main goal is to do outreach and to show people that it is possible to go to Mars with today's technology and also at a reasonable cost. So we will be doing a lot of that at all ages and all stages, also we want Canada to be more involved in Mars missions, so that when people do go to Mars we have a Canadian on the team. And we want Canada to get involved in the Arctic Base.
Our speaker tonight is going to be Chris McKay. He is from NASA Ames Research Center. He is at the Space Science division. Doctor Christopher McKay got his Ph.D. in Boulder, Colorado in 1982 in Astro-Geophysics. Since then he has been working at NASA Ames Research Center on Planetary Sciences. In '81 he won the United States Antarctic service medal and in '87 he won the Uri prize of the division of Planetary Sciences. In '91 the Arthur S. Fleming award which is awarded to only ten [U.S.--Ed.] government employees. In '94 the NASA Ames Associate Fellowship award and also the [unheard] Memorial Award. He has been doing a lot of work in Antarctica and the Arctic and Siberia and also desert environments. And this is basically to study how life survives and develops in these extreme environments. So I would like to present to you Doctor Chris McKay.
Chris McKay (CM): Thanks Margarita, itís a pleasure to be here. I am going to try just speaking because the acoustics in this room are pretty good. And if I put my mic' on I'll trip over it, fall off the stage - it will be embarrassing for all of us. It's safer this way.
Well what I want to talk about tonight is the prospect of sending, bringing life to Mars. Tomorrow in the Geology department I'll give a seminar about searching for evidence of past life, looking backwards in Mars' history. Tonight I want to look to the future of Mars' history. And first let me - I am from NASA, I have to show a NASA-style view graph chart we all can show. And I am showing this for a reason: NASA is starting a program, which is called "astrobiology". And astrobiology is got in the announcement that Headquarters put out they listed six questions. That they were calling for proposals to address those six questions. And the first five questions were the same old hat. Things we've been doing, not that they weren't good. Its good that we're doing these things, habitable worlds, living systems, the origin of life, recognizing other biospheres, understand the history of the Earth, understanding the effect of humans on the Earth in short time scales. Those five questions were ongoing programs within the agency. The things we have been doing for decades. Good things and they are exciting things. And I am glad we are doing them.
How are we approaching that and what does it mean? What I would like to do is keep it informal. If people have questions or derogatory comments or editorial that they want to insert let's just do it in real-time and keep things informal. I am going to have to give a little background on what we know about Mars and it's history.
We always thought that Mars was the planet that was most likely to give us information about life and which is why in '76, years ago Viking landed on Mars to search for life. It had a robotic arm it took some dirt did some simple biology experiments and basically found that the surface is dead, "Its dead Jim!" was the main result from Viking. Why is Mars dead?
It's a compelling story and I think itís the story thatís going to take humans to Mars. I think thatís the scientific story thatís going to be the attractor thatís going to bring scientists, humans to Mars that are going out and study, study the planet. And then that leads to where does it go from there? Humans go to Mars for a variety of reasons, they will probably set up fairly self sufficient bases getting their resources of air, water and food from the environment. And it's logical to ask what does that lead to in the future. So this is this is up to now everything has been in a sense an introduction. Now we get to the heart of the matter what is the future for Mars. I have been saying that Mars is a planet with a past, a very interesting past, maybe a biological past. We have some understanding of how it might have got to the cold dry state that we see today. And the question is, could we bring back the warm environment that it had in the past. Could we do CPR on this dead planet, just recently dead planet, only three billion years. Does Mars have a future? Well thatís what I want to talk about tonight. Could we bring Mars back to life or could we bring life there. Let me put in a short footnote here. Even though it would be great to think that there is life still on Mars in a dormant or sub-surface form. But unfortunately an objective look at the facts leads me and many others to think that there is nothing alive on Mars today. Nowhere on the surface and nowhere on the sub-surface. For a variety of reasons most of which trace back to radiation killing any dormant stages over billions of years. So unfortunately we think Mars is lifeless. So what we are contemplating is the notion of bringing this lifeless world back to life, sharing with it the genome from Earth.
Questioner (Q): Sir, does that include also bacterial life?
CM: Including bacterial life.
Q: Why are they worried about the contamination issue then? Bringing samples back to Earth?
CM: Because we are not sure that it's dead. The question is if we think Mars is lifeless why do we worry about bringing a sample back to contaminate the Earth with Martian life, if we think it's lifeless. And itís the difference between thinking something is true and haven proven that it's true. The difference between a logical certainty and a demonstrated fact. We think that Mars is lifeless, that is not a demonstrated fact. And bringing a sampleÖ
Q: But that coupled with previous experiments that sampled the ground in surrounding areas, because, same thing right?Ö
CM: Well previous missions we haven't brought any thing back. We have only investigated Mars. The vehicles that went there were sterilized so that we wouldn't get a false positive from an Earth organism. But brining samples back we will keep them in containment. Well how do we, what is the fundamental reason we think this is possible. I would say there is two reasons. One we can look back at the past and see that Mars had a habitable state years ago. We don't have to imagine something completely out of whole cloth to make it habitable once more. And secondly when we look at Mars we realize that the fundamental challenge to make it habitable is to make it warmer and we know how to warm up planets, we are doing it on Earth. Its probably not a good idea to be doing it here on Earth, but we know how to do it. We can point to what we are doing on Earth and say, hmmm I wonder what that would do if we did it on Mars. Now I'm talking about Mars and you can say what about other planets besides Mars. And I think the simple back of the envelope calculation shows none of the other worlds are even close to being habitable. None of them. None of the others can be made, this is Venus. Trying to spin up Venus it's ridiculous. Human, human civilization does not have the technology to alter any of the physical properties of the planets. We can alter the climate of planets and then only in certain cases. And Mars happens to be one of those cases. Mars is just within the capabilities that we have. None of the other planets come close. Question there.
Q: What about Europa?
CM: Europa is one of those planets that could have water, could have life. But making it habitable for Earth like life and any resemblance to the Earth is just beyond out technology. Itís the surface temperatures of Europa is something like minus 100 centigrade and it's got no atmosphere. So it's hard to imagine it as an Earth like planet in any stretch of the imagination. Titan probably after Mars is the best candidate. But even that the temperature on Titan is 95 Kelvin right now, minus 180 something centigrade. It's very cold and if you calculate just how much energy is required to warm it up you have to postulate something like cold fusion actually working not just cold fusion but cold fusion working and then you can imagine Titan warm enough. So all the other planets are way beyond our technological capability, you have to get into antimatter and what not. So Mars is the candidate. Question here.
Q: Do you have an idea, the way you are proposing to heat it is to trap heat that is coming from the sun right?
CM: Well you haven't seen how I am proposing, thatís five or six slides down. You have to bear with me.
Q: OK, OK.
CM: I didn't want to - OK. Let me get to that, because I give a lot of information on how we're how I propose to heat it up. But first let me talk. Before I talk about how to heat it up we have to define where we want to be. What does it mean to be made habitable? We imagine warming up Mars, making it look like this, what does that really mean? And it's important to keep in mind that even looking at the Earth we realize that there is two distinctly different habitable that the Earth has experienced in time.
Q: There are two questions, the first question I was going to ask earlier. Mars if I remember correctly is at two eightyÖ
CM: One point five.
Q: One point five.
Q: So you have about a third the size.
CM: Half the size.
Q: Half the size and you have it would take a little longer to heat up than Earth. The other question is how do you prevent it from going past that?
CM: Good question. The first question is, Mars is one and a half times further from the sun and so it does get less sunlight. You can calculate how long it would take if you introduce these gases for Mars to warm up if it had an efficiency of trapping solar energy of about ten percent is what we would expect for these kind of processes. The answer is about fifty to one hundred years. So it's not a real long time. It's not astronomically long. And it's the second question is could once you started this process of warming where would it stop? And the answer is it wouldn't stop until all the CO2 came out, out of the soil and regolith. So you can't it's like opening the floodgates it's just what ever is there comes out. You warm up the planet and all the CO2 will come out. How much is there is the key question. We don't know yet the answer. The current estimates is that there is only probably about one hundred to two hundred millibars of CO2 exchangeable in the polar regolith or in the polar caps. Which would not warm Mars completely to Earth like conditions. It would warm it sort of Antarctic-like conditions. Which are pretty comfortable actually compared to present Mars. Minus twenty is a good deal warmer than minus sixty. You probably get minus 20 here occasionally, if you got minus sixty you would all move to Florida or something. So minus twenty would be a good step forward. So it's unlikely we would be in a situation where it would become too warm. Where there is two bars of CO2 and it would come out with three bars or a Venus like state. But we don't know that and so certainly one key question is to determine the total inventory of CO2. Question here.
Q: Yes how long do these gases last?
CM: These gases, the criteria you would pick for which gases for which gases you would use to warm Mars. Could be first the elements that you make the gases out of would be available on the surface. To make the stuff there. Sulfur, fluorine, carbon are all available. Nitrogen is not readily available and hydrogen is relatively hard to get to. So sulfur, chlorine and fluorine are the molecules you put together. The second criteria is that they be good, very good greenhouse absorbers. And the third criteria be that they have long life times in the atmosphere. That the bonds that hold the molecules together are strong bonds. So that they can resist UV radiation and for example C, carbon tetrachloride has an estimated lifetime of about five hundred years in the Mars atmosphere. So as long as you are trying to maintain a warming you have to make them fast enough to replenish them over a five hundred year time scale. Now if enough CO2came out of the polar cap and the ground then you could stop making them and Mars would stay warm with that thick CO2 atmosphere. But if you lower the CO2 down to the levels that would be breathable by humans then Mars would be too cold unless you resumed making those gases. So a oxygen atmosphere is not warm enough because Mars is further from the sun and must be supplanted, supplemented either by super greenhouse gases or by CO2 levels that are above the toxic level. Question.
Q: Mars' atmosphere is about one hundred kilometers?
CM: What the thickness?
CM: Well it depends on how you define thickness. If you were to take the Martian atmosphere and compress it into a layer at the same density as the current surface it would make a layer about ten kilometers thick.
Q: I suppose to the limit where it loses quite a bit to space, if you added some of those super gases would some of those escape the envelope of the atmosphere?
CM: No, not really. No the point the top of the atmosphere you define the top of the atmosphere as the point where the mean free path is long enough that a particle can be on an escape trajectory. The exophase as it is called. That is still very high and as the atmosphere went up in pressure that base would just move. The whole atmosphere would just move up to a pressure level and it would move up as well to a higher level. Question.
Q: Is the mechanism by which Mars first lost its original atmosphere still in place?
CM: Yes. Thatís a good point. You imagine here to Mars and bringing it to a state was eventually it will run downhill again. We estimate that it took about one hundred million years for Mars to run downhill. So a hundred million years is a long time. It's a good thing to spread mortgage payments out over one hundred million years. But an interesting point to think about is that the Earth isn't going to last much longer than that. If we were to bring Mars back to like we would have say one hundred million years life expectancy. The life expectancy of the Earth from now looking forwards is not much longer than that. The upper limit of the life expectancy of Earth is only forty times longer than that. Forty times one hundred million being four billion years when the sun goes red giant. So as a factor forty at most, likely the Earth will become Venus like much sooner. May be as soon as a billion years due to the brightening of the sun. The sun is getting brighter with age as we do. Maybe some of us do. And the Earth will have a runaway greenhouse in typically a billion years. Thatís only ten times longer than the life expectancy on Mars. So one of the lessons here is nothing lasts forever and it's just a question of relative scale as to how long it lasts. And one hundred million years is in the right ballpark. Question.
CM: Well that's a good question. Let me turn to the second part of the talk, which is, which I want to call ethical issues. It is particularly appropriate to talk about that here because I first started getting interested and working seriously on it with Bob Haynes. The late Bob Haynes who was at York University. In fact my previous trip to Toronto was to visit Bob Haynes. And this is Calvin my colleague, Calvin and it points that there are other issues as you were saying. The other issues besides just, Can we make Mars habitable?Continued...
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