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00:00when it's time to move to another planet Mars is right next door but it's a
00:08freeze-dried rock too cold for life we could warm it up but not like this well
00:17we know how to warm up planets we're demonstrating that we know how to do
00:20that right here on earth where it's probably not a good idea we'll do it the
00:24old-fashioned way with factories and global warming on purpose in a hundred
00:32years Mars will be warm wet and ready for life it's called terraforming and it
00:39sounds like science fiction but it may be coming to a planet near you sooner than
00:45you think that's not something for 500 years in the future that's us we're
00:52going to Mars
01:07what would it take to make water flow on a world where the average temperature is
01:1380 below 0 or turn bare rock and dust into soil where forests could grow what
01:27would it take to terraform Mars create a planet more like Earth where humans
01:33could breathe the air it would cost billions and take hundreds if not
01:42thousands of years to accomplish
01:48but transforming Mars from a barren rock into a living world is not as far-fetched
01:54as it may seem and our long-term survival could depend on it if you're a
02:02threatened species which let's face it we are you don't want to all be in one
02:06small habitat you want to be diversified
02:12terraforming is already on its way from science fiction to science fact here on an
02:18eighteen thousand five hundred foot volcano in Mexico called Orizaba
02:24it's a magnet for climbers adrenaline junkies and planetary scientists
02:33Chris McKay is one of them an astrobiologist interested in the
02:42possibility of life on other planets his research takes him to extreme
02:49environments all over the world places that expose the limits of life on earth
02:55what draws him to Orizaba are the trees and in particular the tree line at 13,000
03:08feet it's among the highest in the world which means these pine trees live right at
03:13the edge of what trees can tolerate we're trying to understand what is it that sets
03:19the tree line we want to know why do the trees go down there but not here clearly
03:25it's warmer down there and temperatures the key variable but something in the
03:29forest ecosystem is responding to temperature McKay and colleagues from the
03:34National University of Mexico have been experimenting with seedlings above the
03:39tree line following their progress over time that's 152 it's basic environmental
03:46research to understand how the ecosystem works but for McKay there's another
03:51motive with implications far beyond this mountain and even this planet
03:58he hopes that discovering the minimum requirements for trees on earth will get
04:04him closer to understanding what it would take to grow trees on Mars at the
04:12moment Mars looks like a bad place to grow anything 50 million miles farther
04:18from the Sun than earth it's a frozen desert of rock ice and dust and it's been
04:25that way for billions of years it's little more than half the size of earth but it
04:33has the same land area as all the continents on earth combined
04:39intense ultraviolet and cosmic radiation sterilized the surface temperatures can
04:47range from 200 below zero at the poles to 80 above near the equator but the
04:55carbon dioxide atmosphere is so thin when ice thaws it turns straight into vapor not
05:01liquid leaving the surface bone-dry
05:10to bring this hostile world to life would take planetary engineering on an
05:15almost inconceivable scale but McKay believes the potential is there waiting to
05:23be tapped
05:28and the Orizaba volcano is a kind of living laboratory for understanding how it might
05:34happen conditions on Mars are like the top of a very high mountain imagine a
05:42mountain on earth 100,000 feet high that's what it would be like on Mars very low
05:47pressure very low temperature high radiation conditions so harsh and no
05:52life form on earth could survive
05:54there are no 100,000 foot peaks on earth but the 18,500 foot summit of Orizaba is a
06:06polar desert like Mars with a very thin atmosphere and temperatures close to zero
06:12but at lower elevations the temperature rises as the atmosphere thickens
06:20bare rock gives way to grassy tundra and the first signs of life on the surface
06:29then abruptly the tundra gives way to trees a dramatically more diverse ecosystem
06:44this transition from a barren summit to an alpine forest is the same sequence of
06:51change that Mars would go through in the process of terraforming so the tree line is
06:57the key we want to understand that transition we want to know how much do
07:02you have to push Mars how warm you have to make it before the first forest before
07:07the first trees can grow on Mars terraforming has been a special passion of
07:15McKay's throughout a long career as a researcher and scientist on planetary
07:20missions
07:24began with the realization that Mars was not always as hostile to life as it is
07:29today
07:32orbiters have found dried-up lake beds river channels and deltas all over the
07:37planet
07:39clues to an early Mars that was a warmer wetter place than it is today
07:46the rover spirit and opportunity have found rocks and minerals that could only
07:51have formed in the presence of water
07:57that means Mars must once have had an atmosphere dense enough to trap the heat
08:01of the Sun like a greenhouse and create enough atmospheric pressure to keep liquid
08:07water stable at the surface conditions that could have been suitable for life
08:12this was more than three and a half billion years ago when the solar system was young Mars was still
08:23hot inside and volcanoes pumped carbon dioxide into the atmosphere comets and asteroids pummeled the
08:33surface heating and thickening the atmosphere even more
08:37closer to the Sun Venus and Earth started out the same way but only Earth remains
08:47habitable today
08:52as the Earth cooled rain washed much of the carbon dioxide out of the atmosphere
09:02dissolving it in the oceans where it combined with other elements to form carbonate rocks on the seafloor
09:09today most of Earth's carbon is locked up in these rocks very slowly they're pulled
09:17back into the hot interior as the seafloor slides under continental plates at the
09:25boundary they sometimes melt and erupt through volcanoes at the surface releasing
09:30a slow but steady stream of co2 back into the atmosphere producing enough
09:35greenhouse effect to keep the planet warm but not too warm
09:44as life evolved it continued to transform the atmosphere for its own benefit
09:49adding a mix of oxygen and nitrogen suitable for life
09:58this delicate balancing act of biology and geology
10:02sustains our biosphere today
10:07Venus wasn't so lucky
10:10closer to the Sun it turned into a runaway greenhouse
10:17its early oceans boiled away leaving a world so hot and dry
10:22visiting spacecraft have lasted only a few minutes on the surface
10:28Venus today is like an earth that's been baked dry
10:32very much like the earth in many respects but it's got a hundred thousand times less water
10:37it's very very hot it's 900 degrees and very high pressure almost pure co2 atmosphere
10:43so it's like your worst nightmare of the greenhouse effect
10:50Mars went to the other extreme not a runaway greenhouse but a runaway ice house
10:57only one-tenth the mass of earth it cooled off quickly the volcanoes died out and its once thick atmosphere
11:05gradually disappeared
11:09with almost no greenhouse gas to trap the heat of the Sun create pressure and block radiation
11:15Mars turned into the sterile freeze-dried world it is today
11:20Mars is almost ten times smaller than the earth and as a result
11:24it has no plate tectonics to recycle sediments
11:28it has no magnetic field to protect it from the solar wind
11:31and it has less gravity to hold its atmosphere
11:35all of those factors cause Mars to lose its atmosphere become cold and freeze up
11:41but remnants of the early atmosphere may still be there
11:45buried frozen or bound up in the soil
11:49and figuring out how to get them back is McKay's goal
11:53think of it as a thought experiment
11:55there's a world out there we have evidence that it once had water
11:59once had habitable conditions it may have had life
12:02could we imagine bringing it back to life
12:05is that within the scope of our understanding of planetary science
12:10and the technologies that we humans can deploy
12:17to terraform Mars we'll need to rebuild its early greenhouse atmosphere
12:21and that will require carbon dioxide and water
12:25there's some carbon dioxide frozen at the poles as dry ice
12:31and more saturating the ground like water in a sponge
12:35the gas releases in the summer months
12:40thickening the atmosphere by 30%
12:42and then condenses back to the ground when it turns cold again
12:47that accounts for some of the original CO2 atmosphere
12:52but there should be more
13:00scientists have long suspected that much of the early CO2
13:03reacted with elements in the ground to form carbonate minerals
13:07the rover's spirit and opportunity have instruments specifically designed to see carbonates
13:16but so far they haven't found them
13:20we don't know what happened to the initial carbon dioxide atmosphere of Mars
13:25it is possible that it's gone forever
13:28and that would be bad news for the notion of making Mars habitable
13:31it's also possible that it's hidden in places that we don't see
13:35after all we've only dug down below the surface a few inches
13:39it would be premature to think that we know everything that's going on about Mars
13:44but it's a mystery and it's certainly one of the key questions that needs to be answered
13:49in terms of can Mars be restored to habitability
13:52is there enough carbon dioxide available to make a thick atmosphere
13:58if the answer is yes then we've got a plan
14:02if the answer is no then that's a serious problem
14:05and it pushes off restoring Mars to habitability
14:08to some future technology that we don't understand yet
14:11still, McKay is optimistic about the carbon dioxide
14:15and he's even more confident that there's plenty of water on Mars
14:19in the form of ice
14:21in 2002 an orbiter detected vast reservoirs of hydrogen
14:26shown in blue here
14:29it's the H in frozen H2O
14:33in 2008 the Phoenix lander touched it for the first time
14:39water ice just inches beneath the surface
14:44and recently the Mars reconnaissance orbiter found even more
14:49a glacier under a layer of dust closer to the equator
14:56it may be one of many on Mars
15:00when we look at Mars today
15:02we see all the elements needed for life
15:04and everything we've learned about Mars suggests that
15:07recreating the habitable conditions it once had may be possible
15:12vital elements of the early atmosphere may still be on the planet
15:18but immobilized by the extreme cold
15:23to terraform Mars
15:25we'll have to bring them back to life again
15:27after three and a half billion years
15:30in the deep freeze
15:42Mars is a dry frozen world today
15:49but colonists from Earth will someday be looking for ways
15:52to make it more like home
15:55the first and most important step in making Mars habitable
15:58is to warm it up
16:00the fundamental problem with Mars today is it's too cold
16:05we'll have to warm Mars from its average of 80 below zero
16:09to about 25 below
16:11to get terraforming started in the warmest regions near the equator
16:15and it would take something pretty dramatic to generate that kind of heat
16:22one person who has pondered the problem is Robert Zubrin
16:26an aerospace engineer, author, and ardent proponent of colonizing and terraforming Mars
16:32initially
16:36some of which involved significant violence
16:41he considered hydrogen bombs to melt ice and heat up the atmosphere
16:49or corralling space rocks from the asteroid belt
16:55and crashing them into Mars
16:57but he's had second thoughts about that
17:07I've come to realize that while some of them might be workable in principle
17:12that none of them are really workable in practice
17:16Zubrin's long-range vision of Mars involves people
17:22permanent colonists calling the planet home
17:25and they'd want to survive the process of warming it up
17:29the people who are actually going to terraform Mars
17:33are going to be the people who live on Mars
17:36they are the only ones who will have a significant enough stake
17:40in the outcome of terraforming Mars
17:43to want to expend the resources that would be required to change a planet
17:47so they're not going to want to do things like exploding hydrogen bombs on the South Pole
17:52in fact there is an easier way
17:58and we've been practicing it on Earth for the past 150 years
18:03we know how to warm up planets
18:06we're demonstrating that we know how to do that right here on Earth
18:09where it's probably not a good idea
18:11by burning fossil fuels the carbon remains of ancient plants
18:17we're pumping out carbon dioxide faster than the Earth can take it back in
18:22in the process we're increasing the ability of our atmosphere to trap heat from the Sun
18:29and we're seeing the kinds of results that terraformers would like to see on Mars
18:36warming up planets is something we know how to do
18:41we would do exactly on Mars what we're doing on Earth
18:45we're gonna have to set up literally little factories on Mars
18:50whose intent is to produce greenhouse gases
18:53it would be prohibitively expensive to bring fossil fuel from Earth
18:58and even if it weren't it would take thousands of years to produce enough CO2 to make a difference
19:05but there are more potent greenhouse gases that could be made from materials already on the planet
19:12at Caltech Margarita Marinova has been studying them
19:17exposing them to infrared light to see how efficiently they capture heat
19:22some of them just let that energy pass straight through them
19:25but some of these gas actually absorb the energy
19:28the most potent containing sulfur and fluorine have a super greenhouse effect
19:34thousands of times greater than carbon dioxide
19:37so they're really put a lot of punch in for a very small amount of the gas
19:46chlorine and sulfur are both contained in the Mars soil
19:49so you might imagine these factories pulling in Mars air
19:52scooping up Mars dirt going through a chemical process
19:55producing these super greenhouse gases and releasing them into the atmosphere
19:59in a sense the hardest part of this whole story of warming Mars and introducing life
20:06is that first step
20:08that first step of producing the super greenhouse gases on a planet with no infrastructure
20:13no facilities nothing
20:15everything's got to be built from scratch
20:18McKay estimates that it would take about 100 years to warm Mars to the point where liquid water
20:25could exist on the surface
20:28that means pushing average summer temperatures above 32 degrees in some areas
20:34and generating enough gas to create at least 10 times more atmospheric pressure
20:39the factories could never accomplish that on their own
20:43but they won't have to
20:46just slightly warmer temperatures would cause what's left of Mars ancient CO2 atmosphere
20:53to start gassing out of the ground in the polar ice caps
20:57and stay in the atmosphere year-round
21:00water ice would start to thaw adding vapor to the atmosphere
21:07and water vapor is another potent greenhouse gas
21:12as the atmosphere gets thicker it gets warmer
21:17and as it gets warmer the atmosphere gets thicker
21:19and the process just grows automatically
21:22we'll need to warm Mars roughly 10 times more
21:27than we've warmed Earth with carbon dioxide over the past hundred years
21:32but we'll be doing it with the help of super greenhouse gases
21:36which are thousands of times more efficient than CO2
21:41on Earth we're not trying to warm up the planet
21:43it's happening despite our best efforts to prevent it
21:46imagine if we actually tried to produce greenhouse gases
21:49we maximize their efficiency for warming a planet
21:52and release them on purpose
21:54it's not hard to imagine that we could do 10 times more warming than we're doing now
21:59when the atmosphere thickens to the point where ice can thaw
22:05and remain stable as liquid
22:07the pace of warming could accelerate even more
22:11Phoenix found that a few percent of the surface soil is a carbonate mineral like chalk
22:19satellite instruments have picked up signals that these carbonates may be widespread over the planet
22:28at the same time the rovers have both found minerals that formed in extremely acidic water
22:37virtually sulfuric acid
22:39today the ground is dry
22:44but it may still be acidic
22:46and combined with carbonates
22:48that could be a recipe for making carbon dioxide gas
22:51to demonstrate
22:55McKay mixes carbonate ground up chalk
22:58with simulated Martian soil containing dry acid
23:02and then adds water
23:04so when I add the water
23:06what I expect is that the water will activate the acid
23:09the acid will decompose the carbonate
23:12and CO2 will release
23:15you can see it's happening
23:17you see the gas is being released
23:19it's foaming
23:20I'm pleased to see it
23:22it's not a real surprise
23:23I expected it to happen
23:24but still when you actually try something and it works
23:26that's always a good thing
23:28CO2 is being released
23:30gas is coming out of the soil
23:31the components are there
23:33the acid and the carbonate are there
23:35but without water they don't react
23:37this could be the way we make a thick atmosphere on Mars
23:40just add water
23:46McKay calculates that after 100 years of warming
23:50most of the available carbon dioxide is out of the ground
23:53thickening the atmosphere
23:55and turning the Martian sky blue as it scatters the sunlight
23:59ice thaws and water pools in ancient depressions for the first time in billions of years
24:14as water evaporates vapor builds up in the atmosphere
24:20and it begins to rain
24:26in the colder regions in higher elevations
24:29it snows
24:34we can imagine that after 100 years of warming
24:37Mars has now got a thicker atmosphere
24:40it's got water on the surface
24:42it's got clouds
24:43it's got rain again
24:44from space it would look a lot like Earth
24:48it would look like a blue marble
24:50we would have once again in our solar system
24:52two blue marbles
24:54I think that would be an amazing sight
24:56much of this new blue Mars
24:59would be an icy world
25:01like summer above the Arctic Circle
25:03with atmospheric pressure
25:05equivalent to a mountain twice the height of Mount Everest
25:08but it would be habitable
25:11in a way that Mars today is not
25:13the surface conditions could be fairly pleasant
25:16the real problem is that it's not breathable
25:20it's a carbon dioxide atmosphere
25:22and humans can't breathe
25:24except pure carbon dioxide
25:26there'll be very low levels of oxygen
25:28in with the carbon dioxide
25:29but not enough to breathe
25:30so moving around on Mars
25:32after it's been warmed
25:33you won't need a bulky spacesuit
25:35but you'll need some sort of breathing system
25:37like scuba
25:39the first phase of terraforming is complete
25:45but the next step
25:49turning Mars green
25:51and producing a breathable atmosphere
25:53will be a much longer
25:55and more difficult process
25:57after 100 years of warming
26:15Mars is ready for life
26:17but what could survive here?
26:19Martian soil is something called regolith
26:24pulverized rocks and minerals
26:26that may or may not include
26:28all of the chemical nutrients
26:29required by plants
26:31the Phoenix Lander looked for nitrogen
26:37the most essential nutrient
26:39and didn't find it
26:41but the signal may have been blocked
26:43by other chemical compounds in the sample
26:45unfortunately we don't have any measurements
26:49that directly support or rule that out
26:51but nitrogen is key
26:53you've got to have nitrogen
26:54it's got to be part of the ecosystem
26:56nitrogen was almost certainly
26:59part of the original mix of elements on Mars
27:02and the explosive energy of impacts
27:06may have converted it to mineral compounds in the ground
27:09if so
27:13the soil could be seeded with microbes like cyanobacteria
27:17that can start breaking down those compounds
27:20and get the nitrogen back in circulation
27:23in the process
27:25they'll photosynthesize
27:26turning carbon dioxide into food
27:29and returning oxygen to the atmosphere
27:31paving the way for more complex life
27:34on Mars if we want to have trees
27:38if we want to have plants
27:39if we want to have any life at all
27:41not only got to get it warm enough
27:43but we've got to make sure
27:44that the microbes are there
27:45doing their microbe thing
27:47making their microbe nutrients
27:49that the trees need to grow
27:51even after 100 years of warming
27:58some parts of Mars would still be like
28:00the summit of Orizaba
28:02a polar desert too cold and dry
28:04for any kind of plant life
28:06higher elevations and latitudes on Mars
28:13might never get past this stage
28:15but lower elevations closer to the equator
28:21would be warmer and wetter
28:23more like the lower slopes of the mountain
28:26and on the way down
28:29we can follow a virtual timeline
28:31of the planting schedule on Mars
28:33as the planet warms up
28:35the first plants appear at about 17,000 feet
28:40they grow on the surface of this volcanic rock
28:44and they're part of the first step
28:46that turns this hard rock into soil
28:49the organisms are sliding their way under the rock
28:52and living inside there
28:54because it's a slightly warmer wetter environment
28:57to those organisms
28:59this rock is like a little greenhouse
29:01but by living inside it
29:02they destroy their very house
29:04they release acids
29:05which cause the rock to fall apart
29:07and flake off
29:08bits of rock fall to the ground
29:10you can see them growing down here
29:12in the lower part of the rock
29:13where they're also contributing to
29:15the flakiness of the rock
29:17you can see the algae
29:18they were growing inside the rock
29:20life is playing a role in creating an environment
29:23suitable for life
29:24and this weathering is the first step
29:26in that transformation
29:27around the same elevation
29:30there's moss
29:31in a sense that is what's happening though
29:36these moss and the lichens
29:38they're attacking this volcanic rock
29:40they're turning this mountain into dirt
29:42it's a really hardy little organism
29:45it can survive the high radiation
29:47the low temperatures
29:49make use of very little water
29:51but most importantly
29:52what it does is it photosynthesizes
29:54it takes sunlight
29:55and makes plant material
29:56it makes organic material
29:58that material then goes into the soil
30:00and fertilizes the soil
30:02these guys can take a mountainside
30:04and turn it into a garden
30:06they'll be the first imports of plant life from earth
30:16perhaps fifty to a hundred years after warming begins
30:26lichens and moss thrive on carbon dioxide
30:29and get what nutrients they need from partnerships with microbes and photosynthesis
30:39they build soil
30:40help create more nutrients
30:42and set the stage for what comes next
30:45at about fifteen thousand feet on orizaba
30:52we find grass
30:57the ecosystem is called tundra on earth
31:00a mix of grass and woody shrubs
31:02along with lichens and moss
31:04as the plants grow and die
31:08they enrich the soil
31:11and hold more moisture in the ground
31:13then at thirteen thousand feet
31:16where it's a few degrees warmer
31:18and there's a little more oxygen
31:20tundra gives way to the tree line
31:23a crucial milestone in turning mars
31:26into a truly habitable world
31:28so the tree line is the key
31:35that's what we need on mars
31:38because trees and forests are really going to move mars
31:41from just a warm carbon dioxide rich planet
31:44to a planet with oxygen that's breathable by animals
31:47forests will be the engines that create the oxygen
31:51and that engine of biological productivity
31:53is what will drive mars into a state
31:56that will be a rich and diverse biosphere
32:02research at orizaba finds that forty-one degrees
32:05is the minimum average temperature
32:07for the world's hardiest pine trees
32:14when parts of mars reach that threshold
32:17the planet will be ready for trees of its own
32:23it will begin with high-altitude pine trees
32:26imported from earth
32:30they can handle low oxygen and high radiation
32:36and spread their seeds on the wind
32:39without help from animal pollinators
32:42and so we go from bare volcanic rock to a forest full of life
32:49in fact the tree line on mars will look like the tree line here
32:52on the highest mountain in mexico
32:54these extreme high-altitude trees are the first organisms
32:58that might be producing significant oxygen on mars
33:01it will take generations of work and possibly genetic engineering to get things started
33:08but then the martian forests will spread on their own
33:13improving the soil and the atmosphere
33:16creating a livable world for more than just plants
33:20in the not too distant future humans may have the tools to transform mars
33:37from a cold red desert into a habitable world
33:41but importing life and turning mars green
33:47will raise questions that we've never faced before
33:54we can restore habitable conditions to mars
33:58the fact that we can to me opens up the question should we
34:04what we do will i think set the pattern that will reflect on us as a species for the rest of time
34:12mars will be where we set the precedent and that's why i think it's very important that we do it carefully
34:19there's no sign of life on mars today
34:25and every reason to believe that it can't exist on the surface
34:29the lack of water and shelter from radiation guarantee that
34:34but there could be ancient microbes frozen in the ground
34:39needing only warmer temperatures to wake up
34:41if so they could answer the biggest question in space science
34:47has life originated more than once in the universe
34:51mars and earth have been swapping rocks for billions of years
34:57what's knocked off one planet by an asteroid strike often lands on the other
35:04and it's not inconceivable that microbes have sometimes gone along for the ride
35:12so life on earth may have come from mars or vice versa
35:18which would be interesting but tell us nothing about whether life originated anywhere else
35:25but if martian life turned out to be unrelated
35:31a separate origin just one planet away in our own solar system
35:35that would suggest that life crops up wherever the conditions are right
35:40and a universe with billions of galaxies and trillions of stars could be teeming with life
35:53it might also mean that life from earth could be a threat to martian life
35:58so how should terraformers treat the natives if there are any
36:03it would be best to try to answer that before we started warming up mars
36:08because what we do depends on the answer to that question
36:13if we find that mars has life that's the same as earth's
36:17then it doesn't matter and we move down the path of sharing life from earth with mars
36:23but if we find that mars does have life
36:26and that life is a separate independent origin of life
36:30then we do things completely differently in my view
36:33in that case mckay thinks we should sterilize all of our old space junk left over from previous missions
36:40even hundreds of years later it could still be contaminated with bacteria from earth
36:46and then we should leave mars to the martians
36:52i would say our responsibility is to encourage that life to flourish and thrive
36:59diversity in life across planets is a good thing
37:02and we would learn an enormous amount about how another biosphere based on that life might work
37:08and that knowledge could revolutionize our understanding of fields like medicine and agriculture
37:13as well as helping us understand the earth by having a comparison biosphere
37:20but not everyone would go along with that approach
37:23especially after going to the trouble of making mars habitable
37:28i don't agree that that is a rational ethical position
37:35the ethics need to be based on what is good for people not what is good for bacteria
37:43this idea of depriving humanity of a fully living world not just for humans
37:49but for a wonderful ecosystem of plants and animals and birds and fishes and all of this
37:55in order to preserve this place for bacteria is lunacy
38:02the alternative though is to play the role of the ruthless invader from another planet
38:08you think of the war of the worlds kind of scenarios
38:11and all these creepy science fiction stories about aliens coming and saying
38:15well we want your planet we're gonna kill you
38:18we're friends
38:19that's right
38:20we welcome you
38:22you know we think of that as evil
38:29i mean that's just not being a good neighbor
38:33but i'm fairly convinced that we won't have this problem
38:38because i don't think there is life on mars
38:41but even then there's the question of whether we should tamper with mars at all
38:46whether it's dead or alive
38:48picture the tracks left by the mars rovers
38:55it strikes me there's two different ways you can view that
38:58one is the despoiling of a pristine perfect natural landscape that should have been left alone
39:05it's akin to tracks left by some four wheelers who were driving on some beach and ripping up the dune grass
39:11and you know it's just it's vandalism
39:14that's one way to look at it
39:18the other is picture this evolutionary moment of life coming to a place with no life
39:25to me that's inherently good
39:28in my view if mars is lifeless it really changes the equation
39:32there are a lot of unknowns and we need to understand mars better to be more confident that something won't go crazily wrong that we're not expecting
39:43but it's hard to have a bad consequence on a rock
39:47you know the rock will be a rock and dormant life will stay dormant unless you do something about it and make it a more habitable place
39:55the world we see on mars today is interesting it's beautiful it contains a fascinating scientific record
40:03but in my mind that must yield to the superior value of biology and life
40:10not just human biology and human life but life as a phenomenon that that is the overriding principle biology
40:18because we live on a planet that's so full of life we tend to think of disturbing nature as synonymous with disturbing life
40:29and we don't have much experience with places that are truly truly dead
40:33in my view mars is like the vacant lot next door
40:38why not go there and you know if it really is the vacant lot why not plant a garden
40:44once planted the garden will take on a life of its own and what happens then could shape the future of our species
41:07hundreds of years into terraforming mars pine trees are taking in carbon dioxide
41:13and exhaling oxygen slowly turning the atmosphere into one that may someday be breathable by humans
41:23and as conditions improve so will the potential for a more diverse biosphere
41:30earth's gift is the diversity and richness of its biology and we can share that gift with mars
41:36and so it doesn't have to reinvent all this biology it doesn't have to reinvent flowering plants
41:42it doesn't have to reinvent mammals it doesn't have to go through the dinosaur phase and get walked by an asteroid and wipe them all out
41:49they can do quickly what's taken us a long time to do
41:54when we are bragging to the other planets and the other stars
41:59what do we get to boast about
42:01we earth well we've got life
42:03and if you're nice we'll share it with you
42:06the lesson so far
42:09from the Orizaba tree line
42:11is that nothing exists on its own in a complex ecosystem
42:15trees grow where it's warm enough and wet enough for microbes to produce nutrients in the soil
42:21and microbes thrive where trees and other plants cycle organic material back into the ground
42:34one of the lessons we get from studying ecosystems on earth is that an ecosystem is not just a single plant or a single type of plant
42:41it's a whole community of organisms microbes plants all sorts of life forms growing together in a system
42:50for mckay investigating the links between a living biosphere in mexico and a potential biosphere on mars
42:58opens a window on the nature and the future of life
43:02these are questions that i think are very deep and very important and to me they connect to this mundane detail
43:09of making this measurement and that measurement in a glorious sort of way
43:13planetary science gives one an opportunity to think in terms of millions of years or hundreds of millions of years
43:20and to think about what's going to happen to the earth what's going to happen to mars
43:24the question of the future
43:26mckay calculates that it could take 100,000 years for trees to transform an icy blue mars
43:35with a carbon dioxide atmosphere into a warm green planet with enough oxygen for humans to breathe
43:42but that's with present-day technology future terraformers may find a faster way
43:50we are in the position of a 20th century mind trying to solve a 22nd century problem
43:57200 years from now they'll say wow these guys they lived in the second half of the 20th century and they're talking about terraforming mars
44:09how prescient but doing it with fluorocarbon gases and green plants how 20th century can you get
44:18they will accomplish this with 22nd century technology
44:35we can't predict exactly what a fully terraformed mars would look like
44:39how warm wet and diverse it might become
44:46water will fill low-lying basins probably frozen at higher latitudes in the winter and open in the summer
44:54high elevation terrain may be cold desert and dry grassland
45:02and the highest like the summit of the 85,000 foot olympus mons volcano
45:09will be a reminder of what mars was like before terraforming
45:15but what happens to a martian biosphere over thousands of years
45:19can be no more than a guess
45:22where does mars go at the end?
45:24it's a question i think about a lot
45:26i think it's clear that mars will go to this
45:29it'll go to forests and trees
45:31but where will those trees then take the planet?
45:34we won't have any control over that
45:36mars will follow its own evolutionary trajectory
45:39if it follows the trajectory that earth followed
45:42then the oxygen will build up and it will become a planet suitable for life like us
45:50but maybe mars isn't going to go quite that way
45:53and it's going to end up moving in a path that we can't predict
45:56it's not a problem if mars has a mind of its own
46:00it's a good thing
46:01and for us as humans it's a good thing
46:03because we will learn more about planets
46:05than by having just another exact copy of the earth
46:15it may be fifty or a hundred years from now
46:18but eventually humans will be living on mars
46:21and it's not too soon to consider the choices we'll face when we get there
46:26that's fascinating to me
46:28the notion that we as a species can ask that question
46:31what are we going to do when we get to mars
46:33i want to see that dialogue happen
46:36i want to see us as a species discussing it
46:38because we're on the verge of getting to mars
46:40we can see that
46:41that's not something for five hundred years in the future
46:43some distant new technology
46:44that's us
46:45we're going to mars
46:46it's the nature of humans to explore
46:55to investigate everything within reach
46:58it's the nature of life to fill every available niche
47:05and mars will someday be available
47:09just as birds transport the seeds of life to barren islands
47:18and turn them into lush places
47:20instead of just barren rocks with a few bacteria on them
47:23we're the kind of bird as it were
47:25that can take the seeds of life from earth
47:27and transport it to the barren islands
47:29that exist in space right now
47:31and turn them into bountiful living worlds
47:35so i think we will do that someday
47:39we'd be less than human if we didn't
47:42along the way we may learn something about how living planets work
47:48and how to keep them alive
47:50the primary benefit the citizens of earth will derive
47:54will be knowledge
47:55and it'll be knowledge that may also have practical benefits
47:58in managing our own planet
48:00no matter what we do in space
48:03we are going to have to manage the earth
48:05and mars is not an excuse to mismanage the earth
48:08in fact we have to view it the opposite
48:10mars is part of the lesson plan
48:12in learning how to manage the earth
48:18Mars lost its early atmosphere in part because it was small
48:22and lacked the internal heat necessary to keep it going
48:26a terraformed mars would eventually suffer the same fate
48:33but it would happen very slowly over tens of millions of years
48:38eventually mars will lose its atmosphere
48:45it won't be habitable forever
48:47but then nothing is forever even the earth won't be habitable forever
48:51in the far distant future as our aging sun grows larger and hotter
48:58the inner planets mercury venus earth and mars will be burned to a crisp
49:06if anyone still lives in our solar system by then
49:13they will have long since moved on to better neighborhoods
49:18perhaps one of the moons of saturn like titan
49:22or farther on to another star system
49:25if so mars may be the place where their distant ancestors first learned
49:31how to live on another planet
49:34Mars may be the place where their distant ancestors first learned
49:36how to live on another planet
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