Mars is infested with robots, orbiting the planet and roaming the Martian surface on a mission to uncover its secrets; now, Perseverance joins this dedicated group of machines to uncover if there is, or was ever, life on the Red Planet.
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LearningTranscript
00:00our neighbor Mars fascinates us it's a planet that is similar to Earth but with
00:11some big differences Mars is rusty dusty frigid and frozen it ain't the kind of
00:17place you want to raise your kids past missions suggest that Mars was once a
00:24very different world the Mars we see today has completely changed from the
00:29Mars of a few billion years ago if I had a time machine to visit Mars in the past
00:34I would go in an instant without a time machine to explore ancient Mars we employ
00:41a team of high-tech robots investigators we've got an entire fleet of robotic
00:49spacecraft exploring the planet working together they dig into Mars's past to
00:56answer the ultimate question did Mars once have life
01:01February 2021 the newest robot investigator speeds towards Mars the most advanced rover NASA has ever
01:28sent to another world this is perseverance the goal of the perseverance mission is to look for signs of
01:37past life on Mars first it must navigate safely to the surface of the planet every landing has its own
01:47dangers because the rover must be autonomous it has to do everything without our help perseverance enters
01:56Mars's thin atmosphere at close to 12 and a half thousand miles an hour
02:00and deploys a parachute navigation has confirmed that the parachute has deployed and we're seeing significant deceleration in the velocity
02:15the parachute slows perseverance to 200 miles an hour current velocity is 83 meters per second at about 2.6 kilometers from the surface of Mars
02:28still too fast to land safely
02:32to prevent a violent impact the rover must activate the sky crane
02:39when I first saw the sky crane concept I thought the engineers are kind of losing it it seemed to me like a really crazy idea
02:49perseverance activates its jetpack
02:57retro rockets slow the lander's descent to a crawl
03:04then 66 feet above the surface the sky crane uses cables to gently lower the rover to the ground
03:20Tango Delta
03:22Tango Delta
03:23Touchdown confirmed
03:25Perseverance safely on the surface of Mars
03:28ready to begin seeking the sands of past life
03:37Step one in the search for Martian life
03:39find evidence of liquid water
03:42a good place to start is the 28 mile wide Jezero crater
03:48Perseverance has landed in a crater called Jezero
03:52and this looks like a place where there was liquid water in its past
03:55and the reason we think this is because there's this beautiful delta deposit right in the middle
04:00Perseverance turns its high resolution cameras onto a cliff side in the crater
04:07and discovers giant five-foot boulders near the top
04:13a clue to how they got there may come from the first probes to visit Mars
04:20one of the very first things we noticed about Mars when we first sent probes there with Mariner and Viking
04:26was that there were these huge channels on the surface of Mars
04:30looking at these enormous landforms we realized that in some places on Mars
04:36there may have been enormous floods
04:39bigger than almost anything we'd ever seen on Earth
04:43Flash floods on Earth cause similar rock formations to those found in Jezero crater
04:49suggesting that powerful fast-moving torrents carried the giant rocks found by Perseverance
04:56and dump them at the top of the cliff
05:05Perseverance is just one member of an elite team of robots patrolling the ground and spying from the air
05:12the Mars Atmospheric and Volatile Evolution Orbiter
05:18or MAVEN investigates Mars' atmosphere
05:21MAVEN smells really good
05:25it smells the Martian atmosphere
05:27it tells us what the Martian atmosphere is made of all across the planet
05:31then there's the Mars Reconnaissance Orbiter
05:35as its name suggests an orbiting spacecraft that images the surface of Mars
05:39the MRO's high-resolution cameras can identify surface features as small as a kitchen table
05:46and joining the orbital crew the European Space Agency's Mars Express
05:54with its ground-penetrating radar it searches for evidence of subsurface water
06:00and on the Martian surface a group of high-tech landers take a closer look
06:08including the team's quake specialist InSight
06:12this lander probes deep beneath the surface
06:15to discover how Mars' interior shapes the planet over time
06:21the InSight lander on Mars has a really simple concept
06:24you land a spacecraft on the surface anywhere on Mars
06:27and then just listen for Mars quakes
06:29and 300 miles south of InSight veteran rover Curiosity
06:35Curiosity is exploring the Gale Crater
06:39The mission goal for Curiosity is to look for habitability
06:43and so that's environments in which life as we currently understand it could exist
06:47Curiosity searches for evidence of calmer, more permanent water in Mars' past
06:57investigating layers of rock at the base of Mount Sharp
07:01a three-mile-high mountain in the middle of the crater
07:04The rock layers start way up at the top of Mount Sharp
07:08and they move progressively downward
07:10and basically we're going backwards in time
07:12until we get to the very bottom
07:14and the very bottom is actually really old
07:16Mount Sharp was built over millions of years, layer by layer
07:21The rocks at the base of the mountain date to three and a half billion years ago
07:28These rocks are made up of very fine layers
07:32and could only have been formed in calm water
07:36These sedimentary layers were formed when Gale Crater was a lake
07:40and sediment settles out and you get these beautiful layers
07:42Curiosity explores more of Gale Crater
07:48and discovers rounded pebbles like those we find on Earth
07:55When you see a rounded pebble on Earth, you know that that got rounded in a river channel
08:00Some of them used to be angular but their angles all got knocked off
08:03by being rolled and rounded and moved by water
08:07So we're very excited when we see rounded pebbles on Mars
08:13The rock layers and rounded pebbles tell us
08:17that over three billion years ago, Gale Crater was a lake fed by rivers
08:24It was so exciting to understand liquid water in the context of Gale Crater where Curiosity is
08:29and that's just because what we see there is this long lasting fresh water lake
08:34and that's not like anything else we've seen on Mars before
08:37Imagine standing on the edge and looking out at this big beautiful blue lake shining in the distance
08:44What if there were just a whole array of craters filled with water off in the distance?
08:50It would be so beautiful
08:51And a good place for life to evolve
08:55Mars was a nice place
09:00It was probably more like Earth is now
09:02So it wouldn't surprise me if it supported life
09:05We're talking microbial life
09:07We're not talking, you know, Marvin the Martian or anything like that
09:10But life still is life
09:17Any water Mars once had is now long gone
09:25To stay liquid, water needs warmth and atmospheric pressure
09:31So, hundreds of miles above the planet
09:34Orbiting members of the team investigate the mystery of Mars' missing atmosphere
09:42While robot team members Curiosity and Perseverance work the Martian surface
09:56Eight probes orbit the planet
10:00Searching for clues about Mars' ancient wet history
10:05Leading the pack is MAVEN
10:12Its mission? To solve the mystery of Mars' lost atmosphere
10:17Today the atmosphere of Mars is incredibly thin
10:21It's only about 1% the atmospheric pressure here on Earth
10:24The weight of gas in an atmosphere pressing down creates pressure
10:29And that pressure dictates at what temperature liquids boil
10:40Here on Earth at sea level
10:42The boiling point of water is about 212 degrees Fahrenheit
10:46But up here in the mountains near Denver
10:48We're at a higher altitude
10:50We've got a lot less atmosphere pressing down on us
10:53And so it boils at a lower temperature
10:55Let's put a thermometer in here
10:57There's 200 even right there
11:04That's a lot cooler boiling temperature than at sea level
11:07Now, if you go to even higher altitudes
11:10At 100,000 feet here on the Earth
11:12The air pressure is about what it is on the surface of Mars
11:15On the surface of Mars, water will boil effectively ambient temperature
11:19We wouldn't have to heat it at all
11:21You just put a glass of water on the surface of Mars
11:24And it'll boil and disappear away
11:28But the planet's surface tells us that dry Mars was very different in the past
11:34When you see things like river channels that probably took millions of years to carve
11:39That gives you an idea that the atmosphere was once very, very different
11:43It had to be thick to allow liquid water to exist on the surface
11:50To investigate what happened to that thick Martian atmosphere
11:55MAVEN swings into action
11:58One of the main objectives of the MAVEN mission was to measure argon on Mars
12:02There are slightly different kinds of argon
12:05We call these isotopes
12:07And basically it means that there's just an extra neutron in the nucleus
12:11So there's one type of argon that's just a little bit heavier than the other type
12:15Just by one neutron, not by much
12:19High up in the atmosphere
12:21MAVEN tag teams with Curiosity down on the surface
12:26They measure the amount of light and heavy argon
12:32Now, what's special about argon?
12:33Well, argon is not very reactive
12:35It doesn't really get involved in a lot of chemistry
12:37It's not really absorbed by rocks
12:39It doesn't change much
12:40Once it's emitted, it kind of hangs around
12:42And that makes it very valuable
12:44Because it means it stays in pretty much its pristine, pure form
12:47Through the history of the planet
12:50When the researchers back on Earth compare the readings
12:53From the two Martian robots
12:55Something doesn't add up
12:58With curiosity on the surface
13:00We see a certain ratio of heavy to light argon
13:03And we expect that same ratio to exist up in the atmosphere
13:07But with MAVEN, we see a different ratio
13:11We see far less of the light argon than we do down on the surface
13:15So something is messing with that ratio
13:20The only thing we can think of that can mess with the ratio of argon
13:24Is the solar wind from the sun
13:32The sun spits out a constant stream of particles
13:35Called the solar wind
13:37The wind is over a million degrees Fahrenheit
13:40And travels at up to 500 miles a second
13:43When it reaches Mars
13:46It strips away gases high up in the atmosphere
13:49The lighter the argon is
13:51The lighter the argon is
13:52The higher it gets up into the atmosphere
13:54That means that that gets blown away
13:56Preferentially by the solar wind
13:58The heavier argon stays a little bit lower down
14:01And a little bit more protected
14:02So when you look at the ratio in the atmosphere
14:04Of the light argon to the heavy argon
14:07It gives you an idea of how much has been lost over time
14:10MaVEN's data reveals that Mars has lost 65% of the argon from its atmosphere
14:20And the solar wind continues to bombard the planet
14:25The atmosphere of Mars is being stripped away by solar radiation
14:28By a quarter of a pound every second
14:32This rate of atmospheric loss leads to one conclusion
14:36The solar wind robbed Mars of its once thick atmosphere
14:43And with it, the planet's water
14:46But a question remains
14:49We know that Mars' atmosphere was much thicker in the past
14:53Really similar to Earth's
14:55So why is it that Earth's atmosphere is still mostly there
14:58Whereas Mars' has been stripped away?
15:01Earth has a protector
15:04A magnetic field that shields our atmosphere
15:08From the ravages of the solar wind
15:11The Earth's magnetic field is generated deep in the core
15:15There are actually two cores
15:16There's a solid inner core and a liquid outer core
15:19And that solid inner core is delivering heat to the outer core
15:23And as it does this, it causes convection currents
15:26The convection currents pull electric charges around
15:31And cause magnetic fields to fold in on themselves
15:35We call this a dynamo
15:37And this is what's capable of generating powerful magnetic fields
15:43The magnetic field forms a protective bubble around Earth
15:47That deflects the solar wind away from our planet
15:50Did Mars once have its own force field?
15:57To find out, Maven homes in on some ancient volcanic rocks
16:02On the Martian surface
16:05It detects faint magnetic traces
16:09Martian rocks, typically in the form of lava, become magnetic
16:15When the iron particles in the rocks become aligned with the magnetic field
16:20That's active at the time
16:22And then as the rock cools, those things get frozen in place
16:24That sort of freezes the magnetic field into place
16:27What that tells us is that these volcanic materials were erupted at a time
16:32Where there was a magnetic field present on Mars
16:35Dating the magnetized rocks reveals that Mars
16:40Had an active magnetic field for almost a billion years
16:47This means that the atmosphere of Mars was protected for those billion years
16:53And if the atmosphere was protected, the liquid water was protected
16:57And if that liquid water was a home for life
17:00Then that life was protected
17:02But something happened to bring Mars' force field down
17:09To discover what?
17:12Our quake specialist, InSight
17:15Is ready to burst open the mystery of the planet's lost protective shield
17:20Robots are rewriting the history of Mars
17:35They found that Mars once had a magnetic field that protected its atmosphere
17:41Now, another team member, InSight, probes the planet's interior
17:48Its mission? To discover if the secret of the planet's lost magnetic field
17:55Lies beneath the Martian surface
17:58InSight was developed with the world's best seismometer
18:01This is a really precise, really delicate, really sensitive instrument
18:05And it just was placed on the surface and started listening
18:102021
18:12InSight listens for seismic vibrations called Marsquakes
18:17As they travel through the planet's interior
18:20It's detected quite a few Marsquakes
18:22But these were very small
18:24But then it detected two much larger ones
18:31And these were interesting
18:32Not only were they more powerful
18:34But they were coming from the direction of Cerberus Fosse
18:37Which is a very interesting region on Mars
18:39The magnitude 3.1 and 3.3 quakes came from Cerberus Fosse
18:48A series of trenches that stretch for 750 miles across the Martian surface
18:54Some fissures cut through impact craters that are only a few million years old
18:59This means Cerberus Fosse must be younger
19:07InSight teams up with the Mars Reconnaissance Orbiter flying hundreds of miles above
19:14This eye in the sky spots an ancient lava flow spreading out over a three-mile area
19:21Dating of the flow reveals that it's recent
19:24The Mars Reconnaissance Orbiter spotted in the Cerberus Fosse region
19:31Some lavas that appear to be about 50,000 years old
19:35This is crazy young for Mars
19:38Mars has been around for billions of years
19:4150,000 years is nothing
19:43Humans were around on Earth that long ago
19:45So this is really recent
19:47Based on the fact that we had these two Marsquakes recently
19:51Plus the evidence of the volcanic eruption just 50,000 years ago
19:56I mean now we cannot say that Mars is dead
19:59We have to say Mars is active
20:03A volcanically active Mars suggests its interior may still be warm
20:09If it is, why did the planet's magnetic field die?
20:13InSight probes deep into the interior of the red planet using vibrations from small Marsquakes
20:23InSight uses these to kind of construct what the interior of Mars was like
20:28Because these waves bounce off different layers inside the interior of Mars in different ways
20:34InSight's seismometer builds a picture of Mars by completely redrawling the map of the interior of the planet
20:44It turns out the crust is thinner than we thought
20:47It's only 12 to 23 miles thick
20:50So there's this whole picture of Mars that is unfolding in front of us that is vastly different than we ever predicted
20:57InSight's new and improved layout of Mars reveals a 969 mile deep mantle surrounding a metal rich core
21:08New analysis of data from InSight reveals the size of the core of Mars
21:15And we haven't had this before, it's so exciting
21:17It's about 1100 miles in radius
21:20This is a little more than half the radius of the body which is pretty big
21:24And is much bigger than we expected for the size of the core of Mars
21:27Mars' larger core makes up about a quarter of the planet's mass
21:34And InSight's journey to the center of Mars reveals another surprise
21:39We have always thought that the core of Mars was long since solidified and wasn't warm at all
21:46And InSight is now showing us that actually part of the core is probably still molten, which is shocking
21:53There's a liquid core at Mars, I mean this is crazy
21:58Data from past missions may help explain why Mars' core is still liquid
22:07Scientists discovered high levels of sulfur in the crust
22:11Mars seems to have a bit more sulfur, at least in the surface, than Earth does
22:15If we extend that composition to the core and add more sulfur to the iron-nickel core
22:22That would actually reduce its melting temperature, making it possible for this core to be molten today
22:30We thought that Mars lost its magnetic field when the core cooled and solidified
22:36A molten core changes everything
22:40Well how can we explain this lack of a magnetic field at Mars, even though there's a liquid core?
22:45Well, in order to have a magnetic field, you need the fluid to be moving and rotating and convecting
22:52Over time, as Mars lost heat and cooled down, its core stayed molten, thanks to the sulfur
23:00But with less heat, there was not enough energy to power the churning convection of liquid metal
23:06That creates an electric current
23:09The convection in that core would have slowed down to the point where no magnetic field would be generated
23:153.7 billion years ago, Mars' magnetic shield dies
23:23The solar wind's relentless attack strips the planet of its atmosphere
23:29As the atmosphere disappears, water on the surface gradually boils away
23:35But, did all of the planet's water dissipate?
23:44To find out, our robots once again, team up
23:49Since the first probe visited Mars in 1971, 16 missions have investigated the red planet from orbit
24:07While 10 landers have explored the surface
24:11They've revealed Mars may still be an active planet, one that once had the right conditions for life
24:22Mars used to be thought of as this dry, arid, inhospitable environment
24:27And thanks to the recent Mars missions, we know now that it could have sustained life
24:32Could there be any ancient Martian water left hidden inside the planet today?
24:39Maven investigates by analyzing Mars' atmosphere for one of water's components, hydrogen
24:46The MAVEN mission is looking at hydrogen that's currently in the Mars atmosphere
24:53This is a really important thing to study
24:57The gas is produced when the solar wind slams into Mars' thin atmosphere
25:03And smashes apart molecules of water into hydrogen and oxygen
25:07Hydrogen molecules come in two forms, light, regular hydrogen, and the heavier, deuterium
25:17The ratio of the different types tells us about the history of water on the red planet
25:24It turns out that it's much easier to lose the lighter version
25:28Because gravity just can't hold on to something that's light as easily as a heavier thing
25:32So we expect that as time goes on, we'll have less and less light hydrogen and more and more heavy hydrogen
25:39So if we can measure the outflow of hydrogen from the Martian atmosphere today
25:46And specifically whether that's light or heavy hydrogen
25:50We can start to get some kind of idea about how much water has been lost from Mars
25:56And therefore how much might still be there today
25:582021
26:02Scientists at Caltech analyzed data from Mars' rovers and orbiters
26:07To discover the ratio of deuterium to hydrogen in the atmosphere
26:13They find less of the heavy hydrogen than expected
26:17If Mars had lost a lot of its original water out into outer space
26:22We'd expect to find lots of heavy hydrogen left behind in the atmosphere
26:30But in fact what we found was that the ratio told us that Mars didn't lose much of its water upwards
26:38And so maybe the water went downwards
26:41Where is Mars' water hiding?
26:46Some scientists think it could be stashed away in the Martian rocks
26:51When we look at a rock, we often think this is a really dry thing
26:56There's no water in there, but in fact there's often a lot of water in rocks
26:59And it's because it's bound up in minerals
27:03Changes in the crust can drive these minerals to suck up huge volumes of water
27:09Equivalent to a global layer over 300 feet deep
27:14Researchers estimate that as much as 99% of Mars' water could be locked away below the surface
27:21And Mars hides water in other ways too
27:27Enter the European Space Agency's orbiter, Mars Express
27:32Probing one mile beneath the Martian South Pole
27:36It finds a secret store of water
27:40Really exciting, we've discovered a system of lakes beneath the Martian polar ice cap
27:48Lakes of what appears to be liquid water
27:53Now these lakes are not very deep
27:56They're probably only a couple of feet deep
27:57Maybe in some places even a couple of inches deep
28:00But they're quite large
28:01Some of these are about 20 miles across
28:04And there's even some suggestion that these are connected with channels
28:08Kind of a system of very shallow great lakes near the south pole of Mars
28:13The Martian poles are the coldest regions on the planet
28:16Temperatures can reach 200 degrees below zero
28:21So why is it that underneath this cold ice you might even find liquid water?
28:27Well, remember you're actually going down closer into the interior of Mars there
28:32And so that's warm
28:34It's possible that the geologic activity inside Mars is warming the ice from the underneath
28:38But heat from the interior of Mars wouldn't be enough to keep these lakes liquid
28:45The secret ingredient may be salt
28:50If you've ever spread salt on an icy driveway
28:53You'll notice that where the salt hits the driveway the ice begins to melt
28:57Salt water actually freezes at a much lower temperature than water that's fresh
29:02So if it's salty water it could actually stay liquid at lower temperatures
29:07We still aren't 100% sure that the lakes are completely liquid
29:12Some scientists think they could be lakes of frozen clay
29:16Until we have a rover that can explore beneath the poles
29:20We won't know for sure
29:21The only real way we can tell for sure is to send some kind of mission that drills right down through that polar ice
29:32And samples what we find at the bottom
29:35Wherever it may be hiding, Mars' water is locked away
29:41But in its past, the planet had impressive lakes and rivers
29:45Did they ever host life?
29:48To find out, the rovers take a deep dive into Mars
30:08Veteran crew member Curiosity explores the Gale Crater
30:12The rover's mission?
30:15To find evidence of whether Mars could have supported life
30:21Los Alamos National Laboratory
30:24Principal investigator of Curiosity's ChemCam
30:28Nina Lanza works closely with the rover patrolling Mars
30:3234 million miles away
30:35In many ways, Curiosity is like my first child
30:38We had to take such good care of her while she was still here on Earth
30:40But like all children, she had to forge her own path
30:44And so we had to send her on her way to discover new things on Mars by herself
30:53ChemCam uses a precision laser that analyzes the chemical composition of Martian rocks
31:00We have a laser that we focus onto a target up to 23 feet away
31:04And we vaporize a little material
31:07And then we look at the light made by this vaporized material
31:11And figure out what elements are in the rock
31:15Working with an instrument like ChemCam is really a childhood dream come true
31:20Because I was always hoping to work on a spaceship
31:23And today, I work on a spaceship with lasers
31:26How cool is that?
31:28With their long-distance teamwork, Nina and Curiosity discover rocks with a shiny coating
31:34Laced with manganese
31:37One of the most exciting discoveries from Curiosity in Gale Crater
31:41Was the existence of high concentrations of an element called manganese
31:45And that's because manganese on Earth is very closely tied to life
31:49Could the manganese of Mars be linked to life forms?
31:55To investigate, scientists look at similar coatings called varnish on desert rocks here on Earth
32:03So I have an example here of some rock varnish
32:06And you can see it's actually incredibly dark
32:09It has a lot of iron oxide, manganese oxide and clay minerals in them
32:13And the rocks can sometimes have none of these things in the rock itself
32:16So the question is, where does this coating come from?
32:21Often we find microbes associated with the varnishes
32:25And so, possibly, these microbes actually help fix the manganese onto the surface
32:31The age of these Earth varnishes may provide a clue to Mars' distant past
32:38Here, they only appear after a significant event in our history
32:42The creation of the oxygen we breathe
32:47A couple of billion years ago on Earth was the great oxygenation event
32:52Basically, the Earth's atmosphere did not have a lot of oxygen in it
32:57It was locked up in minerals and chemicals
32:59Well, some bacteria discovered how to photosynthesize light
33:04How to convert energy from light into their metabolism
33:06And via the chemistry of this, they wound up emitting oxygen
33:11The oxygen was poison to many life forms
33:17So they died out
33:19But others thrived, pumping more and more oxygen into the atmosphere
33:25Oxygen reacts with the manganese, binding it to the rocks
33:29We don't really see these minerals until after the rise of oxygen in the atmosphere
33:36So after photosynthesis
33:38For Mars to have these same manganese varnishes
33:43There must have once been more oxygen in the planet's atmosphere
33:48Is it possible that Mars had a lot of oxygen in its atmosphere in the past
33:52And there were wee little beasties processing it
33:56And so the search continues
33:59And Curiosity uses another piece of equipment
34:02To sniff out traces of past Martian life
34:06One of the key instruments aboard Curiosity
34:09Is a piece of lab kit called a gas chromatography mass spectrometer
34:15Or GCMS
34:16And all this really is, in essence, is like a very sensitive electronic nose
34:25Curiosity digs up some Martian soil
34:28And heats it in its portable chem lab
34:33Like a robotic bloodhound
34:35It sniffs the vaporized dirt
34:38And picks up the faint smell of a rare molecular compound
34:42What Curiosity discovered was a compound called thiophene
34:48This is interesting, because at least on Earth
34:51Thiophene is often found in fossil material
34:55In coal, in oil
34:57As well as stromatolites or microfossils
35:00Of ancient life in the fossil record
35:02So maybe this thiophene we've now discovered on Mars
35:07Is some trace chemical fossil of ancient Martian life
35:13Or possibly it was produced by non-biological processes
35:23Curiosity is knocking on the door of finding the evidence for life on Mars
35:28We haven't found life, but we've found the interesting bits that are pieces of the puzzle
35:34The organic puzzle of life on Mars
35:37And so it's getting us to that ultimate question
35:39Is there or was there ever life on the planet?
35:44To help answer that question, scientists bring in pinch hitter Perseverance
35:48The newest member of the crew has the latest tech
35:51Tools designed based on lessons from previous missions
35:54Perseverance is so important because it leverages all of the knowledge of the previous rovers
36:03Which set the stage for taking samples on the surface of Mars
36:07Searching for life and setting up a place for humans to explore in the future
36:13Perseverance gathers rock and soil samples
36:17Testing some itself and leaving others to be collected and return to Earth later
36:23We are just at the beginning of the Perseverance mission
36:27We have so much to learn
36:29But I think all of us would be so thrilled if we could actually find definitive signs of past Martian life
36:36That would be incredible
36:38I don't know what form that would take
36:40But we're going to look for it in every way that we know how
36:42While Perseverance hunts for evidence of ancient life on Mars
36:49Curiosity detects hints that life may exist on the red planet now
36:56In Gale Crater, Curiosity detects a huge surge of methane gas
37:14The methane we've detected in the atmosphere of Mars is potentially very very exciting
37:22Most of the methane in our own air in Earth's atmosphere is biogenic
37:28It was released by living organisms
37:31Curiosity's result is exciting because we know that this can't be ancient methane
37:37Methane
37:39Methane is really interesting because it has a short residency time in an atmosphere
37:44Which means it breaks down very quickly
37:46Whatever is making methane in Gale Crater is doing it right now
37:51Curiosity has detected methane many times before
37:57But this is the largest amount so far
38:00Question is, what created it?
38:03Maybe this Martian methane is the first trace we found of Martian life
38:11Microorganisms living deep underground
38:14Or maybe that methane is not biological but geological
38:22It's methane that's been given off by volcanic processes in the past
38:27The frustration is we can't quite tell the difference between the two just yet
38:32All we can do is continue to sniff the air and document when and where we see it
38:37The picture becomes more intriguing when curiosity detects oxygen in greater quantities than expected
38:48There's a lot more oxygen on Mars than we had suspected
38:54Which is weird in the first place
38:56And the amount of oxygen is changing seasonally
38:59There's something in or on Mars that is adding oxygen to the Martian atmosphere during the spring and summer
39:11And then taking it away during the fall and winter
39:14There is something that is actively controlling the amount of oxygen in the Martian atmosphere
39:20What is that?
39:22Most of Earth's oxygen comes from living organisms photosynthesizing
39:27And it changes with the seasons
39:30We have normal, cyclical, seasonal variations in the amount of oxygen here on Earth because of life
39:39The most land mass on the Earth is located in the northern hemisphere
39:44And so that means that during northern summer most of the oxygen on Earth is generated
39:49So there's a peak in oxygen during the northern summer
39:52So where is the oxygen on Mars coming from?
39:55Oxygen is a known result of life, of photosynthesis
40:03It's a biosignature, it's a sign of life
40:06Is this a sign of life on Mars?
40:10The atmospheric changes in oxygen and methane are a fascinating puzzle
40:16And a tantalizing hint of life
40:19Life on Mars explaining these changes in methane and oxygen would be incredibly interesting
40:25So it's probably wrong
40:30The answer is probably more boring
40:33And not that chemistry is boring, but it's a little less interesting than life
40:37We Mars scientists, of course, are always very excited about seeing signs of maybe extant life on Mars
40:43But we're going to require really big proof before we feel truly excited that we've made this discovery
40:47The Army of Robotic Explorers continues to rewrite the story of Mars
40:58Discovering a once warm, wet world with the potential for life
41:02Now, a new generation of robots led by Perseverance will dig deeper into the red planet's troubled past and its frozen present
41:16And maybe hit the mother load, life itself
41:20With every new mission to Mars, I hope that somebody really is going to find evidence that life either existed there in the past or maybe even still does now
41:31And with all of these missions on many places on this planet, maybe now is the best time to actually answer that question
41:38Whether or not it's likely that Perseverance finds life on Mars, we have set ourselves up for success
41:45And I am so hopeful that we get to finally answer that question, the big question
41:52Are we alone?
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