The Planets: Mars

Transcript

The Planets: Mars

PBS Airdate: July 24, 2019

NARRATOR: Two rocky worlds, formed at the same time, now close neighbors, one blue with oceans and full of life…

JENNIFER EIGENBRODE (Participating Scientist, Curiosity): Earth has got this rampant biosphere.

NARRATOR: …the other a barren desert.

JENNIFER EIGENBRODE: If you look at Mars, it’s a red, dusty planet. It’s super dry.

NARRATOR: But it hasn’t always been that way.

ASHWIN VASAVADA (Project Scientist, Curiosity): There’s a lot of evidence for ancient flowing water on Mars.

STEVE SQUYRES (Principal Investigator, Opportunity): It was a bizarre discovery. It was startling.

NARRATOR: Stunning findings reveal a deep mystery…

JOHN GROTZINGER (Project Scientist, Curiosity 2007–2015): Why is Mars so different from Earth?

NARRATOR: …daring us to explore…

ASHWIN VASAVADA: We knew it landed safely when we realized that the wheels sensed the ground. We had successfully landed on Mars.

NARRATOR: …and discover.

JENNIFER EIGENBRODE: What we found in those rocks is a turning point for us. Finding the organic matter is the clue to searching for life.

NARRATOR: And if life did evolve in its ancient oceans, what happened to it?

STEVE SQUYRES: How far along did it get? And did it go long enough that life could have taken hold there?

JOHN GROTZINGER: It opens up the possibility that the universe is full of life.

NARRATOR: The Planets: Mars, right now, on NOVA.

MISSION CONTROL: We’ve entered orbit around the planet Mars.

MARS

142 MILLION MILES FROM THE SUN

NARRATOR: Mars: our planetary neighbor is a barren desert world, its surface red with rusted rock and parched sand. But beneath the dust, Mars bears the scars of a former life.

Four-billion years ago, Mars was a very different world, its atmosphere dense enough to support seas and rivers of running water, what we believe are the conditions for life to emerge.

But today that vibrant world is gone. Its rivers run dry, oceans evaporated, while clearly visible from the Red Planet’s surface, is its neighbor, Earth, blue with oceans and teeming with life.

JENNIFER EIGENBRODE: On Earth, we have this amazing biosphere that is super-vigorous. There’s an ocean, all sorts of things are happening. If you look at Mars, it’s a red, dusty planet. It’s super dry.

JOHN GROTZINGER: One of the questions is why are they different? Earth has a thick atmosphere, Mars has a very thin atmosphere; Earth is warm almost everywhere, Mars is freezing cold almost everywhere. So, these are very different planets.

JENNIFER EIGENBRODE: But if you go back into the past, about four-billion years ago, the two planets were probably very similar.

THE SOLAR SYSTEM

4.6 BILLION YEARS AGO

NARRATOR: Four-point-six-billion years ago, an innocuous cloud of dust and gas is collapsing, forming the embryonic sun. Swirling around it, the remnants of the dust cloud are slowly drawn together by gravity, forming eight new worlds, amongst them, our smaller neighbor. Mars and our home planet, Earth, are both rich with elements, like carbon, metals, like iron, and, crucially, water. But despite many similarities at birth, their differences in size and distance from the sun set them on very different paths.

JENNIFER EIGENBRODE: These two planets started off very similarly.

JOHN GROTZINGER: It’s what I like to call “comparative planetary evolution.”

JENNIFER EIGENBRODE: The same things could have been happening at the very beginning of their existence.

JOHN GROTZINGER: And then, as the clock ticks forward geologically, they actually become very different from each other. And that’s the fascinating part.

JENNIFER EIGENBRODE: What’s happened since? If they looked and acted similar in the very beginning, and life formed on one planet, possibly on the other, then what happened?

MARINER FOUR MISSION CONTROL: Five…

NARRATOR: To find out has taken decades…

MARINER FOUR MISSION CONTROL: …four, three, two…

NARRATOR: …of pioneering exploration.

MARINER 4

1964

NEWS AUDIO ARCHIVE FOOTAGE: Mariner 4 was successfully launched, on time for its historic 228-day-journey to Mars.

NEWS AUDIO ARCHIVE FOOTAGE: Picture information started to come in on July 15th, 1965.

THE FIRST CLOSE UP PICTURES OF MARS

NARRATOR: During its brief flyby, Mariner 4 gives the first close up glimpses of Mars.

NEWS AUDIO ARCHIVE FOOTAGE: A revelation comparable to Galileo’s first view of the moon through a telescope.

CRATERS 75 MILES ACROSS ARE DISCOVERED

ARCHIVE REPORTER’S VOICE: First of all, there are two eyes, not only in color but also in stereo, and the infrared part of the spectrum.

NARRATOR: Viking is the first to successfully land on Mars.

MISSION CONTROL: Touchdown we have touchdown.

VIKING 1 AND 2 LAND ON MARS WITHOUT A HITCH

ARCHIVE VOICE: Perfect set down.

NARRATOR: But the most surprising revelations come from the rovers, Spirit and Opportunity.

SPIRIT AND OPPORTUNITY

2004

EXPECTED TO LAST ONLY MONTHS

OPPORTUNITY EXPLORES FOR 14 YEARS

DISCOVERS EVIDENCE OF ANCIENT FLOWING WATER

NARRATOR: Over 50 years of Mars exploration has revealed intriguing clues, suggesting Mars has a surprisingly watery past.

ASHWIN VASAVADA: There’s a lot of evidence for ancient flowing water on Mars. For one thing, there’s a lot of rivers that once coursed across the surface that are now dry, today. There’s also evidence for floods that catastrophically scoured the surface.

JOHN GROTZINGER: It’s undeniable that the early history of Mars was much wetter than it is today.

STEVE SQUYRES: The surface of Mars is littered with an uncountable number of little round things. These “blueberries,” as we nicknamed them, are what geologists call “concretions.”

Concretions form, typically, in sedimentary rocks that are soaked with liquid water. And so, what those blueberries told us was that this was a place where the ground was once soaked.

JOHN GROTZINGER: It might not have been as wet as the earth, but it was probably wet enough for life to evolve. What everybody wants to know is whether or not Mars once had life.

NARRATOR: Were conditions on Mars once suitable for life? To find out, a new generation of spacecraft is investigating, led by the most complex mission to the Red Planet ever attempted.

CURIOSITY 2012

ASHWIN VASAVADA: Mars has a unique set of challenges compared to other places we go with spacecraft.

ROVER THE SIZE OF AN S.U.V.

ASHWIN VASAVADA: Mars has an atmosphere, but it’s thin, so, not enough to really slow you down.

SPEED ON ENTRY – 12,000 MPH

ASHWIN VASAVADA: But it is enough to actually burn you up as you’re trying to land. To get Curiosity safely to the surface of Mars, we basically had to pull out every trick in the book.

ONE TON OF ADVANCED ROBOTICS

NARRATOR: At 2,000 pounds, Curiosity is one of the largest and heaviest probes anyone has ever attempted to land in the thin Martian atmosphere.

ASHWIN VASAVADA: We fired rockets, and a jetpack flew the rover down to the surface. We knew it landed safely when we realized that the wheels sensed the ground. At that point, a signal was received, and all of us, sort of, melted in our seats, knowing that we had successfully landed on Mars.

Just a few minutes after landing, we had the first images come back. It’s a thrill to see images of a new world, you know, from eye level for the first time.

NARRATOR: Curiosity touches down in Gale Crater. The remains of an asteroid impact about 100 miles wide, thought to have been home to ancient lakes and rivers.

ASHWIN VASAVADA: As we drove out of our landing site, we came across what looked like an upturned sidewalk, with, like, concrete, kind of breaking apart and pebbles falling out of it. This was a rock that had been cemented together. And when the geologists studied those rounded pebbles, they realized this rock probably was once the bed of a river flowing on Mars, with water, maybe, like, kneedeep.

NARRATOR: To find out if these ancient waters had the basic ingredients for life, or endured long enough to support it, requires careful analysis.

JENNIFER EIGENBRODE: Curiosity is a roving laboratory. We collect samples, by scooping it or by drilling, that allow us to pick apart the story that those things hold.

NARRATOR: Sixty-one days after landing, Curiosity takes the first of many scoops of soil. Analyzing the sand and stone across the crater reveals something surprising: not only is the Martian soil bound with water molecules, but also a small amount of carbon-rich organic material.

JENNIFER EIGENBRODE: Organic matter is actually composed of carbon. It’s carbon molecules put together. And that is a turning point for us. What we found in those rocks is what we expected of natural organic matter. It’s what you would expect to find on Earth. Finding the organic matter is the clue to searching for life.

NARRATOR: And crucially, these ingredients are present for millions of years.

ASHWIN VASAVADA: Really, the central discovery of the mission so far, is that there were lakes that survived for maybe tens of millions of years. And within those lakes, there was fresh water, there were the raw materials that life requires.

NARRATOR: Just beneath the surface, amongst ephemeral droplets of concentrated brine, lie the raw chemical ingredients for life, the final tears of a long lost world.

MARS 4 BILLION YEARS AGO

NARRATOR: For hundreds of millions of years, Mars is a water-world, rich with the building blocks for life. Rains fall, rivers run, and in the northern hemisphere, evidence suggests, water collects in a vast sea, bigger than the Arctic Ocean, that covers a fifth of the Martian surface. The “Red Planet” was once blue.

But it didn’t last.

STEVE SQUYRES: The fascination, to me, about the early, warm, wet Mars, is not what happened. Although that’s an interesting question: why did it dry up?

JOHN GROTZINGER: The billion-dollar question is whether or not Mars actually originated life before all the water was lost.

STEVE SQUYRES: How far along did it get? How far along did the process go, and did it go long enough that life could have taken hold there?

NARRATOR: Today, only one blue planet survives. Seventy percent of Earth’s surface is covered by oceans. Under the waves, up to a million species thrive, while on land, the rains support Earth’s delicate ecosystems, providing a home for complex life to evolve. But our planet hasn’t always been so hospitable.

EARTH

4 BILLION YEARS AGO

NARRATOR: The early earth is unrecognizable compared to the planet we know today.

JENNIFER EIGENBRODE: When Earth first formed, it was this molten body, and it probably had a crust that was forming around the outside, and it was moving around a lot, and it was turning into something rocky.

JOHN GROTZINGER: And then, at the same time that the rocks are forming, we’ve also got gases in the atmosphere, liquid water to form oceans.

NARRATOR: Chemical analyses of our planet’s oldest rocks reveal its atmosphere was choked with carbon dioxide, spewing from myriad active volcanoes, making its newly formed oceans acidic.

STEVE SQUYRES: Early Earth was a very different place from today’s Earth.

JOHN GROTZINGER: If one looked at Earth from another solar system and asked, “is Earth alive?” it would have been hard to tell four-billion years ago.

JENNIFER EIGENBRODE: And then everything changed and chaos ensued.

NARRATOR: Clues as to what happened next can be seen when the moon rises in the night sky above us. Etched into the moon’s surface are vast areas of impact craters and lava fields, traces of a violent past, revealed by the lunar landings.

APOLLO 11 MISSION CONTROL: Two, one...

APOLLO 11 1969

500 MILLION WATCH WORLDWIDE

BETWEEN 1969 AND 1972

6 APOLLO MISSIONS

VISIT 6 DIFFERENT SITES

NARRATOR: Over three years, Apollo astronauts take samples from across the moon’s surface.

COLLECTING 2200 ROCK SAMPLES

NARRATOR: The age of the rocks they collect suggests the majority of the craters form in a narrow window of time, peaking 3.9-billion years ago. And travelling to the far side of the moon, a side we never see from Earth, reveals even more: countless craters, a permanent record of a ferocious bombardment, unleashed throughout the inner solar system, thought to date from the most violent period since the planets themselves formed, known as the “Late Heavy Bombardment.”

JOHN GROTZINGER: This Late Heavy Bombardment turns out to be a critical event in the history, especially of the terrestrial planets.

JENNIFER EIGENBRODE: All of the rocky planets were being hit by other rocks from other places in the solar system.

NARRATOR: Around four-billion years ago, while the outer planets are settling into their orbits, it’s thought they disrupt a cloud of icy objects circling at the edges of the developing solar system, sending many hurtling inwards toward the sun.

JOHN GROTZINGER: And so these fragments and pieces of rock all arrive at about the same time in the inner part of the solar system, to hit the planets like Mercury, Venus, Mars, Earth and the moon.

JENNIFER EIGENBRODE: Imagine meteorites hitting on a regular basis. It caused turmoil on the surface of all those planets.

JOHN GROTZINGER: They basically hit with such energy that they resurface the planets.

MARS

3.9 BILLION YEARS AGO

NARRATOR: As rocky asteroids fragment in Mars’ atmosphere, havoc rains on every corner of the planet. Based on rates of crater formation on the moon, it’s thought at least 50 tons of rock fall for every square meter of Mars’ surface, in a hard rain that lasts tens of millions of years. Over a third of the planet’s crust is resurfaced, as Mars descends into chaos.

EARTH

3.9 BILLION YEARS AGO

NARRATOR: Earth suffers the onslaught just as Mars does. Relentlessly smashed by falling rock, both young planets endure a catastrophic pounding. But just when conditions appear at their least promising on Earth, the raw organic molecules on its surface come together to produce its most precious creation, life.

NICK LANE (University College London): The kind of environment that’s needed for life to start, we need to be converting the first organic molecules to whole cells, and those kind of conditions require a dynamic geological environment. And that kind of environment would have been everywhere on the early Earth.

NARRATOR: The volatile conditions on Earth may be responsible for turning the simple organic molecules already present, into complex organic material capable of replicating itself, D.N.A.

NICK LANE: We don’t know precisely where life started. It could have been an environment like this terrestrial geothermal system. It could have been even delivered from space, perhaps organic molecules delivered into exactly this kind of setting. To me, it seems more likely that it started under the oceans in deep-sea hydrothermal vents.

NARRATOR: Volcanic activity erupting deep in the oceans would create a high-energy system.

NICK LANE: That pressure makes reactions happen faster and more likely to give rise to life.

NARRATOR: And the emergence of life need not be limited to just one planet.

NICK LANE: Life should really start wherever these geologically active conditions are met: where we have a continuous bubbling of gases from in the bowels of the planet or the moon to react with gases in the atmosphere or in the oceans. These conditions are very similar to what we think might have been present on Mars four-billion years ago.

NARRATOR: But how can we be sure that catalysts for life like this existed on Mars that long ago?

MISSION CONTROL ATLAS V: Ignition and liftoff of the Atlas V rocket with M.R.O….

MARS RECONNAISSANCE ORBITER

MISSION CONTROL ATLAS V: …surveying for the deepest insights into the mysterious evolution of Mars.

SENT TO INVESTIGATE MARS’ ANCIENT SEAS

SEARCHING FOR HABITATS WHERE LIFE COULD EVOLVE

NARRATOR: Searching for conditions that could kick start life is NASA’s Mars Reconnaissance Orbiter. Sent to map Mars in intricate detail, M.R.O. sends back more data than all other Mars missions combined.

NASA MARS RECONNAISSANCE ORBITER

LESLIE TAMPPARI (Deputy Project Scientist, Mars Reconnaissance Orbiter): M.R.O. has three cameras on board, the first is the MARCI weather camera. It sees horizon to horizon on every orbit, so it builds up a map of the entire planet every day. So you can see a global weather map, every day, on Mars.

The second camera is the Context Camera. It provides high resolution and it’s covered about 99 percent of the surface.

NARRATOR: M.R.O. has made more than 60,000 orbits, its high-resolution cameras revealing Mars in unprecedented detail, discovering polar avalanches, shifting sand dunes, and what look like seasonal flows of sand or even liquid melt water.

Then in 2017, M.R.O. turns its gaze to some of the Red Planet’s oldest rocks in the Eridania Basin, thought to have once been home to an ancient sea.

ERIDANIA BASIN

3.8 BILLION YEARS AGO

LESLIE TAMPPARI: Eridania Basin is a huge basin in some of the most ancient crust on Mars. It formed about 3.8-billion years ago, and it held more water than 10 times that of the Great Lakes, or three times that of the Caspian Sea on Earth.

NARRATOR: And it’s on this ancient seabed that M.R.O. sees something remarkable: a potential catalyst for life.

LESLIE TAMPPARI: M.R.O. saw a massive 400-meter thick deposit, formed from a mineral that forms in deep-sea hydrothermal environments, such as one that might have undersea vents.

NARRATOR: Analysis shows the deposits are rich with saponite, a mineral found on Earth at hydrothermal vents, suggesting, in the past, Mars not only has had the same ingredients for life as Earth but also an active environment to spark it into action.

LESLIE TAMPPARI: Eridania Basin was an ancient sea, 3.7- to 3.8-billion years ago. And that’s about the same time when life was first emerging on Earth. This might have been a place where life could have existed, because those hydrothermal vents underneath that sea might have created a very conducive environment for life.

JOHN GROTZINGER: These initial conditions in the history of both planets look so similar that it seems reasonable to expect that this could eventually lead to life.

NARRATOR: These actively fertile conditions are thought to survive in places like the Eridania Basin, for hundreds of millions of years, with Mars, like Earth, rich with the potential for life. But then, 3.7-billion years ago, something happens that transforms prospects for life on Mars forever.

Analysis of the ancient Martian surface reveals a dramatic change.

STEVE SQUYRES: Mars underwent a fairly substantial transformation in its climate. The climate got colder. What liquid water there was either soaked into the ground and froze or froze at the surface. A lot of it, ultimately, would get transported to the poles, where it forms these big thick icecaps that we see today.

NARRATOR: At the same time as the temperature plummets, Mars becomes more volcanically active, leading to catastrophic flooding, with water raging for hundreds of miles, until, in a place known as Echus Chasma, it plunges over cliffs two-and-a-half-miles high, creating the largest waterfall the solar system has ever seen, cascading into a spectacular canyon six miles wide and 60 miles long.

ECHUS CHASMA

NARRATOR: Once the floods subside, the water disappears, the only trace it ever existed etched into the planet’s surface.

So, what causes this dramatic change in climate? That’s being investigated by NASA’s most active Mars orbiter.

MARS ATMOSPHERE AND VOLATILE EVOLUTION MISSION

MISSION CONTROL MARS ATMOSPHERE AND VOLATILE EVOLUTION MISSION: T-ten, nine, eight, seven, six, five, four, three, two, one. Main engines start, ignition and liftoff of the Atlas V with MAVEN, looking for clues about the evolution of Mars through its atmosphere.

NARRATOR: In September, 2014, NASA’s MAVEN probe is on its final approach to the Red Planet. Its mission: to understand the processes that transformed Mars.

BRUCE JAKOSKY (Principle Investigator, MAVEN): We know that the Mars climate has changed through time. The geological evidence tells us there was lots of water early on and that it’s been cold and dry in the last couple of billion years.

MAVEN was sent there to understand what processes drove this climate change.

MAVEN MISSION CONTROL: Based on observed navigation data, congratulations.

BRUCE JAKOSKY: Maven flies in an elliptical orbit around the planet. At its lowest point, it’s only 150 kilometers above the surface; at its highest point, it’s over 6,000 kilometers. That means that on every orbit, we’re able to measure the full profile of the entire upper atmosphere.

The previous missions we’ve sent had cameras to look at the geology of the surface or the behavior of the clouds and dust in the lower atmosphere. We’re making measurements in the upper atmosphere, where we’re more interested in the behavior of atoms and molecules, so our instruments are focused on measurements of those.

NARRATOR: MAVEN carries an array of instruments designed to measure the behavior of atoms and molecules in Mars’ atmosphere.

BRUCE JAKOSKY: From the measurements that MAVEN has made, now over an entire Martian year, we’ve confirmed that gas is being lost to space today, out of the atmosphere. And it’s being lost at a rate of about two to three kilograms every second.

NARRATOR: By measuring the gas being stripped from its atmosphere, MAVEN is witnessing the process that transformed Mars’ climate over three-and-a-half-billion years ago.

BRUCE JAKOSKY: We think that this stripping of the atmosphere over time has been responsible for the change in climate which Mars has suffered.

NARRATOR: Mars lost much of its water and the atmosphere that insulated it from the cold of space, leaving it frozen and dry. So what was it that sent Mars down such a different path from Earth?

The sun’s outer corona burns at a scorching 1,000,000 degrees. It releases a barrage of charged particles that travel at hundreds of miles a second, the solar wind. This onslaught would strip away our atmosphere, but for the powerful magnetic field that protects us.

STEVE SQUYRES: Solar wind is this stream of charged particles that come streaming out from the sun. And at Earth, which has a powerful magnetic field, when those charged particles begin to get close to Earth, they get diverted around Earth by interactions with that magnetic field.

JENNIFER EIGENBRODE: That protection keeps solar wind and other ionizing radiation off of the surface. So, on Earth, where we have this really great magnetic field, we are nice, safe and sound, inside the shell of that, protected from all that radiation.

STEVE SQUYRES: The magnetic field of Earth effectively forms a protective bubble around the earth’s atmosphere.

NARRATOR: And when the sun dips below the horizon, there are times when the earth’s protective force field is visible. The aurora is a stunning display of the earth’s magnetic field in action. It’s best seen at the poles, but across Earth, it’s protecting our atmosphere and all life on our planet. This vital protective shield is generated deep within.

STEVE SQUYRES: The way a magnetic field is generated inside a planet is when you have convective motion in a fluid that is capable of conducting electricity. And in the earth, that electrically-conducting fluid is liquid iron. And the molten portion of the earth’s core is a place where these motions take place, and it can set up a magnetic field.

NARRATOR: Just like Earth, Mars once had a molten metallic core generating a magnetic field around the planet. Auroras danced above Mars’ poles, protecting its atmosphere and seas below.

But the field didn’t last.

STEVE SQUYRES: In the oldest rocks on Mars, you see evidence of a once powerful magnetic field. You get to the younger rocks, the rocks that are three-billion, two-billion, one-billion years old, no evidence of a magnetic field, whatsoever. And there is no intrinsic magnetic field on Mars today.

JENNIFER EIGENBRODE: This invisible magnetic field around the planet, something we can’t see, it’s like this layer of protection around the planet, disappeared.

NARRATOR: Half-a-billion years after it formed, Mars’ magnetic field dies out. The bright auroras above its poles slowly fade away, as the shield that protects the planet shuts down for good.

JOHN GROTZINGER: Once it stops, then what happens is all the atmospheric components, things like hydrogen and oxygen that make up water, they get stripped away, because you don’t have the shield, the magnetic shield anymore. So, the high energy particles that come in from the sun and from outer space, they begin to strip away the components that make up water.

NARRATOR: Without its magnetic field to protect it, Mars’ atmosphere and then water, slip away into space.

So, why did Mars lose its protective shield? What happened deep beneath its surface that stopped Mars from developing like Earth? The answer lies at the very beginning of Mars’ story, at its very creation.

4.6 BILLION YEARS AGO

NARRATOR: Four-point-six-billion years ago, when the planets were forming from the dust cloud circling the sun, early differences between Mars and Earth set the young planets on very different paths.

Crucially, Mars forms farther from the sun, where there is simply less rocky material to build a planet.

JOHN GROTZINGER: Mars is different, because it’s not just further out, it’s actually much smaller. If a planet gets to be too small, it just freezes all the way through.

JENNIFER EIGENBRODE: Because Mars is so much smaller, there’s less thermal energy coming from the interior of the planet. The planet is fundamentally different from the interior out, and that is what separates Mars from Earth.

NARRATOR: It’s this critical size difference that seals Mars’ fate and shapes its surprising story.

Four-and-a-half-billion years ago, two young planets are born. Initially inhospitable and toxic, both young planets develop into warm watery worlds. They both survive the violence of the Late Heavy Bombardment, emerging as mature planets, primed with all the ingredients for life to begin. But while Mars appears to be thriving, deep in its cooling core, the planet is dying. Its once great ocean is lost to space. One by one, its volcanoes go quiet. As the lava turns to stone, all hope of recovery is extinguished.

Today, Mars traces a lonely path through the solar system, rusted and gathering dust, but this is far from the end of what we hope to discover.

ESA EXOMARS

MARS 2020

LOOKING FOR NEW LIFEFORMS

COLLECTING SAMPLES TO RETURN TO EARTH

PREPARING FOR CREWED MISSIONS

NASA ORION

NARRATOR: The next generation of spacecraft will soon be on their way, with missions like European Space Agency’s ExoMars and Mars 2020 searching for signs of life, and NASA’s Orion, currently undergoing advanced testing, NASA’s first step towards sending humans to Mars.

BUILT TO CARRY A CREW OF FOUR

STEVE SQUYRES: My hopes for the future: eventually there’s boot prints on the surface, you know, humans on the surface doing what humans do: explore.

ASHWIN VASAVADA: Humans are going to go to Mars. I can’t wait to see someone else, not virtually explore Mars, but really explore Mars, as a human being walking on the surface.

NARRATOR: Future generations will be able to look closer than ever before for evidence of life.

JENNIFER EIGENBRODE: So, the next step is to search for life on Mars. We’re probably going to bring samples home. We’ll study them here, and we’ll learn all sorts of things about ancient Mars and even modern Mars.

NARRATOR: And if we do find life on Mars, the consequences will be profound.

STEVE SQUYRES: If you could show that life independently took hold, independently, on two different worlds, just in this one solar system, then when you consider the multitude of planetary systems that we now know are out there, it takes no great leap of imagination, faith or anything else to believe that life could be a universal phenomenon.

It’s a situation where two is a much bigger number than one.

JOHN GROTZINGER: I think, if one was to ever discover life anywhere outside of Earth, it opens up the possibility that the universe is full of life, because if you find just one example in our solar system, now you imagine all the solar systems that have been discovered, that we call “exoplanets,” and then you multiply these things, and it must mean that life is everywhere.

ASHWIN VASAVADA: I often wonder how the world would react if we found life on Mars. For me, personally, it almost feels like we’re reaching the point where it would be more surprising not to find life. I think it still would shock all of us, and we’d be amazed that such a discovery was made. But I’ve personally come to think that life must be present all over the universe and maybe even on a planet as close as Mars.

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A BBC Studios Production with NOVA and WGBH Boston for PBS [logo] and BBC [logo]co-produced by Tencent Penguin Pictures and The Open University.

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This program was produced by WGBH, which is solely responsible for its content. Some funders of NOVA also fund basic science research. Experts featured in this film may have received support from funders of this program.

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Created by Lola Post Production/© BBC Studios

Participants

Jennifer Eigenbrode, John Grotzinger, Bruce Jakosky, Nick Lane, Steve Squyres, Leslie Tamppari, Ashwin Vasavada

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