Scientists on the hunt for extraterrestrial life suspect that it might exist in the Solar System. Using the latest discoveries, experts might at last confirm that our neighbors might harbor alien life.
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LearningTranscript
00:05Though we dream of the possibility of life in the distant universe,
00:11we assume that we are the only life in our solar system.
00:16But is life truly exclusive to our planet?
00:22Thanks to the latest extraordinary advances in astronomy,
00:25it appears that we are closer than ever to answering that question.
00:30A new crop of space probes and sophisticated telescopes
00:34is scanning our solar neighborhood, looking for answers.
00:38And so far, things are looking up.
00:43One of the big triumphs of astronomy in the last two decades
00:47is to show the majority of stars have planets.
00:49There are planets all over the place.
00:51There are more planets than stars.
00:53It's a game changer.
00:55It changes what we think about the possibility for life somewhere else.
01:01We may find some form of life in the strange methane lakes of Titan,
01:07in the ocean hidden under the mysterious icy surface of Europa,
01:12in the gigantic geysers of Enceladus,
01:17or in the desert plains of Mars.
01:21The second genesis within the same solar system implies the origin of life is a likely event.
01:27Is it only a matter of time before we discover life in outer space?
01:48Life.
01:49An unbelievably perfect combination of elements,
01:53able to create living matter.
01:59possibly the biggest mystery of nature.
02:09A combination of matter that shows certain attributes that include responsiveness,
02:15growth, metabolism, energy transformation, and reproduction.
02:22We don't yet know exactly what life is.
02:25We don't have a working definition.
02:26Probably my favorite definition is that life is some sort of chemical entity
02:30that is self-enclosed and is capable of Darwinian evolution by natural selection.
02:36Some studies state that life may have begun on Earth as early as 4.1 billion years ago.
02:44That is still only slightly younger than Earth.
02:49A question arises immediately.
02:51Is life an exclusive phenomenon of our Earth?
02:55There is no easy answer to this question.
03:05The chemistry of life began shortly after the Big Bang, 13.8 billion years ago.
03:11During a habitable period when the universe was only 10 to 17 million years old.
03:21Life may have emerged independently at many places throughout the universe.
03:28Or life may have formed less frequently, then spread by meteoroids or comets,
03:36between habitable planets in a process called panspermia.
03:46In any case, complex organic molecules may have formed in the protoplanetary disk of dust grains
03:54surrounding the Sun before the formation of Earth.
04:00According to these hypotheses, the processes leading to life may occur outside Earth
04:07on several planets and moons of the solar system.
04:15Since ancient times, humankind asked itself if we are alone in the universe,
04:20and if there is life beyond Earth.
04:25Those questions may not be easily answered.
04:29However, they have always fascinated us.
04:33Astronomers have been interested in the question of life beyond Earth for a very long time.
04:38We can trace back through the ancient Greeks and Romans and Chinese writings speculation about life beyond Earth.
04:49The first goal in our search for life is to establish the conditions that will support it.
05:00A source of energy, such as from a nearby star, is needed to drive endothermic or energy-absorbing reactions.
05:08Raw materials, predominantly carbon, build and form organic molecules.
05:16So the building blocks of life on Earth, and we know that there are carbon, hydrogen, oxygen, nitrogen, and others,
05:27they are what we are looking on other planets to look for life as we know it.
05:33These building blocks for life, at least as we understand it, are ubiquitous.
05:42Also indispensable is the presence of a liquid, or very dense gas,
05:47that enables biochemical reactions to occur quickly and stably.
05:54Liquid water, the life-sustaining universal solvent, at least on Earth, requires certain atmospheric composition and temperatures.
06:08In order to have a habitable environment, you need three things.
06:12You need liquid water, and you need organic material, and you need energy.
06:18And there are a number of places in the solar system where all three of those things are thought to
06:23exist.
06:27If we know the key conditions for supporting life,
06:31the question is then,
06:34how many planets or moons in our solar system meet these conditions?
06:43Considering that one of the key prerequisites for extraterrestrial life is the existence of liquid water,
06:49there are three candidates in our solar system that have liquid water on their surface.
06:56The planet Mars,
07:00Jupiter's moon Europa,
07:04and Saturn's moon Enceladus.
07:11Of all 160 or so planets and moons in the solar system,
07:16Mars has so far received the most interest from astrobiologists.
07:21There are many signs that show that very early in its history,
07:25Mars was much like Earth,
07:28with large areas of liquid water,
07:31a thick atmosphere,
07:34ample sources of energy for life,
07:37and a good inventory of organic molecules.
07:42In fact, what I like to say when I compare the two planets is that you don't have to invent
07:46words to describe Mars.
07:49You have mountains, you have canyons, you have polar caps, you have dunes.
07:57There is evidence that Mars had a warmer and wetter past.
08:02Dried up riverbeds.
08:06Vast canyons blasted out by epic floods.
08:11Valleys carved by raging rivers.
08:16Polar ice caps.
08:19Volcanoes.
08:21And minerals that form in the presence of water.
08:25Have all been found.
08:29There's a lot of evidence for liquid water earlier in the planet's history,
08:33much earlier, about four billion years ago,
08:35and perhaps some transient water in the time since four billion years ago.
08:41But the evidence indicates that all water disappeared from the surface billions of years ago,
08:48as Mars cooled down and lost its atmosphere.
08:54Did life ever get a foothold on the planet?
09:12Scientists looking for life on Mars start by examining evidence from a planet much closer.
09:18Earth.
09:20As we are looking for evidence for ancient life on Mars,
09:26some people think that actually we already had some evidence of that life landing on our own planet.
09:33And the best example of that is the Alan Hill meteorite.
09:40We had a piece of Mars here in the lab.
09:46We still have it.
09:48Alan Hill's 84001.
09:51A rock that was chipped off Mars by an impact millions of years ago,
09:57wound around in space, landed on the Earth in the Antarctic ice sheets.
10:03And during the 1984 spring collection season, as that ice was melting and those black rocks were picked up in
10:13the melt pools,
10:14we realized by the gases that are included in that piece of rock that that's a piece of Mars.
10:22And we took it apart at microscopic scales.
10:27And we had a big scientific controversy because there were scientists that were claiming features in that rock could only
10:35have been produced by biology.
10:37And other scientists saying, nope, you can get that with geology.
10:48The search for life on the red planet started decades ago.
10:55In 1976, a search for microbial life on the red planet was performed for the first time ever.
11:05Two decades later in 1997, the Pathfinder mission took a new step forward in this search for life adventure.
11:12It found magnesium, aluminum, iron, and phosphate in Martian rocks, which are all possible life-supporting materials.
11:24In 2008, the Phoenix spacecraft explored Mars' North Pole.
11:36After digging a few inches, it found a white material that evaporated several days later.
11:46The analysis of that material revealed it was water ice.
11:54Satellites scanned both polar caps and found that there was a lot of water ice under a layer of frozen
12:00carbon dioxide.
12:03If all that ice ever melted, an 80-foot deep ocean would cover the whole planet.
12:14The same satellites also discovered that there was ice buried everywhere beneath the desert plains.
12:24This was a shocking discovery.
12:28Mars had huge amounts of water ice everywhere.
12:32But could life exist in the buried ice itself?
12:40We now know that there are extremophile microorganisms able to live in similar environments in the dry valleys in the
12:47Antarctic, here on Earth.
12:50Currently, Mars is very dry and very cold.
12:54It's like some regions in Antarctica today.
12:58And it's kind of like a very cold desert.
13:01So, liquid water would not be stable.
13:05For example, if you opened up a container of water, it would immediately evaporate because it's so dry.
13:12Buried ice was found under a layer of dry dirt, as also happens on Mars.
13:18At the point where the dirt met the ice, there was a thin film of liquid water where extremophiles thrived
13:25just for a short time.
13:30These microorganisms remain frozen and dormant most of the year, and they only flourish for a few warm weeks during
13:38the summer.
13:40Today, Mars could still live at that.
13:43Some that favored by the presence of thin films of water, or maybe more liquid water, because the deeper you
13:50go, the more the chance that water could be liquid.
13:55During the Martian summer, it's common to reach 70 degrees Fahrenheit of the equator.
14:01So the buried ice might melt and create similar conditions to those found in the Antarctic dry valleys.
14:08Any microbes that might have been there, they're probably living within the rocks or under rock coatings.
14:13So that's one of the analog sites that my group's been investigating is microbes that are living underneath the surface,
14:21because that might be viable for Mars as well.
14:25A future mission could eventually prove whether this hypothesis is true or not.
14:34But there is another possibility that liquid subsurface water exists on Mars.
14:44Mars' huge volcanoes such as Olympus Mons could contribute internal heat to sustained subsurface water.
14:52This would imply that hydrothermal vents could exist on Mars as well, and therefore it might also be possible that
15:00extremophiles, similar to the ones that thrive in the terrestrial hydrothermal vents, exist on Mars.
15:11On September 2015, NASA's Mars Reconnaissance Orbiter made an incredible discovery.
15:21This spacecraft provided the strongest evidence yet that liquid water flows intermittently on present-day Mars.
15:32It's not pure transparent water, it's very briny water, very salty water, which allows it to remain stable for a
15:41little while at the surface because the pressure at the surface of Mars is very, very small.
15:48Using an imaging spectrometer, researchers detected signatures of hydrated minerals on slopes where mysterious streaks were seen on the red
15:58planet.
16:00They darken and appear to flow down steep slopes during warm seasons and then fade in cooler seasons.
16:09This finding proved what anyone could have imagined.
16:13On Mars' present-day surface, there is liquid water.
16:19Maybe in some of those ephemeral streams of liquid water, microbial life has managed to arise.
16:31We will have to wait for future rovers and explorers to confirm this hypothesis.
16:40In the meantime, there is another body in our solar system that could hold life, but it's not a planet.
17:01Much further away than Mars, there is another unique world that might harbor life, Europa.
17:10Europa is one of the four largest moons of Jupiter.
17:13It's slightly smaller than our moon, and its icy surface is negative 250 degrees Fahrenheit.
17:22Virtually everything we know about Europa is thanks to NASA's unmanned space probe Galileo, which passed by Europa 12 times.
17:36These were the first images it captured.
17:40It is covered by a smooth layer of water ice.
17:43In fact, it has the smoothest surface of any known solid object in the solar system.
17:50The surface of Europa is unique in the solar system.
17:54It has very few craters, which tells us that the surface is being reprocessed frequently.
18:02Some parts of its surface show blocks of ice that are separated, but seem to fit together like a puzzle.
18:08These icebergs could have been shifted by slushy or liquid water beneath.
18:14These cracks probably may extend all the way down to the ocean or at some point, so you could get
18:21some percolation of water.
18:24This peculiar landscape is very similar to sea ice on Earth.
18:33Galileo was able to detect that all of those things together add up to our picture of how we now
18:37know that Europa has a liquid ocean under its surface.
18:44In 1996, the Galileo spacecraft detected a magnetic field on the planet's surface, indicating that there must be some electrical
18:53conduction likely to derive from a salty ocean.
18:57It could be 60 miles deep.
19:02The studies and observations, measurements that have been made in the past decades, seems to be converging pretty clearly with
19:14the presence of an ocean under the surface of the ice.
19:20So there we have the first key ingredient for life, liquid water.
19:27How can water remain liquid at temperatures of negative 300 degrees Fahrenheit?
19:35Some sort of mysterious internal heat must be melting the icy crust.
19:42And Jupiter is the culprit.
19:46Scientists propose that it's due to the tidal heating from the friction due to Europa's eccentric orbit around Jupiter.
19:54The ice on the surface of Europa has been cracked.
19:58It's not completely sealed.
20:00You can see because of gravitational pull and pull, there is this tug of war as Europa is moving around
20:08Jupiter.
20:09You can imagine that all this friction is creating lots of energy, lots of heat.
20:15And then we have good reasons to think that there are hydrothermal systems, which means that you have, you know,
20:23water being heated by this process.
20:29Volcanoes deep down may harbor hydrothermal vents that provide an energy source to heat and maintain liquid water.
20:37So we have two of the three conditions for life.
20:41A liquid, in this case liquid water, and a source of energy, that interior heat.
20:49We would just need some organic compound, and the chances of life arising would skyrocket.
20:59The Galileo spacecraft observed that Europa's ice contains carbon dioxide.
21:04When this carbon dioxide is strongly impacted by Jupiter's radiation, it can produce simple organic molecules, such as formaldehyde, that
21:15are steps towards life.
21:19The aforementioned tides on Europa could also mix life-supporting substances together in the ocean, but nothing has been proven
21:28yet.
21:33In 2013, NASA reported a surprising discovery on the icy crust of Europa.
21:40Some clay-like materials, specifically, phylosilicates, were detected.
21:47Phylosilicate just means phylo-like layered silicate, and these are a fancy name for clays.
21:54And clays are a kind of mineral that forms in a lot of water.
21:58And on Earth, there are some theories that these clays were some of the original minerals that were present when
22:04life was evolving.
22:07According to some hypotheses, the presence of these organic-associated minerals may have been the result of a collision with
22:14an asteroid or comet.
22:22With liquid water, an energy source, and the necessary chemical building blocks, perhaps delivered by comets or asteroids,
22:30Europa opens up the possibility that life could exist in places never imagined.
22:4412,000 feet beneath the Arctic ice sheets.
22:47In complete darkness, there are hydrothermal vents that spew out superheated water with lots of toxic chemicals.
22:58Scientists think vents like this could also exist on Europa's ocean floors.
23:04We think that the potential source of energy for an ocean in Europa will be the volcanic activity.
23:12We have recently discovered that clustered around the vents, there are extremophile microorganisms that cover miles of the Arctic sea
23:20floor.
23:22The discovery of life there really raises the possibility of life on Europa.
23:30Probably, uh, Europa might be the best, the best candidate for us to find, uh, extent life.
23:42The challenge now is to prove that life has been able to thrive in such a bizarre environment.
23:49NASA and the ESA have planned two different missions to Europa that will investigate its habitability in the next few
23:57years.
23:58In 2015, NASA approved a new mission to go to Europa and investigate, uh, its environment and particularly to look
24:07for habitability.
24:10NASA's Europa multiple flyby mission is a spacecraft that will be launched in the 2020s.
24:16The spacecraft will be a highly capable, radiation-tolerant probe that will perform repeated close flybys of the icy moon.
24:27I will also be looking under the surface to learn more about the structure of the ice shell and the
24:34structure of the ocean underneath the shell, uh, using radar and magnetic field detectors and other instruments.
24:42The ESA is developing another mission, the Jupiter Icy Moon Explorer, the so-called JUICE mission that is planned for
24:53launch in 2022 and arrival at Jupiter in 2030.
24:57This spacecraft will spend at least three years making detailed observations, not just of Europa, but also of the giant
25:06gaseous planet Jupiter and two of its largest moons, Ganymede and Callisto.
25:15We will have to wait till the next decade to confirm whether or not there is life on Europa.
25:23But could another moon in our solar system have similar conditions for life?
25:43Europa isn't the only intriguing place this far out in the solar system.
25:50Could similar conditions exist on other moons orbiting other planets even further away from the Sun?
26:00Orbiting Saturn, there is a small, mysterious moon that is totally different from the rest of its more than 60
26:07moons.
26:09This tiny, icy moon, only 300 miles across, is Enceladus.
26:16In the last few years, this tiny moon has become the main goal for exobiology as it has revealed some
26:24extraordinary conditions for harboring life.
26:27Most of what we know about Enceladus is thanks to a mission called Cassini.
26:33It's a mission that has been going on for many years.
26:37It's an orbiter that has been studying the entire Saturn system and its different moons, but it's been paying close
26:44attention to Enceladus.
26:47The Cassini mission offered us a close-up of this remote world for the first time ever.
26:58These were the first images it took.
27:01The surface is white and glittering, and it is carved with fissures, crests, and cracks.
27:09At the South Pole, Cassini made a surprising discovery.
27:15It photographed some strange, large cracks seen here in blue.
27:21Four parallel fissures, scientists named the Tiger Stripes.
27:28They are 75 miles long and hundreds of feet deep.
27:33They are similar to fault lines on Earth.
27:39After several flybys, Cassini's thermal radar revealed something unexpected.
27:47The Tiger Stripes should be colder than the rest of the moon, as they were in the South Pole.
27:53However, they were radiating heat.
27:57The fissures were at negative 120 degrees Fahrenheit, which was more than 270 degrees warmer than the rest of the
28:06moon.
28:09It's definitely a place where we see evidence that something profound is happening in terms of potential for habitable environment.
28:19But the most shocking finding was still to come.
28:26When Cassini was reoriented, it captured a shocking image.
28:31Vast jets of ice were erupting into space.
28:37The camera was able to image plumes of water vapor and ice crystals coming off the South Pole of Enceladus.
28:49These actual images showed the plumes were ejecting ice particles hundreds of miles out from the Tiger Stripes.
28:57Those materials are being ejected through fractures on the surface of the moon, which seem to be connecting the surface
29:03with the interior.
29:05However, how can this small moon generate so much heat as to be able to maintain such geothermal activity?
29:15Scientists believe that Enceladus might have an internal energy source like Europa.
29:21When it orbits the massive Saturn, friction from gravitational processes causes it to heat up, melting ice in the moon's
29:30interior in the same way as on Europa.
29:34These jets were giant geysers of water that erupted from its icy surface, much like those in geologic hotspots on
29:43Earth.
29:46Cassini actually has a detector that can fly through the plume, pick up some of the particles and analyze them
29:51chemically.
29:52And when that detector did its work, it found that some of the particles are salty.
29:57And the only way to get salt incorporated into a particle is to have it evaporating directly off of liquid.
30:05So that was yet another hint that Enceladus has liquid under the surface from which these plumes are emanating.
30:14But could it prove that under the icy crust of Enceladus existed a subsurface ocean like on Europa?
30:23We needed even more evidence.
30:25The next piece of evidence was from Cassini flying past Enceladus and just carefully analyzing its trajectory as it flew
30:35past Enceladus
30:36to directly measure how Enceladus' gravity was pulling on the spacecraft.
30:41And when that analysis was done, it found a density anomaly under the entire South Pole,
30:47indicating that you have a regional sea of water from which these plumes are emanating.
30:55These jets might be connected to active hydrothermal vents at a subsurface water ocean floor,
31:02where the moon's ocean meets the underlying rock, a prime potential habitat for life.
31:11But there still wasn't anything that could prove life existed underneath that icy crust.
31:19That's why it was decided that Cassini should fly through these jets and collect particles.
31:29The probe's spectrometers detected something really exciting.
31:34They found in the jets the basic chemical building blocks of life.
31:39So Enceladus is fascinating because, as far as we can tell, it contains the three basic ingredients for life.
31:48Liquid water, nutrients and organics.
31:53But does this strange and alien world actually support life?
31:59The geysers could provide easy access for sampling the moon's subsurface ocean.
32:04And if there is microbial life in it, ice particles from the sea could contain the evidence astrobiologists need to
32:13identify them.
32:15There are two exploration missions proposed by NASA to Enceladus in the near future that would try to find evidence
32:23of life in the tiny icy moon.
32:26The first one is the Journey to Enceladus and Titan mission.
32:31This is an astrobiology mission concept that will assess the habitability potential of Enceladus and Titan, moons of Saturn.
32:42The second mission waiting for approval and financing is the Life Investigation for Enceladus.
32:51This proposed mission would capture icy particles from Saturn's moon, Enceladus, and return them to Earth, where they could be
32:59studied in detail for signs of life, such as biomolecules.
33:05It's relatively simple, technologically speaking, to send an orbiter to Enceladus that can capture those icy particles in the plume
33:14and analyze them in situ,
33:15or bring them back to Earth for detailed analysis in the laboratory.
33:20Unfortunately, neither of these missions have been approved yet.
33:24So we will still have to wait to unveil whether or not there is life on this tiny enthralling moon
33:31of Saturn.
33:32Though we haven't yet found life outside Earth, there is one more candidate for life in the solar system.
33:40Titan.
33:53Close to Enceladus, there is the last of the great candidates for life in the solar system, Titan.
34:02Titan is the largest moon of Saturn.
34:05It is one of the largest moons in the solar system, and it is also the only moon that is
34:12known to have a thick atmosphere.
34:15Data from the Cassini-Huygens mission, which flew by Titan in 2004, demonstrated the existence of hydrocarbon lakes.
34:25Titan is a fascinating world.
34:28It's the most alien place in the solar system, so to speak.
34:33Because in fact, other than the Earth is the only place we know of that has seas of liquid on
34:39its surface, those seas are not made of water.
34:44In these seas and lakes, there are no waves, as the liquid is liquid methane and ethane, which is much
34:51less dense than water.
34:55These two hydrocarbons on Earth are volatile gases.
35:01But on Titan's negative 300 Fahrenheit degree temperature, they are liquid.
35:09Titan has a very similar landscape to Earth.
35:12There are seas, lakes, smoothed rocks on the riverbeds, mountains, valleys, canyons.
35:19But these mountains and pebbles are not made by any rock like on Earth.
35:24They are made of water ice.
35:27So frozen due to the negative 300 degree temperature on Titan's chilly surface, that it behaves like rock.
35:38Cassini's radar images showed that on Titan, liquid methane forms clouds, thunderstorms, and even falls as rain.
35:47Methane in the atmosphere also plays a role similar to water in the atmosphere.
35:52On Earth, you have a water cycle.
35:54On Titan, methane plays a very similar role.
35:57It falls to the surface as rain or mist.
36:01We do see channels and rivers where methane is flowing across the surface and doing geological work like we would
36:11see water do on the surface of the Earth.
36:13Liquid methane has a cycle very similar to Earth's water cycle.
36:18The question is, could it behave like water on Earth, as liquid that allows organic molecules to dissolve and interact?
36:27There is no easy answer to this.
36:31Titan's atmosphere also contains many organic gases such as methane, ethane, and hydrocarbons, and possesses conditions that resemble those of
36:42early Earth 4 billion years ago that allowed life to develop.
36:49In many ways, the atmosphere of Titan looks like a young Earth in the fridge, much colder, much colder.
36:58But prebiotic chemistry, the same processes are there.
37:01What we don't know is whether these prebiotic processes are turning into something that is biological in nature at the
37:11surface of Titan or in the subsurface.
37:13However, liquid methane and ethane are much colder than liquid water by some 400 degrees, and biochemical reactions would occur
37:24at painstakingly slow rates.
37:28These compounds are far less capable as solvents compared to water, and therefore, much less life-inducing.
37:38Water is also missing from the picture due to freezing temperatures of negative 300 degrees Fahrenheit.
37:47Several experiments have shown that with an atmosphere similar to that of Titan and the addition of UV radiation, complex
37:55molecules and polymer substances like tholins can be generated.
38:00Substances that could be considered a sort of precursor to life.
38:04What weirdo chemistry, physics, biology could be, people are trying to think in terms of what could be a biology
38:15based on methane.
38:17That's not the best, apparently, when it comes to provide a structure for biochemistry.
38:25The conclusion is that Titan is a world rich in organic matter, with a methane cycle comparable in atmospherical and
38:33geological processes to Earth's water cycle that is really likely to harbor life.
38:41Titan may harbor life, but how exactly will we get there to find out?
39:00In the last years, NASA and the ESA have combined efforts to develop an unmanned space mission that could finally
39:08unveil all of Titan's mysteries.
39:11But none of them have been approved yet.
39:14One of the most exciting missions proposed to unveil the secrets of the methane and ethane lakes of Titan is
39:21NASA's Titan submarine.
39:23This submarine would explore the depths of the Kraken Mare, the largest known body of liquid on the surface.
39:31This mission would be designed to measure the organic constituents on Titan and would have performed the first nautical exploration
39:39of an extraterrestrial sea,
39:41analyze its nature and possibly observe its shoreline.
39:46As the other proposed mission to Titan, this Titan submarine mission hasn't been given the green light yet.
39:52There's lots of really fun options for exploring Titan, but NASA has not actually selected one of these options.
40:00Therefore, to date, there are no confirmed space missions to Titan in the coming years.
40:06But everything could change if a shocking discovery is made in the near future.
40:13Whether or not any of these potential space missions finally reveal the existence of life on Mars, Europa, Enceladus or
40:22Titan, is an unknown.
40:27But what we do know is that now we are much closer than ever to finally finding an answer to
40:33the question of whether there is life beyond Earth.
40:4350 years ago, the era of robotic exploration of our solar system was just beginning.
40:52In July 1965, the Mariner 4 probe sent the first close-up images of Mars.
41:02Those blurred images showed that Mars did not have vegetation, much less canals criss-crossing the planet as envisioned by
41:11earlier generations of astronomers.
41:15At that time, the most widespread opinion was that Mars was not just the red planet, but also the dead
41:23planet.
41:24With the chances for life of any kind being considered infinitesimal.
41:33Things have radically changed since 1965, thanks to the extraordinary advances of technology that have let us use more and
41:42more sophisticated space probes to explore our neighbors in the solar system.
41:49Three vital factors, energy, liquids, and chemical building blocks are more widespread than has ever been realized.
42:02Now it is not so unlikely to find life beyond Earth in our solar system.
42:07We can't deny that such a huge discovery, even if it were just microbial life, would be really shocking for
42:15mankind.
42:16As it would imply the first step toward believing that we may not be totally alone in the universe.
42:25Last time one, a mission goes by realizing the pushback.
42:28But, that's a good idea.
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