Universo Exoplanetas, la búsqueda de un nuevo hogar [Documental HD]
Hace décadas, no conocíamos ningún planeta más allá de nuestro sistema solar. No teníamos la tecnología para detectarlos. Al mismo tiempo que prosigue la exploración del sistema solar, ha comenzado la búsqueda de mundos que se encuentran más allá
Transcript
00:00In this precise moment, on a planet far, far away,
00:29in a galaxy far, far away,
00:35in a galaxy far, far away,
00:41in a galaxy far, far away,
00:48the dawn gives rise to a new day.
00:52In a galaxy far, far away,
00:59in a galaxy far, far away,
01:05But will there be extraterrestrial eyes that can enjoy it?
01:09In a galaxy far, far away,
01:16in a galaxy far, far away,
01:22Or will it go unnoticed?
01:29Maybe it's like any other lost moment in an immense and sterile universe.
01:42We keep looking for the answer.
01:54Magnificent desolation.
01:56A wonderful view.
01:58System ready.
02:12The Milky Way.
02:26Hundreds of thousands of millions of stars.
02:29Distributed in a space of thousands of light years.
02:40Among them, the Sun.
02:49With eight planets orbiting around it.
02:56Among them, our home.
03:00Until recently, they were the only known worlds,
03:05the only planets we could explore to find signs of life outside the Earth.
03:11When I first started in astronomy, in the 1970s,
03:25we didn't know any planets beyond our solar system.
03:28We didn't have the technology to detect them, even if they did exist.
03:32Our neighborhood was the only place we could look for life.
03:38So we began our search in our closest neighborhood.
03:50In recent decades, we have launched several missions to explore the planets of our solar system.
04:02Also to some of its moons.
04:07But until now, although we continue to search,
04:10we have not found any signs of life in any of those worlds.
04:25The Earth remains something unique.
04:29The Earth remains something unique.
04:37The only planet with life in the solar system.
04:50As we continue to explore the solar system,
04:54the search for worlds beyond our domain has begun.
05:03The wonderful thing about astronomy is that as we develop better technologies
05:08and accumulate more and more knowledge about our universe,
05:12we turn more and more into worlds.
05:18For example, we've known for a long time that Mars is a planet.
05:24But tonight, beyond Mars, we see a constellation called Pegasus.
05:31This is the square of Pegasus.
05:34And we know that around there is a star called 51 Pegasi,
05:39which has a planet orbiting around it,
05:43a gas giant the size of Jupiter,
05:46which revolves every four days around that faint point of light.
05:51It is wonderful to think that throughout my adult life,
05:56in the last 25 years,
05:58we've gone from a universe in which there were no planets outside our solar system
06:04to a universe that we know is full of places where we can search for life.
06:21In the last three decades,
06:23some of the Earth's most powerful telescopes have joined the search.
06:34To the hunt for unimaginably distant planets.
06:41Hidden in the dark.
06:45Planets like 51 Pegasi b.
06:55The first world outside our solar system,
06:58detected in orbit around a star similar to the Sun.
07:1451 Pegasi b. is a gaseous giant.
07:18It is half the mass of Jupiter.
07:23But it is closer to its star.
07:30Let's imagine what that planet would be like.
07:34A world in which titanic winds scratch the sky.
07:46And inside it, a rain of sapphires is cooking.
07:5751 Pegasi b. is a giant.
08:0251 Pegasi b. is a very strange world in every way.
08:10And we will soon discover that the galaxy is full of planets
08:14that are nothing like what we have seen in our solar system.
08:26Planets enveloped by intense radiation.
08:32Planets with maltreated surfaces
08:35and swept away by the stroboscopic light of high energy
08:38that irradiates their star.
08:46Or worlds so cold that their atmosphere has frozen.
09:0251 Pegasi b. is a giant.
09:14Or large, swollen planets.
09:21With the density of polystyrene foam.
09:26And unfathomable atmospheres.
09:35These discoveries prove that, in a way, we are not alone.
09:42There are other worlds waiting to be explored.
09:56We calculate that in the Milky Way there are more planets than stars.
10:02Hundreds of thousands of millions.
10:07That means hundreds of thousands of millions of places to seek life.
10:14But there is a complication.
10:16Not all those worlds are like this one.
10:19Not much less.
10:26The first planets we found seemed too strange, too large.
10:30And often they were too close to their stars
10:33for the survival of living beings.
10:45If we wanted to find worlds in which we could explore,
10:49we would have to go to the Milky Way.
10:52If we wanted to find worlds in which life could exist,
10:56we would have to look for smaller rocky planets
10:59and in orbits farther from their stars.
11:07We needed to look for another Earth.
11:10Four. Three. Two.
11:13Ignition. One. Zero.
11:16And takeoff of the Delta II rocket with the Kepler telescope
11:20in search of planets similar to ours.
11:25The tracking was transferred to space
11:27when NASA launched the Kepler space telescope.
11:33Separation completed.
11:36In search of planets similar to Earth
11:39in the vastness of the galaxy.
11:51Kepler traveled 150 million kilometers in space
11:59until it settled in a stable orbit around the Sun.
12:06Kepler's orbit around the Sun
12:14From there it had a fixed and clear view
12:22of a very precise area of the firmament
12:25in the constellation of the swan.
12:36And it exposed its extremely sensitive photometer
12:46to the light of 150,000 stars.
12:57And it began to look for distant worlds similar to Earth.
13:05Kepler's orbit around the Sun
13:24Kepler doesn't detect planets directly.
13:27They are far too small.
13:29They are too small,
13:32and they don't emit light of their own.
13:35They only glow very faintly
13:37reflecting the ambient light of their stars.
13:43So Kepler has to detect planets indirectly.
13:46Imagine that a moth just flew across the light of the lighthouse.
13:53Now, I wouldn't see the moth,
13:55but if I had such a very sensitive detector
13:58and everything was well aligned,
14:00I would see that the intensity of the light dims.
14:04And that's how Kepler detects planets.
14:07If an alien astronomer in a distant solar system
14:10looked at our Sun with the correct alignment,
14:13he would see the trace of the Earth
14:16crossing in front of our star.
14:19He would see that the light of the Sun dims by one hundredth.
14:23It's very little, but it's enough.
14:26And if they saw that dimming was regular,
14:29and it's all done once every year,
14:32then they would infer that there is a planet
14:35orbiting around the star.
14:57Kepler's photometer is extraordinarily sensitive.
15:04But it only sees a regular darkening of pixels.
15:12Even if it's very little data.
15:19Astronomers have begun to build an image of those worlds
15:23that dim the light of the stars.
15:34Worlds that could somehow look like the monster.
15:47Worlds like Kepler-36b.
15:54This planet was one of the first discoveries of the Kepler telescope.
16:08It orbits around a star similar to ours,
16:11so at first glance it's a world that would be familiar to us.
16:16Its mass is four times the mass of the Earth.
16:20And it was one of the first of a new kind of planet.
16:25A super-Earth.
16:46Kepler's data not only allows us to say
16:49that there is a planet around that star,
16:52it also allows us to capture some of its characteristics.
16:55So by looking at the size, weight, light, phase,
16:58and the rise and fall of the light,
17:01and the time at which it dims,
17:04we can measure the orbit of the planets.
17:07And if there are multiple planets in the system,
17:10we can even estimate their masses.
17:13So astronomers can get an idea of the worlds they discover.
17:30But the more detailed our information about the Kepler-36b planet was,
17:34the less this super-Earth looked like our planet.
17:43Kepler-36b
17:48It orbits very close to its star,
17:51going around every 14 days.
18:01And it has company.
18:07A gaseous giant,
18:11that keeps an orbit exceptionally close to its own.
18:17The proximity of its mother star and its brother planet
18:21allows us to imagine the strange conditions
18:24that could be found on the surface of Kepler-36b.
18:29Kepler-36b
18:39It is possible that the planet has a synchronous rotation,
18:43so that an hemisphere would always be oriented towards the star.
18:53The scorching heat of this hemisphere
18:56would melt the ground,
19:03creating lava rivers that would cross the surface.
19:18The planet could experience violent eruptions
19:21when the gravitational pull of the gaseous giant
19:24triggers an extreme volcanism,
19:34every time it passes by.
19:54Kepler-36b
20:02But Kepler-36b could also be an ice planet.
20:16Due to the synchronous rotation,
20:19the other side would be permanently behind the star.
20:25This leads us to imagine an ice hemisphere
20:28enveloped in an eternal darkness.
20:46For now, it's all speculation.
20:50But at least we have begun to create an image of these worlds.
20:54We imagine a world in which the sun
20:57is always placed at the same point in the sky.
21:00One side of the planet would be submerged in an eternal night,
21:04and the other would live an eternal day.
21:07In fact, the twilight strip between day and night
21:11would also suffer from extreme conditions.
21:20So, Kepler-36b demonstrates that the composition of a planet
21:24is not enough for it to be habitable.
21:27You have to take into account the details of its orbit,
21:31and the nature of the other objects in the solar system
21:35that it orbits around its star.
21:49Kepler-36b
21:58Kepler-36b is just one of the thousands of planets
22:02that the Kepler telescope has discovered.
22:11We know without a doubt that in our galaxy
22:14there is a very varied collection of extrasolar worlds.
22:19Kepler-36b
22:25Each one of the more than 4,000 planets discovered so far
22:29is different from all the others.
22:32They all seem strange and exotic to us.
22:35There is certainly no planet that is identical
22:38to the planets in our solar system.
22:41This shows us a deep truth about the universe.
22:45The laws of nature that have formed the planets
22:48are simple and identical everywhere.
22:51And the fundamental ingredients of which the planets are made
22:55are also simple and identical everywhere.
22:58But the nature of a planet also depends on the history of its formation
23:02and the environment that surrounds the mother star from which it was formed.
23:07And those are all totally and absolutely different.
23:12Each planet tells us a different story.
23:15In a way, they are similar to human beings.
23:18And this wholly unexpected and exciting discovery
23:22certainly complicates the search for life.
23:32We need to limit the search for planets
23:37that are not too far from their mother stars.
23:47Planets at the right distance from their surfaces
23:50so that they are habitable.
23:57Distant worlds with a precious ingredient
24:00that makes the Earth a living planet.
24:06Planetary Science
24:23It would be logical to ask ourselves
24:26if we can apply all our knowledge of life on Earth
24:29to planets elsewhere in the universe.
24:32Well, I would say, yes, we can.
24:35Because the laws of nature are universal.
24:38The laws of physics and chemistry that sustain the biology of the Earth
24:42will affect every planet out there in the universe,
24:46whether we discover it or not.
24:56The chemistry of life is based on a few basic ingredients,
24:59carbon, nitrogen, oxygen, and iron.
25:04And it also requires a fast energy supply of good quality,
25:08coming from the heat of the interior of the planets
25:11or the light of the stars.
25:17But life on Earth depends on an extra ingredient,
25:20which is very important, liquid water.
25:23Liquid water is a deceitfully complicated substance.
25:28It's a great solvent, but inside it has structures
25:31that form and disappear constantly,
25:34structures that act as a kind of snap,
25:37around which biology develops.
25:44Organic molecules are aligned in that snap
25:47so that they can react together.
25:51Now, on Earth, all living beings need liquid water to survive,
25:55and I would say this is a very good assumption,
25:58that every living being anywhere in the universe
26:01will require it as well.
26:26In the universe, there is a lot of water.
26:31In our galaxy, large deposits have been discovered,
26:34among the gas clouds of the giant nebulae.
26:41But the abundance of water does not necessarily mean
26:44that it accumulates on planetary surfaces,
26:47forming oceans.
26:51Of the eight planets in our solar system,
26:54there is only one in which liquid water
26:57flows permanently on its surface.
27:04A marine world in which life began a long time ago.
27:11And there is no doubt that there is a lot of water
27:14on the surface of our planet.
27:20But how long?
27:40Around 4 billion years ago,
27:43life on Earth began in places very similar to this,
27:46where there is geothermal activity,
27:49a source of energy in contact with rich concentrations
27:52of reactive minerals and chemical elements.
27:56But also, and this is the fundamental,
27:59there was a magical solvent, liquid water.
28:03Now, many planets in the galaxy
28:06probably have this,
28:09but very few people think
28:12that large masses of liquid water
28:15are on the surface.
28:18So, in the astrobiological community,
28:21the phrase is repeated,
28:24if you want to find life, look for water.
28:41As life evolved on Earth,
28:49at 124 light-years,
28:52in the collapse of a cloud of gas, dust and ice,
29:02a small star was born.
29:11The remains of the cloud's whirlpool condensed
29:14and formed a new world.
29:19In 2015, the Kepler telescope
29:22found a planet orbiting relaxedly
29:25in the habitable zone of its star.
29:42Its mass multiplies by the number of stars
29:46Its mass multiplies by 8 the mass of the Earth.
29:50K2-18b is a giant.
30:02And it has a huge gravitational attraction.
30:15If the planet is rocky,
30:18that attraction would have allowed it
30:21to preserve a tense atmosphere.
30:24K2-18b has all the attributes
30:27of an aquatic world.
30:34And a legendary space telescope
30:37had in sight the new discovery of Kepler.
30:46The most powerful of the space telescopes
30:49joined the search.
30:57Hubble inspected the light of the mother star
31:00when K2-18b passed in front of it
31:06and detected what could be a weak indicator
31:10of water vapor.
31:18It is possible that we have finally found proof
31:21of the existence of water in an extrasolar world
31:24124 light years from Earth.
31:30This was the first observation of water vapor
31:33in the atmosphere of a planet
31:36orbiting the habitable zone around its star.
31:39The measurement obtained of the amount of water vapor
31:42is very imprecise.
31:45It oscillates between 0.01 and 50%.
31:48It is very far away.
31:51The important thing is to compare it with Earth
31:54which only has a small percentage of water vapor
31:57in the atmosphere.
32:00The discovery is important for two reasons.
32:03First, to measure the atmosphere and water vapor.
32:06Secondly, if the measurement is lower than 0.01%
32:09and the percentage is low,
32:12then that is consistent with the possibility
32:15that this planet has oceans on its surface.
32:25At this moment there is an intense scientific debate
32:28about the nature of this planet.
32:32Could it be a small Neptune?
32:35A gaseous planet?
32:42But we can also dream of a rocky extrasolar world
32:45with skies full of clouds
32:52where drops of water accumulate
32:55and precipitate.
33:02Feeding huge oceans
33:07that cover the surface of a giant planet.
33:14An aquatic world.
33:25A world where there is a lot of sand.
33:31A mixture of life.
33:39K2-18b is exciting.
33:42It is the smallest world with atmosphere
33:45that we have analyzed.
33:48And we found that its mass, its density and its orbit
33:51are consistent with the possibility
33:54that it is a world with water.
33:57And it might be a world
34:00with oceans on its surface.
34:03We don't know for sure.
34:06But just imagine how that small, far away world
34:09could orbit around a faint red star.
34:18The Kepler telescope
34:21continued to make many more discoveries.
34:31Until in October 2018
34:34it ran out of fuel.
34:44In its nine years of activity
34:47it found more than 2,500 extrasolar worlds.
34:51And it showed us that planets
34:54potentially similar to Earth
34:57could be very common.
35:14We estimate that in our galaxy
35:17there could be about 20 billion worlds
35:20potentially similar to Earth.
35:23That is, rocky planets
35:26in the habitable area around the star
35:29are possibilities of housing liquid water on the surface.
35:3220 billion potential homes for life.
35:47What we can't calculate
35:50is the probability that life could begin
35:53when the conditions are right on a planet.
35:56We only know the experience of our world.
35:59We know that life on Earth
36:02began as soon as it was possible.
36:05The oceans on the surface emerged
36:08when the Earth ended up deforming and cooled off.
36:11So that might suggest that although the origin of life
36:14is reasonably probable.
36:17So I think that there is at least a possibility
36:20that life has begun in some
36:23or in many of the 20 billion worlds in our galaxy
36:26similar to Earth.
36:31But I think there are two questions about life.
36:34One question is the origin and existence of microbes.
36:37But often when we talk about extraterrestrials
36:40we don't think about microbes
36:43but about complex and intelligent creatures
36:46with which we could speak.
36:49We think about civilizations.
36:52What is the probability that there are other civilizations on the Milky Way?
36:55Well, we don't know the answer.
36:58But there are observations
37:01that we also see in the Milky Way
37:04that might lead us to make certain conjectures.
37:14NASA Jet Propulsion Laboratory
37:17California Institute of Technology
37:44We don't know exactly
37:47how we have become such complex and intelligent creatures.
38:01But we do know for a fact
38:04that life on Earth has not been at this level since the beginning.
38:09We are the product of a history
38:12that has developed for more than a quarter of the age of the universe.
38:20From microbes
38:23to a global technological civilization
38:26that wants to contact other civilizations.
38:30At the moment we are still surrounded by silence.
38:33The messages we have sent to the cosmos
38:36remain unanswered.
38:39The telescopes we use to scan the space
38:42in search of extraterrestrial signals
38:45remain undetected.
38:48That does not mean that there are no other civilizations.
38:51Perhaps we have been looking for what we should not have
38:54in the wrong place.
38:57But I think the answer to the question of the great silence
39:00is here, on Earth.
39:03It took 4 billion years of stability
39:06and when we look at the other worlds of the Milky Way
39:09we find that stability and time
39:12are very rare commodities.
39:27In 2013, the European Space Agency
39:30launched the Gaia Space Telescope.
39:36Its mission is to probe the stars of our galaxy,
39:39the Milky Way.
39:43It has mapped thousands of millions of stars.
39:50Each star could be the center
39:53on which alien worlds orbit.
39:59And several patterns have already emerged.
40:06Not all stars are alone.
40:17Some have company.
40:36And as strange as it may seem,
40:39the Gaia mission has discovered
40:42about a million binary or multiple stellar systems.
40:48We already knew about the existence
40:51of binary and multiple stellar systems.
40:54But we did not know exactly
40:57whether they were common or not.
41:00But now we have a huge amount of high-precision data,
41:03including the data of the Gaia mission,
41:06which tells us that about 50% of the stars similar to the Sun
41:09are in multiple stellar systems.
41:12And for the most massive stars,
41:15the percentage reaches 80%.
41:21And the prevalence of multiple stellar systems in the galaxy,
41:24how does it affect the possibilities
41:27of finding another Earth?
41:31Could there be planets like Earth
41:34in multiple stellar systems?
41:37And in that case, what could be its future?
41:45In 2020, we found a clue.
41:50We discovered a planet the size of Mars,
41:53moving freely through the galaxy.
41:56Let's call it a rebel planet.
42:01Now, if the planets do not form by themselves
42:04in interstellar space,
42:07where does this planet come from?
42:24The dawn.
42:31Illuminated not by one star,
42:39but by two.
42:50Perhaps the rebel planet
42:53was born in a nearby binary system.
43:00It was formed by two stars.
43:10Subject to the gravitational force of two stars.
43:21Perhaps its orbit was unstable.
43:31And the two stars fought to control their destiny.
43:49In the systems of a single star,
43:52the weak gravitational interactions between planets
43:55can also alter their orbits.
43:58And in a double stellar system,
44:01they are not only subjected to the gravitational force of others,
44:04but also to the attraction,
44:07even stronger than that of another star.
44:10Although a planet enters a stable orbit,
44:13it is very likely that it will not remain in it for a long time.
44:16But when it comes to a double stellar system,
44:19there is a very thin line between order and chaos.
44:23Up to the smallest changes in the orbit of a planet
44:26can cause drastic changes in the climate.
44:29That is why it is unlikely
44:32that the conditions of the surface of a planet
44:35in a double system will remain stable for long enough
44:38for intelligent life to evolve.
44:53And sometimes the changes in the orbit of a planet
44:56may not be precisely subtle.
44:59It is possible that some approach
45:02would give the rebel world
45:05the definitive gravitational kick.
45:29Throwing it outside the system
45:32and freeing it from the clutches of its stars.
45:35It is possible that some approach
45:38would give the rebel world
45:41the definitive gravitational kick.
46:00To wander on its own.
46:08On a journey through the galaxy.
46:30Far from the heat of its stars.
46:34Any trace of liquid water it had
46:42would have frozen.
46:49The atmosphere that protected it.
47:00It would freeze on the surface.
47:08The rebel planet would become like this.
47:13In a world without the right conditions for life.
47:21A lonely and drifting planet.
47:30To be detected by us.
47:34Millions of years later.
47:38A little wandering planet
47:41similar to Earth.
47:44That will wander through the darkness of space
47:47for all eternity.
47:59This lonely wandering planet
48:02is not a unique case.
48:05Although they are very difficult to detect,
48:08it is estimated that there are more than 100 billion of them in our galaxy.
48:11It is possible that the rebel planets
48:14are the most common type of planet in the Milky Way.
48:17And although we think that most were expelled from their system
48:20shortly after their formation,
48:23it is an indicator that stellar systems
48:26and complex life have possibilities to evolve
48:29for billions of years.
48:43The search for another planet with life has just begun.
48:51But we have already learned a lot.
48:57We have found our first rocky worlds.
49:01Some in a habitable area around certain stars.
49:15Some with the possibility of having water in a liquid state on its surface.
49:20Candidate worlds for our next adventure.
49:26And future missions in search of life evidence.
49:35We have also found a huge number of strange and mistreated worlds
49:41orbiting around violent stars.
49:52And many rebel planets.
49:57Planets where it seems impossible to exist what we understand
50:00by complex life.
50:10Maybe we will find in those worlds
50:13the explanation why our planet,
50:16for the moment, is still an exception.
50:27Our planet has been largely free from violence,
50:30chaos and the constant change
50:33so common in the Milky Way.
50:36It has witnessed some kind of massive extinction.
50:39But the chain of life has not been interrupted
50:42at any time since the beginning of the Milky Way.
50:45It is a chain of life that has not been interrupted
50:48since the beginning of the Milky Way.
50:51It is a chain of life that has not been interrupted
50:54at any time since 4 billion years ago.
50:57If that is what is needed for life to begin and evolve
51:00until it becomes a civilization,
51:03there could be thousands of millions of worlds with life,
51:06but without civilizations.
51:09It is still a hypothesis with a foundation.
51:12An opinion, in a way.
51:15Although given the depth of the questioner,
51:18the solidity of that foundation does not matter much.
51:21It would be absurd if we stopped looking
51:24inside and outside of our galaxy.
51:31Because it is possible that we have first glimpsed
51:34a world beyond the Milky Way.
51:46About 30 million light years away,
51:50in the spiral arms of the galaxy Remolino,
51:58there is a planet the size of Saturn.
52:09This discovery represents a progression of our horizon.
52:13The beginning of the search for extragalactic planets.
52:26I never thought that I would see the discovery
52:29of a planet orbiting around a star in another galaxy.
52:33This opens up the exciting possibility of exploring
52:36not only if we are alone in our galaxy,
52:40but if we are alone in the universe.
52:47The answer to that question is so far in the future
52:50that it is possible that we might never find it.
52:54But by saying that the question of whether we are alone is deep,
52:58I mean that answering it would teach us much more
53:01about what it means to be human.
53:05Well, I think with every world we explore,
53:08we become a little more human
53:11because of our ability to lay down the foundations
53:14to ask ourselves questions
53:17to which we may never have answered in our lifetime.
53:20Asking questions for our children or our grandchildren
53:23is a fundamental part of what it means to be human.
53:26It is a fundamental part of what makes us human.
53:29It is a fundamental part of what it means to be human.
53:32It is a fundamental part of what makes us so special
53:35in this little world,
53:38looking at the stars,
53:41whether we are alone or not.
53:59Five, four, three, two, engine start.
54:04One, zero.
54:06Liftoff of the Delta II rocket with the Kepler telescope
54:09in search of planets similar to ours.
54:14The joint work of thousands of people
54:17has become a reality.
54:20Separation complete, Adam.
54:23It was so emotional to see the project
54:26in which they had worked for so many years, decades,
54:29finally go to space,
54:32and all that hope and promise, hope and promise,
54:35traveling between machinery.
54:42The Kepler telescope was an immediate success.
54:45It discovered more than 2,000 new planets
54:48in its first four years of operation.
54:52But in the summer of 2012,
54:55the team faced a challenge that threatened the entire mission.
55:03One of the fundamental elements of the Kepler
55:06is the reaction wheels that rotate
55:09and keep it focused on the targets,
55:12always pointing to the same stars without moving,
55:15and the telescope has four of those wheels.
55:21And we knew that the gyroscopes of the spacecraft
55:24end up failing, but we only had a couple of them to spare.
55:32And after all that,
55:34three months later, the second failed,
55:37and since we needed three,
55:40we were no longer able to keep the Kepler field of view.
55:44I had hope that they would find a way
55:47to work with two gyroscopes, and they did.
55:52So very clever people, engineers, scientists,
55:55said, we're going to use solar radiation
55:58as if it were the third wheel.
56:01We'll make it reflect sunlight,
56:04and with the other two wheels working,
56:07we'll be able to point to space.
56:14That's some good news, actually.
56:17The fact that Kepler was going to go off,
56:20we could get all kinds of other stars,
56:23and that was a big boost for stellar astronomy.
56:30After four more years of discovery,
56:33they found more than 2,600 planets.
56:37It became our main planet hunter,
56:40until the moment...
56:45The sending of the order of Apagado was a very sad moment.
56:48Now it's asleep.
56:51It's in orbit around the sun, and it will remain in orbit.
56:54But since it was launched from Earth,
56:57the orbit will bring it back to us again.
57:00It will visit us in about 40 years,
57:03and I hope that people will say,
57:06it's a historic telescope.
57:09It taught us a lot about those planets.
57:12They will go up to pick it up and bring it back
57:15to us again in a little while.
57:18.
57:24.
57:27.
57:30.
57:33.
57:36.
57:39.
57:42.
57:48.