Ces faits sur l'espace vous rappelleront à quel point nous sommes petits

Sympa

Animation créée par Sympa. ---------------------------------------------------------------------------------------- Musique par Epidemic Sound https://www.epidemicsound.com   Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna​ ---------------------------------------------------------------------------------------- Nos réseaux sociaux : Facebook: https://www.facebook.com/sympasympacom/ Instagram: https://www.instagram.com/sympa.officiel/  Stock de fichiers (photos, vidéos et autres): https://www.depositphotos.com https://www.shutterstock.com https://www.eastnews.ru ----------------------------------------------------------------------------------------  Si tu en veux encore plus, fais un tour ici:  http://sympa-sympa.com

Transcript

00:00:00 The sun is about to turn around because its magnetic poles are inverting.

00:00:04 Just like the Earth, the sun has a magnetic north and a magnetic south.

00:00:08 However, unlike our planet, the process of inversion of the poles of the sun is more frequent and easier to predict.

00:00:15 The next reversal is scheduled for this year between April and August.

00:00:19 As apocalyptic as it may seem, you don't have to worry.

00:00:23 If you are about 30 years old, you have already experienced this phenomenon more than once because the sun is inverted every 11 years.

00:00:31 You probably didn't notice any changes at the time because this process has no major impact on terrestrial life.

00:00:37 But this time, things could be a little different.

00:00:42 On Earth, sea currents are movements that play a crucial role in influencing the climate and the weather and distributing the heat of the equator to the poles.

00:00:51 On the sun, these currents are more like a plasma ocean.

00:00:55 But they do not only transport heat, they also transport electromagnetic energy.

00:01:00 This happens because the sun is a huge ball of incandescent and ionized gas that continues to circulate inside its nucleus.

00:01:09 By fusing these hydrogen atoms to form helium, our star releases a huge amount of energy, producing these powerful electric currents.

00:01:18 And every time you have such currents, you have magnetic fields.

00:01:22 It's easier to visualize if you think back to this classic experiment with a copper wire and a nail that you probably made at school.

00:01:30 When an electric current passes through a wire, it creates a magnetic field around it.

00:01:35 So when you connect a wire to a battery and wrap it around a nail, this nail becomes magnetized.

00:01:41 It's similar to the way electric currents generate magnetic fields around the sun.

00:01:48 The whole process that generates the magnetic field of the sun is what we call a dynamo.

00:01:56 We can't see it directly, but we can see the effects on the surface of the sun.

00:02:01 When plasma and magnetic flows become unstable, they manifest in the form of solar torches.

00:02:07 You know, those dark areas on the surface of the sun.

00:02:10 We still don't know much about how this dynamo works, but scientists have understood something important after observing these solar torches over the centuries.

00:02:20 This process follows a certain pattern.

00:02:22 Every decade or so, it reorganizes itself.

00:02:26 The magnetic fields of the poles of the sun diminish until they completely disappear, then they return, but with an opposite polarity.

00:02:34 In the 1950s, researchers discovered that when the solar torches began to intensify, it meant that the poles were preparing for an inversion.

00:02:43 And in recent years, solar activity has been completely out of the ordinary.

00:02:47 More solar eruptions, electromagnetic radiation bursts, and more plasma ejections into space.

00:02:54 It's as if we were sitting in the first row of the largest pyrotechnic show in the solar system.

00:02:59 In fact, the sun has probably not been so lively over the last two decades.

00:03:04 At present, experts believe that the magnetic fields of the poles are almost synchronous and are weakening little by little, getting closer and closer to zero.

00:03:14 But we have not yet reached the point of inversion.

00:03:17 Although it may seem that the sun reverses its poles every 11 years, like a clock, the truth is that it is not so clearly defined.

00:03:26 This path is not without obstacles, and some aspects of the phenomenon are still very difficult to predict.

00:03:32 Take the last solar cycle, for example.

00:03:35 The northern hemisphere began its magnetic inversion as early as June 2012, but then encountered an obstacle and stagnated around the neutral point until the end of 2014.

00:03:44 During this time, in the southern hemisphere, things are much more fluid, and the change in polarity occurred in 2013.

00:03:52 This time, solar activity seems more regular.

00:03:55 Things seem to unfold more smoothly during this cycle, with a more uniform transition of poles.

00:04:00 But here's the thing, this inversion process never repeats itself, and that's what makes this phenomenon so interesting to observe.

00:04:08 But at the same time, it is difficult to predict how this will affect us down here.

00:04:14 Here on Earth, we have no war to worry about these intense solar explosions, which occur at 150 million kilometers away.

00:04:22 But if, and we say "if", a solar storm were to hit our planet, the main threat it would pose would probably be the disruption of space communication satellites.

00:04:33 Nevertheless, things could take a different turn during the cycle of inversion planned for 2024, because the number of satellites in orbit has exploded in recent years.

00:04:42 The Starlink system, for example, involves more than 4,000 of them.

00:04:47 All these communication satellites and other GPS could be impacted, or even destroyed, by a powerful solar storm.

00:04:55 Although the chances of a powerful solar storm hitting Earth are slim, it is not impossible.

00:05:03 In 1859, during the Carrington event, a storm occurred near a peak of solar activity, causing overvoltages in the telegraphic lines, triggering fires and disrupting exchanges worldwide.

00:05:15 The Earth was silent when all these telegraphic communications were cut off.

00:05:20 Just imagine what a solar storm could do to our vast fleet of satellites today.

00:05:26 It could affect everything we depend on daily, from geolocation and space-based telecommunications to weather forecast services.

00:05:35 Electricity distribution on the ground could also be affected.

00:05:39 You can make a cross on YouTube, and even a nice one.

00:05:42 Because if such an event occurred today, it could put the Internet to bad use, cutting off countless people from the world.

00:05:49 Predictions say that if such an event occurred today, it would result in damage worth 600 to 2,600 billion dollars.

00:05:59 And we're talking about the United States alone.

00:06:02 Fortunately for us, solar storms as intense as the Carrington event only happen once every 500 years or so.

00:06:09 Bad news for communication satellites, but excellent news for the observers of Boreal Aurora.

00:06:17 During the Carrington event, dazzling auroras illuminated the sky and the spectacle of the polar lights spread far beyond the usual boundaries.

00:06:26 These Boreal auroras were seen to the south of Cuba and Honolulu, while australian auroras were seen to Santiago, Chile.

00:06:35 For many people around the world, this was their first sighting of such auroras, leaving them stunned in front of these unusually bright skies.

00:06:42 Some then thought it was the end of the world, while others woke up unusually early, believing that the sun had risen after hearing the birds chirping and all that light.

00:06:53 Today, we know that there is nothing strange about this, given that the appearance of auroras at such latitudes is one of the expected effects of the inversion of the magnetic poles of the sun.

00:07:02 Typically, these iridescent phenomena are observed between 60 and 75 degrees of latitude, but during the last inversion of the magnetic poles, in 2013, intense auroras were observed below 50 degrees.

00:07:17 Witnesses described these auroras as being "red blood" shooting on the skull and shining so brightly that you could read a newspaper in their own light.

00:07:28 It is important to study this phenomenon, rather than fear it. The inversion of the magnetic poles of the sun is actually a perfect opportunity for scientists to better understand how our star works.

00:07:39 And as there are still many pieces missing from the puzzle of solar dynamo, we are still unable to understand why some cycles are more intense than others, or to predict when an ejection of coronal mass will occur exactly.

00:07:53 But being able to predict them becomes more and more crucial as we venture into space.

00:07:59 The more people are in orbit around the Earth, the more exposed they are to these strong solar storms.

00:08:04 This is why the scientific community seeks to learn more precisely when such a storm could cause damage to our ships and our space stations.

00:08:13 In addition, this would help meteorologists to make better predictions, not only on Earth, but also in space.

00:08:21 The main goal would be to make space travel safer as our interest in lunar and Mars missions continues to grow.

00:08:29 Another reason why it would be important to learn more about the inversion of the poles of the sun, and to better understand how the mysterious heart of our star works.

00:08:39 This could indeed help us better grasp the aspect of other stars in the universe, and perhaps bring us closer to the answer to the ultimate question.

00:08:47 What are we doing here?

00:08:50 In 2017, a strange object was spotted in our solar system.

00:08:54 It had an oblong shape, a bit like a pancake.

00:08:58 None of the asteroids or comets we have ever observed look like this.

00:09:03 Its surface was also singular.

00:09:05 It was at least ten times more reflective than the average of objects drifting in space.

00:09:10 Some have claimed that it had an envelope comparable to polymethyl.

00:09:15 When it passed near the sun and moved away from our orbit, it accelerated beyond what our gravity would be able to explain.

00:09:23 At first glance, we would have said that this thing had a rocket attached to its back.

00:09:28 This unusual visitor even received its own name, "Oumuamua".

00:09:33 It comes from the Hawaiian language and translates as "lighter" or "visitor of a distant land".

00:09:38 And because of these characteristics, scientists soon wondered if it was really a visitor from an alien people.

00:09:45 Before getting into deep science fiction, astronomers first gathered the information they were "sure" about.

00:09:56 Starting with the fact that Oumuamua must have come from another solar system.

00:10:00 An unexpected event in its original system probably led to its ejection.

00:10:06 What we did not know was whether it was a comet or an asteroid.

00:10:11 Both are celestial objects orbiting around a sun.

00:10:16 But they have compositions that they complement radically and distinctly.

00:10:20 Comets are mainly composed of ice, dust and rocks, and are sometimes called "dirty snowballs".

00:10:27 When a comet approaches the sun, the heat causes the vaporization of the ice, releasing gas and dust particles into space.

00:10:36 This creates a luminous and sparkling tail that can extend for millions of kilometers.

00:10:41 Comets generally have an elliptical orbit, often taking them to the farthest edges of the solar system, closest to the sun.

00:10:53 Asteroids, for their part, are mainly composed of rocks and metals.

00:10:57 In our immediate neighborhood, they are the remains of the formation of the solar system

00:11:02 and are generally found in the asteroid belt that extends between Mars and Jupiter.

00:11:07 Unlike comets, asteroids do not have the same path as those approaching the sun, because they do not have ice.

00:11:15 Their orbits generally follow a more circular trajectory than comets.

00:11:21 In all likelihood, Oumuamua should be a comet, because it seems to come from a different place in the universe.

00:11:28 However, it does not present the typical signs of a cometary activity.

00:11:32 Wait a minute, does the cometary have a cometary style?

00:11:36 It's up to you to see. Oumuamua does not have a tail and does not spit out gas during its passage, unlike me.

00:11:43 Although it behaves more like a comet, it looks more like an asteroid.

00:11:49 Another big question is, how did scientists manage to spot Oumuamua in the first place?

00:11:57 Given the immensity of space-time, it is quite remarkable.

00:12:01 Stars have life spans extending over millions, if not billions of years.

00:12:06 And the formation of a solar system takes several hundred million years.

00:12:10 Even the fastest objects take tens of millennia to travel from one star to another.

00:12:16 On the other hand, humans have only observed the sky with their telescopes for about 400 years,

00:12:22 a tiny fraction of space-time.

00:12:24 And it is only in recent decades, if not recent years, that we have obtained the technology

00:12:30 allowing us to detect and track fast and dim objects.

00:12:34 Either such rocks are very common, or we were very lucky with our instruments,

00:12:39 or Oumuamua just wanted to be seen.

00:12:45 Another question concerns the origin region of such objects.

00:12:48 It is very unlikely that Oumuamua comes from a mature and stable solar system.

00:12:53 It is because such systems do not eject enough matter to spread across the galaxy.

00:12:58 A rock can sometimes be projected, but it can rarely go that far.

00:13:03 Younger systems, however, act differently.

00:13:07 In these chaotic environments, collisions, fusions and other migrations occur all the time.

00:13:14 Many small rocks are so, and are the perfect candidates for ejection.

00:13:19 The solar system that ejected Oumuamua must have had a planet similar to Jupiter.

00:13:24 Its massive size and gravity could influence other objects through the system,

00:13:29 potentially causing ejections.

00:13:32 But all solar systems do not develop planets of Jupiter's size.

00:13:36 Often, these massive planets end up getting closer to their stars,

00:13:41 becoming warmer versions of the gas giant.

00:13:45 Such planets, in orbit close to a sun, are less likely to eject matter from afar.

00:13:52 Planets similar to Neptune could also have played a role.

00:13:56 Although they are not as massive as Jupiter,

00:13:59 they tend to nest near the periphery of solar systems.

00:14:04 Our own system thus has the Kuiper Belt,

00:14:08 a real comet reservoir, in its periphery.

00:14:11 During the first stages of the formation of a solar system,

00:14:15 interactions between planets similar to Neptune and such debris are frequent.

00:14:20 However, the discovery of such planets tends to alter the system's ability to verify.

00:14:25 Our methods of detecting such exoplanets work better with massive objects,

00:14:29 closer to their stars, which complicates the detection of their further homologues.

00:14:37 Humamua has also found himself associated with a certain theory

00:14:41 about how life would have appeared in the universe.

00:14:44 Permian thought.

00:14:46 It is a hypothesis that suggests that life exists everywhere in the universe

00:14:50 and can be distributed between planets by various means,

00:14:54 such as asteroids, comets and even special vessels.

00:14:58 It claims that life must have originated from a given region of the universe,

00:15:03 after which it spread to other celestial bodies.

00:15:08 Adepts of this theory suggest that such interstellar objects

00:15:12 could potentially be transported by tiny microbes,

00:15:15 these fundamental components of life, between stellar systems.

00:15:19 If such objects were to hit a planet or a moon,

00:15:23 their perian transverse organisms would be a cell, a celestial body.

00:15:28 For the moment, there is no evidence to support the idea

00:15:33 that such objects in particular transported life between the solar systems.

00:15:37 After years of research, the general consensus is that Humamua was indeed a comet.

00:15:45 The reason why it moves in such a strange way

00:15:48 is that it could present hydrogen frozen at its surface,

00:15:51 which reacts to the contact of sunlight.

00:15:54 The closer it got to our star, the faster it released this hydrogen,

00:15:58 changing its trajectory through our solar system.

00:16:02 Its color also supports this theory.

00:16:05 It is red, which could mean that it was hit by cosmic rays for a long time.

00:16:11 The more it was bombed by these rays,

00:16:13 the more hydrogen it accumulated during the process.

00:16:17 But as they can't be sure, astronomers plan to follow this visitor.

00:16:22 The idea is to send a mission to examine it.

00:16:25 It is already far from us, but it may not be too late.

00:16:29 We could be able to send a fairly fast probe to catch the comet.

00:16:34 This plan was named "Projet Lyra"

00:16:37 and aims to exploit the orbit of Earth and Jupiter

00:16:40 in order to send a probe far enough to reach Humamua.

00:16:44 If it works, it will be the fastest spacecraft we have ever sent into the universe.

00:16:49 The trajectory of the space probe would involve using the attraction of our planet

00:16:54 and that of Jupiter as a gravitational front effect.

00:16:58 The probe would first leave our planet,

00:17:00 then return to Earth's orbit before going to meet the attraction of Jupiter.

00:17:05 It would be sent back to our planet a second time,

00:17:09 or it would be ejected with enough force to reach the comet.

00:17:16 The "Projet Lyra" also aims to follow a second distant visitor,

00:17:20 named Borisov.

00:17:22 This comet was discovered by an amateur astronomer and now bears his name.

00:17:27 What is fascinating about it is that, well, it is truly impeccable.

00:17:32 Just like our experience with Humamua,

00:17:35 we have never observed anything similar to Borisov either.

00:17:38 Studies of light from its dust and gas envelope

00:17:42 show that it is quite clean compared to other space objects.

00:17:46 After being spotted for the first time in August 2019,

00:17:50 astronomers studied its trajectory through our solar system

00:17:54 and concluded that it also came from another star.

00:17:57 But Borisov gave us more time to study it,

00:18:00 because we spotted it earlier in its journey through our neighborhood.

00:18:04 Researchers used advanced telescopes to examine the dust emanating from Borisov.

00:18:09 They discovered that it emitted more than 180 kg of dust every second.

00:18:14 We also found that Borisov contained more carbon monoxide

00:18:18 than the comets of our solar system in general.

00:18:21 However, this quantity is not the same everywhere on the comet.

00:18:26 This tells us that the space object probably started to form near its star of origin,

00:18:32 before moving away.

00:18:34 Maybe because of larger planets in its immediate neighborhood.

00:18:37 Borisov's light is much more polarized than the light coming from other comets we have observed,

00:18:43 and its cloud is perfectly homogeneous.

00:18:46 This suggests that Borisov has never interacted with another star.

00:18:50 We could get closer to the discovery of a huge and icy planet beyond Neptune's orbit,

00:18:56 and sorry, Pluto, it's still not you.

00:19:00 Recently, a map of the universe using data from a Hawaiian telescope

00:19:04 eliminated about 78% of the possible emplacements of this mysterious "Who ate Charlie?" from space.

00:19:12 Some call it "Planet 9", while others prefer "Planet X".

00:19:17 Anyway, it has been controversial since its existence was suggested for the first time.

00:19:23 And it is mainly due to the fact that no study so far has been able to answer the big question.

00:19:28 Does it really exist?

00:19:30 If it were to be discovered, Planet 9 would be classified as the 5th largest planet in our solar system,

00:19:36 with a mass 10 times greater than that of the Earth.

00:19:39 It is also thought that it would be gaseous, just like Uranus.

00:19:43 An initial study of Planet 9, dating from 2016, suggests that this new colossal planet

00:19:49 would have an orbit 20 times further from the Sun than Neptune, which is located at about 4.5 billion kilometers.

00:19:57 As a result, Planet 9 would take between 10,000 and 20,000 years to complete a single orbit around the Sun.

00:20:04 If its existence were proven, this still unknown world would dominate a region

00:20:08 larger than any other known planet in our cosmic neighborhood.

00:20:14 All these hypotheses are very intriguing, but without any evidence or observations allowing to support them.

00:20:20 Before rejecting them as simple crazy assumptions,

00:20:23 it is important to note that researchers have relied on complex mathematical models

00:20:28 and computer simulations to speculate on the characteristics of this planet.

00:20:33 Because that's what scientists do.

00:20:35 The existence of this hypothetical planet would explain various mysterious interactions observed beyond Neptune.

00:20:41 We are specifically talking about the Creeper Belt,

00:20:44 a huge ring-shaped region filled with ice debris dating from the formation of the solar system,

00:20:50 including comets and dwarf planets like Pluto.

00:20:53 What happens is that the six furthest objects in the Creeper Belt have elliptical orbits,

00:21:00 which are all oriented in a similar direction to the physical space

00:21:04 and tilted about 30 degrees down compared to the orbital plane of our eight known planets.

00:21:10 What is not a mystery is that despite the distinct orbital speeds around the Sun,

00:21:16 it is still possible that such a coincidence occurs by chance is extremely low,

00:21:23 about 0.007%.

00:21:26 Thus comes the theory of the new planet,

00:21:29 a massive hypothetical celestial body that offers a plausible explanation for this strange phenomenon,

00:21:34 by potentially exercising a gravitational attraction that shapes its orbits.

00:21:41 The initial theory did not go far in the face of accusations of observation bias and miscalculation.

00:21:47 Then, in 2017, another study emerged,

00:21:50 reviving the idea that maybe, after all, the new planet would be right there somewhere.

00:21:55 This time, Spanish astronomers have tried an innovative approach.

00:21:59 By focusing on the observation of extreme trans-Neptunian objects,

00:22:03 these celestial bodies orbit around the Sun in very stretched elliptical trajectories,

00:22:07 with average distances exceeding 22 billion kilometers.

00:22:11 Their research suggests that the distance between the orbital nodes of these objects and the Sun

00:22:16 could provide us with clues about the location of the new planet.

00:22:20 Do you see, these nodes are the points where the orbit of a celestial body intersects the plane of the solar system.

00:22:26 When these objects reach such a point,

00:22:28 they are more likely to interact with other celestial bodies of the system,

00:22:32 which can cause significant changes in their orbits, or even collisions.

00:22:38 So, if the trajectory of these extreme trans-Neptunian objects remains stable, everything is fine.

00:22:43 But if this is not the case, well, it is a sign that something else, something big, disturbs their orbit.

00:22:50 And that's exactly what this study has discovered.

00:22:52 There is something invisible there, which diverts these objects from their path.

00:22:57 And this something could be a planet 300 to 400 times further from the Sun than the Earth.

00:23:03 To this day, the study of extreme trans-Neptunian objects

00:23:06 is the most tangible proof that we have of the existence of the new planet.

00:23:11 And if you are still not convinced by this theory,

00:23:14 know that strange movements like this have already led to the discovery of planets in the past.

00:23:20 Neptune, for example, was spotted because the movement of Uranus

00:23:24 did not quite correspond to the predictions of Newtonian gravity.

00:23:27 But this deviation from its orbit could be explained

00:23:30 if it was caused by the attraction of an unknown planet.

00:23:34 And that's how we discovered Neptune.

00:23:37 Let's move on to 2021.

00:23:41 And the debate persists around the mysterious new planet.

00:23:44 After having revised some old assumptions,

00:23:47 studies are now leaning towards the idea that this planet would accomplish a revolution around the Sun every 7,000 years.

00:23:53 This is a big news.

00:23:55 Because this means that this planet could be closer than we thought,

00:23:59 which would facilitate its detection by our telescopes.

00:24:02 The study also suggests that there is a 99% chance

00:24:06 that the orbits shifted from these distant objects are all due to this invisible planet,

00:24:11 and not to a simple cosmic coincidence.

00:24:13 At present, the chances that this whole anomaly is only random

00:24:18 are reduced to 1 in 250.

00:24:21 Which is much better than a chance of 10,000, as in 2016.

00:24:25 All these optimistic figures have led us to where we are today.

00:24:32 To keep hope and develop better equipment to pursue the search for the new planet.

00:24:37 As mentioned earlier, researchers in Hawaii have created a kind of "treasure map"

00:24:43 by using the panoramic reference telescope

00:24:46 and its rapid response system to eliminate 78% of its possible locations.

00:24:52 This is very good news, given the difficulty of finding a planetary needle in a cosmic haystack.

00:24:59 But unfortunately, the new planet remains unreachable in the dark borders of our solar system.

00:25:05 Enthusiasts are still convinced of its existence

00:25:08 and think that it is only a matter of time before we celebrate the discovery of a new neighbor.

00:25:14 They are hoping for the Vera S. Rubin Observatory,

00:25:18 which is currently under construction in Chile

00:25:20 and should be fully operational by the end of 2025.

00:25:24 Over the next 10 years, this observatory will sweep the entire sky of the southern hemisphere

00:25:29 every few nights with an 8-meter telescope

00:25:32 equipped with the largest digital camera in the world.

00:25:35 The idea is to catalog the entire solar system, beyond Neptune,

00:25:39 and to track the movements of millions of celestial objects,

00:25:42 including space debris, asteroids, comets and other stars.

00:25:47 If the new planet is actually there,

00:25:50 this new generation telescope could be the one that will succeed.

00:25:54 The existence of this mysterious planet is far from being accepted by the entire scientific community.

00:26:02 It is simply because the new planet is not the only explanation

00:26:06 for the strange phenomena that occur on the part of Neptune.

00:26:09 One theory suggests that a group of distant objects, such as dwarf planets, comets or moons,

00:26:14 could collectively influence the orbits of the extreme trans-Neptunian objects.

00:26:19 Others believe that a black hole would be the origin of all this.

00:26:23 These ultra-compressed masses are among the densest objects in the universe,

00:26:27 potentially capable of affecting the orbits of other objects,

00:26:30 as is supposed for this ghostly new planet.

00:26:36 Another bold theory suggests that our current understanding of the laws of gravity

00:26:41 would be wrong, or rather incomplete.

00:26:44 The latter, known as modified Newtonian dynamics,

00:26:48 suggests that these distant frozen objects exhibit this strange behavior,

00:26:52 not because of the interference of another planet,

00:26:54 but rather because the immense gravitational field of the Milky Way influences them.

00:26:59 However, even the supporters of this theory recognize that it is too early

00:27:04 to draw definitive conclusions from it,

00:27:06 and much more in-depth research is still necessary.

00:27:10 As we continue our search for the new planet,

00:27:15 some astronomers have gone even further,

00:27:17 suggesting the existence of a hypothetical planet of X.

00:27:20 It would have a mass and a size similar to that of Mars or Earth,

00:27:24 and would be at the edge of Kuiper Belt.

00:27:27 But here's the thing.

00:27:30 If this supposed planet of X is actually as small as scientists think,

00:27:35 it could not have enough gravity to clear its orbit of the surrounding debris.

00:27:41 And it's quite similar to what's happening with Pluto.

00:27:44 This is one of the reasons why it was retrograded in 2006.

00:27:49 So, indeed, it's better not to get too carried away.

00:27:52 This alleged planet of X could end up being classified as another dwarf planet.

00:27:58 The Earth is not flat, but Jupiter could have been.

00:28:01 Instead of big round spheres,

00:28:03 the gas giants of our solar system may have started their lives as simple crepes.

00:28:08 Jupiter is one of our oldest neighbors.

00:28:11 It is 4.6 billion years old, just like our Sun.

00:28:14 And when it was still young, it probably formed in a protoplanetary disk.

00:28:19 Everything starts with stars.

00:28:23 When a star is still forming, it does not look like a round object.

00:28:27 It's more like a big disk of matter.

00:28:29 At this stage, hot winds blow, composed of charged particles.

00:28:33 The dust of this disk contains elements like carbon and iron.

00:28:38 Some of them collide and remain together, forming larger objects.

00:28:43 The dust turns into pebbles, the pebbles turn into rocks,

00:28:47 and the rocks hit each other, becoming bigger and bigger.

00:28:52 The gas in the disk helps all these solid pieces to agglutinate.

00:28:56 Some detach, but others remain together.

00:28:59 And they are the ones that become the basis of the planets.

00:29:02 They are called planetesimals.

00:29:04 Even gas giants like Jupiter started as tiny dust particles,

00:29:09 smaller than a human hair.

00:29:12 Finally, they formed their own disk of matter.

00:29:15 Then, they started to spin around our Sun,

00:29:19 growing as they accumulated gas and rocks, like a big snowball.

00:29:24 The gas giants are special.

00:29:27 They are born from the coldest parts of the disk.

00:29:31 In these cold regions, the molecules are slower,

00:29:34 making them easier to capture.

00:29:37 The water can freeze, and tiny pieces of ice stick together and mix with dust.

00:29:43 These snowballs then form the cores of vast planets like Jupiter, Saturn, Uranus and Neptune.

00:29:52 In the warmer regions, near the star,

00:29:55 teluric planets like Mercury, Venus, Earth and Mars start to form.

00:30:01 After the birth of the ice giants,

00:30:03 there was not much gas left for these tiny celestial bodies,

00:30:06 and it could take tens of millions of years for such planets to form after the birth of a star.

00:30:12 Our Sun was growing at the same time,

00:30:15 sucking in the gas close by and pushing the distant objects even further.

00:30:19 After billions of years, the disk completely changed,

00:30:23 transforming into a spherical star with a bunch of giant and tiny planets,

00:30:27 asteroids, moons, meteorites and comets around it.

00:30:33 Recently, simulations have shown that these proto-planets,

00:30:39 as we call their first dust conglomerates,

00:30:42 did not start by looking like the planets we know.

00:30:45 In the case of gas giants like Jupiter,

00:30:48 they would look more like crushed balls or M&Ms.

00:30:52 When the Sun was still young,

00:30:54 the gas and dust disk surrounding it cooled down and became unstable.

00:30:59 It started to break into large pieces.

00:31:02 These gathered under the effect of an implacable gravity to create Jupiter.

00:31:07 Then it became a spherical gas giant over time.

00:31:11 Numerous anomalies can occur during this process of planet formation.

00:31:15 Have you ever wondered why Venus or Uranus were rotating in the opposite direction?

00:31:20 Usually, when things are formed from a rotating gas disk,

00:31:25 they tend to rotate in the same direction.

00:31:28 If you rotate a bunch of balls tied to a string, for example,

00:31:32 they will all rotate in the same way.

00:31:34 So, theoretically, all planets should also rotate in the same direction.

00:31:40 But there are also many objects that move quickly in our solar system,

00:31:44 like comets and asteroids.

00:31:46 When they collide with planets, especially during their first days,

00:31:50 this impact can lead them to rotate in the opposite direction.

00:31:54 Venus and Uranus probably survived a large-scale collision.

00:31:58 Fortunately, they were not ejected into the distant space.

00:32:01 The gravity of the Sun and neighboring planets kept them in their place.

00:32:06 There are also what are called gravitationally locked planets.

00:32:13 These are celestial bodies that rotate so that one side is always facing their star,

00:32:19 while the other remains in perpetual darkness.

00:32:22 Thus, one side is always very hot, while the other is extremely cold.

00:32:26 If we lived on such a planet, we could only exist on a thin band between these two extremes.

00:32:32 These planets form when they are very close to their star.

00:32:36 The gravitational forces at work are intense and, over time,

00:32:40 slow down the rotation of the planet until it corresponds to the time it takes to orbit around its star.

00:32:47 Imagine that you are turning on your chair.

00:32:49 Someone approaches you and, holding your chair in his hands, starts to turn with you.

00:32:54 In this way, you will face each other all the time.

00:32:57 Synchronous rotation planets work a little like this.

00:33:01 Our Moon is also in synchronous rotation with the Earth.

00:33:05 That's why we only see one side of it.

00:33:09 We have discovered more than 5,000 exoplanets outside our solar system.

00:33:14 Some of them have very strange orbits.

00:33:17 There are some, for example, that have incredibly long orbits,

00:33:21 thousands of years to make a single revolution around their star.

00:33:25 Or very unequal orbits, similar to those of comets.

00:33:29 Or those planets that are called "hot Jupiters",

00:33:32 which are very close to their star, much closer than Mercury is to our Sun.

00:33:37 But these planets could not have formed where they are now.

00:33:41 As their solar system evolved, they, for one reason or another, changed positions.

00:33:47 This rearrangement is called "planetary migration".

00:33:51 There are three ways this migration can occur.

00:33:56 First, due to the gas and dust in rotation around the planet.

00:34:01 When a planet collides with this matter,

00:34:04 it can create spiral patterns in the gas.

00:34:07 These patterns can either bring the planet closer to the center,

00:34:10 or move it away, depending on how they mix.

00:34:13 This is called a "type I" migration.

00:34:16 This is what Jupiter experienced when it came closer to the Sun billions of years ago.

00:34:21 And this also explains the existence of "hot Jupiters".

00:34:25 Secondly, large planets can shake the smallest ones, changing their trajectory.

00:34:31 And thirdly, the gravity of the star can attract the planet, making its orbit circular.

00:34:37 Have you ever heard of wandering planets?

00:34:43 Imagine a lonely planet, floating in the vastness of space,

00:34:47 without being attached to any star.

00:34:50 These are the wandering nomads of our galaxy, condemned to wander eternally.

00:34:54 And there are so many of them!

00:34:56 There could be more planets in freedom than planets linked to a star.

00:35:00 We are talking about thousands of billions of wandering bodies in our Milky Way.

00:35:06 It is not uncommon for them to be as massive as our largest planet, Jupiter.

00:35:11 But most of them would be a size more comparable to that of the Earth.

00:35:15 There are even some that could have a thick atmosphere capable of keeping them warm.

00:35:19 Although they are far from all stars,

00:35:21 some of these planets may have auroras to cover their souls,

00:35:25 while others may be in the orbit of moons containing liquid lead,

00:35:29 or have potential for life.

00:35:31 There is even a chance that they may inhabit an extraterrestrial life.

00:35:35 These planets could be hit by other stars,

00:35:37 or even entire planetary systems during their crazy races through space.

00:35:41 Sometimes, they can be captured by the gravity of a star for a certain time,

00:35:45 before being ejected back into space.

00:35:48 But how do they come to be?

00:35:50 Sometimes, during this chaotic formation process,

00:35:53 all the planets fail to stay close to their star-like relatives.

00:35:57 Some of them are expelled from their solar system

00:36:00 due to the gravitational attraction of other planets,

00:36:04 or passing stars.

00:36:06 These ejected planets then become wandering planets.

00:36:10 In 2012, astronomers discovered a solar system dating from the beginning of the universe.

00:36:17 This system includes a star and two planets.

00:36:20 It was nicknamed the "fossil system".

00:36:23 Its star is incredibly old,

00:36:26 about 13 billion years old,

00:36:28 almost as old as our universe itself.

00:36:32 This system is mainly composed of hydrogen and helium.

00:36:35 This is unusual, because planets are generally formed

00:36:38 from gas clouds containing heavier elements.

00:36:42 It was then that we understood that the way planets were formed before

00:36:46 was different from the way they are formed today.

00:36:50 We know that the stars containing the most metals

00:36:53 are the most likely to have planets.

00:36:55 In astronomical terms, "metaux" means any chemical element

00:36:59 other than hydrogen and helium.

00:37:02 But in the primitive universe, there were not many heavy elements.

00:37:06 Most of them were created inside the stars

00:37:09 and then dispersed in space when they exploded.

00:37:13 So, when did the very first planets form?

00:37:17 This newly discovered system helps to answer this question.

00:37:21 These two giant planets are orbiting around a star,

00:37:24 which is incredibly poor in metals and extremely old.

00:37:28 This should be very rare, if not impossible,

00:37:31 but they exist, nevertheless.

00:37:33 This may mean that there are more planets in poor metal systems

00:37:37 than we thought.

00:37:38 The students will help us learn more about the formation of planets.

00:37:43 If you want to travel in space,

00:37:47 prepare to spend about 55 million dollars.

00:37:51 But in the near future, you will probably be able to travel in space

00:37:55 by simply pressing a button without ruining yourself.

00:37:58 Because space elevators could be a good option.

00:38:01 While the idea of a galactic elevator seems to come from a science fiction movie,

00:38:06 it is a real possibility that could revolutionize space travel.

00:38:10 With an estimated cost of 8 billion dollars,

00:38:13 such an elevator could only represent a single investment

00:38:16 that would last us forever.

00:38:20 NASA alone spends about 2.7 million dollars

00:38:25 on rocket fuel every minute of flight.

00:38:28 To launch a rocket, they must spend up to 178 million dollars.

00:38:33 These costs could be considerably reduced if we used elevators.

00:38:38 Most of the tallest buildings on Earth

00:38:40 have massive foundations to help balance their weight.

00:38:44 The more you look up in the air, the more they shrink.

00:38:47 Even the highest skyscraper in the world, the Burj Khalifa,

00:38:51 is thick at its base and thin at its top.

00:38:54 If we wanted to build something that looks like a gigantic elevator,

00:38:59 we would need a huge amount of concrete to build the foundations.

00:39:04 Which goes against our original goal of saving money.

00:39:08 Now, take a string, attach a ball to its end,

00:39:12 and start spinning it.

00:39:14 The string in your hand will stay in place,

00:39:17 and the ball will spin around your hand.

00:39:19 This is called centrifugal force.

00:39:21 And the elevator will work the same way.

00:39:24 The ball will be a base in space,

00:39:26 and the rope will pull it to Earth.

00:39:28 The station through which we would enter the elevator

00:39:34 would be in the middle of the Atlantic Ocean,

00:39:36 and the cable would extend from there.

00:39:39 To make this possible,

00:39:41 the cable must be perfectly synchronized with the rotation of the Earth.

00:39:45 Otherwise, it will simply break or roll around the Earth like a whip.

00:39:50 In addition, the orbit followed by the cable should form a perfect circle,

00:39:55 because the line could neither shorten nor extend.

00:39:58 Many calculations have been made to find the ideal solution.

00:40:02 Wait a minute.

00:40:03 Is this what algebra is for?

00:40:05 Who would have thought?

00:40:07 In the meantime, we will not bore you with more mathematics.

00:40:11 Let's address directly the precise distance between the Atlantic Station

00:40:15 and the one in space,

00:40:17 which must be 36,000 km above the Earth,

00:40:20 where the geosynchronous orbit begins.

00:40:23 There, the four ascending forces are much stronger than the only descending force.

00:40:30 This is why the station would remain in place.

00:40:33 When you build a house or a building,

00:40:36 you must start from the bottom and progress upwards.

00:40:39 But to create this marvel of engineering,

00:40:41 we would need to go the other way around and start from the top.

00:40:46 The main problem here would be the weight.

00:40:50 If the line was too heavy, it would disturb the orbit,

00:40:53 and the loader would not work.

00:40:56 We would therefore need to balance the space station

00:40:59 to ensure a flawless operation.

00:41:04 Steel is one of the most robust materials on Earth.

00:41:08 The cable of each elevator is made of steel.

00:41:11 But when you need a cable 36,000 km long,

00:41:15 things can get a little complicated.

00:41:18 Steel is difficult to break, but it is bulky.

00:41:21 And when you have to use a lot of it,

00:41:23 that's when the problems start to arise.

00:41:27 We use a lot of steel in construction,

00:41:30 but we have lighter materials at our disposal

00:41:33 that could reduce the strain on the station and eliminate this problem.

00:41:37 In addition, the cable should be fused,

00:41:40 because at the end, the constraint would be virtually non-existent.

00:41:44 But it should always be thicker than necessary

00:41:47 due to many safety factors.

00:41:50 At first, the cable would be barely more than 1 mm thick.

00:41:54 After a lot of complicated calculations,

00:41:56 we can determine its size at the end of the race,

00:41:59 which is a number so long that we would be unable to pronounce it.

00:42:03 But believe us, it's a very, very big number.

00:42:06 So steel is out of the question.

00:42:09 Another candidate is Kevlar, which is five times more resistant than steel.

00:42:13 And if we added materials such as carbon and titanium to this alloy,

00:42:17 its resistance would still be doubled.

00:42:20 The cable would then have a diameter between 80 and 170 m.

00:42:24 That's much smaller than the diameter of a similar steel cable.

00:42:29 The bad news is that it would cost far too much.

00:42:33 So if we don't find the ideal material to build this cable,

00:42:37 the very idea of a space elevator will never be a vast waste of time.

00:42:42 If only we had a light, miraculous material at our disposal,

00:42:49 capable of taking in a pressure of 60 GPa,

00:42:52 and which also had a conicity ratio of 1.6.

00:42:56 Oh, but wait, we do have such a material.

00:43:00 It's what we call carbon nanotubes.

00:43:03 They have a resistance of 130 GPa,

00:43:06 which is much more than we need.

00:43:10 Nanotubes are made from carbon,

00:43:13 and are 100,000 times thinner than human hair.

00:43:16 This material is solid and has a good conductivity,

00:43:19 which is made possible by its unique atomic structure.

00:43:23 We use this innovation in many things,

00:43:26 from batteries to optics,

00:43:28 and they can be completely modified and adapted to many other uses.

00:43:33 Bradley Edwards is the man responsible for this idea.

00:43:37 NASA was looking for new innovations, and told him,

00:43:40 "Don't try anything crazy and just start building a space elevator."

00:43:44 We suppose Bradley had to take this as a challenge,

00:43:47 because he had started working on the elevator.

00:43:50 Edwards therefore wrote an article on a galactic transporter.

00:43:54 When he published it, he expected many experts to disavow the flaws in his work.

00:43:59 But surprisingly, no one did.

00:44:02 His concept was irreproachable.

00:44:05 He thus had the idea of attaching a line of nanotubes to a rocket,

00:44:09 and propelling it into space.

00:44:11 The other end of the cable would fall back to Earth,

00:44:14 and robots would use it to climb and stretch it,

00:44:18 so that we could start building a space station.

00:44:21 After that, the elevator could start to run everything and anything,

00:44:26 from solar panels to tourists.

00:44:28 In the future, space tourism could become accessible.

00:44:32 Who knows, we could even go on vacation in space one day.

00:44:35 Hey, are you looking for an escape atmosphere?

00:44:38 Well, don't come here, we don't have any.

00:44:41 Oops, probably not the best advertising slogan, is it?

00:44:45 A few years ago, we could only create nanotubes of microscopic carbon,

00:44:50 but over time, more research has been done to make them bigger.

00:44:55 Today, they reach a few centimeters.

00:44:58 In 20 years, they could be several kilometers long.

00:45:02 Carbon costs $ 1 a gram.

00:45:05 If we did the math, we would see that it would take us about $ 1 billion

00:45:09 to build this elevator.

00:45:11 Yes, it seems expensive, but it's a long-term solution for space travel,

00:45:15 which could save us a lot of money.

00:45:18 Everything seems perfect on paper.

00:45:21 But the main reason why NASA chose not to pursue this project

00:45:26 is that at the moment, there are probably more than 128 million debris

00:45:30 floating in the Earth's orbit,

00:45:32 and it could pose a real threat to this elevator.

00:45:36 It could, of course, be designed to withstand a few impacts from time to time,

00:45:42 but being constantly bombed was not part of the equation.

00:45:45 Nevertheless, Bradley supports that a fleet of surveillance devices detects these space debris.

00:45:51 Thus, the elevator could be able to avoid them all.

00:45:55 If something hit the elevator, or if the cable broke one way or another,

00:46:02 the consequences would not be too severe.

00:46:04 Finally, if there were no passengers on board, of course.

00:46:08 If the line was cut, the elevator would simply drift into space

00:46:12 and would not pose any threat to anyone.

00:46:15 In Japan, engineers are trying to build a space elevator.

00:46:20 This one could also be used for mining in space.

00:46:25 We could easily cover the cost of this elevator by catching asteroids on the way,

00:46:29 because some of them are made of precious metals.

00:46:32 We could then exploit them and quickly repatriate them to Earth.

00:46:36 1994. It was getting dark.

00:46:41 So that no one noticed the two silhouettes opening the emergency exits

00:46:45 of a glass dome complex located in Arizona and known as Biosphere 2.

00:46:50 They were determined to free seven people locked up inside for a month,

00:46:55 risking their lives in the name of science.

00:46:57 The mission was a success,

00:46:59 but they were accused of property violation and vandalism.

00:47:03 The vandals were Tabiga El-Hallin and Mark Vantillo.

00:47:06 They were among the first eight unfortunate people to live in this place, like guinea pigs.

00:47:11 And they didn't want others to suffer the same horrors they had experienced.

00:47:15 $150 million has been spent to determine

00:47:18 whether humans could create suitable living conditions on other planets, like Mars.

00:47:23 To do this, scientists built a mini world with more than 3,000 species of plants and animals.

00:47:29 Biosphere 2 was a 12,000 square meters habitat,

00:47:32 completely isolated, with its own mini tropical forest,

00:47:36 a private beach with a coral reef, a small savannah, a swamp, and even a piece of desert.

00:47:42 Between 1991 and 1993, nothing could enter or leave this place.

00:47:48 The group of eight people locked up inside were called the Biospherians.

00:47:52 They wore suits like Star Trek,

00:47:55 growing their own food and breathing their own air.

00:47:59 Everything started with great hope and a breakfast worthy of a five-star hotel.

00:48:04 But things got darker over the months.

00:48:07 The whole team was starving and went on a hunger strike.

00:48:10 In Biosphere 1, which is our good old Earth,

00:48:13 you can order a pizza in two minutes.

00:48:16 But inside Biosphere 2, they had to spend four endless months preparing a margherita.

00:48:21 They had to harvest wheat for the dough and goat's milk for the cheese.

00:48:25 The goal was to be completely self-sufficient,

00:48:28 and they became an integral part of their atmosphere, literally.

00:48:32 When they exhaled, their carbon dioxide fed the sweet potatoes they were growing.

00:48:37 And these sweet potatoes became, in return, a part of themselves,

00:48:41 since they were eating essentially the same carbon over and over again.

00:48:45 They ate so much sweet potatoes that their skin actually turned orange

00:48:49 because of all this excess beta-carotene.

00:48:52 What seemed to be a fun situation at the time,

00:48:55 turned out to be a big problem.

00:48:57 The agricultural yields in Biosphere 2 were extremely disappointing.

00:49:01 And the team was starving.

00:49:03 Hunger drove them crazy, and sudden anger attacks led them to do regrettable things,

00:49:08 like stealing bananas in the basement.

00:49:11 After a while, they had to lock the freezer.

00:49:14 During the first six months, each of them lost between 8 and 26 kilos.

00:49:18 Every day, someone weighed the fresh food for the chef,

00:49:22 providing all the information on the nutrients in the computer,

00:49:26 to make sure that the crew reached its recommended yields in calories, protein and fat.

00:49:32 At first, meals were served in the form of buffets.

00:49:35 But as the food began to run out,

00:49:38 the chefs began to meticulously divide their food into equal portions.

00:49:43 Their diet, mainly sweet potatoes, carrots, fruits,

00:49:47 and occasionally meat on Sundays,

00:49:49 was supposed to allow them to hold out during these exhausting 80-hour weeks,

00:49:53 made of exhausting manual work.

00:49:55 The Biosphere team left each meal still hungry,

00:49:58 and had recurring dreams of Big Mac,

00:50:01 sushi, chocolate bars, and other cakes.

00:50:04 The air was starting to run out.

00:50:06 The place was completely sealed,

00:50:08 with a glass dome and steel at the top,

00:50:10 and a floor made of the same metal at the bottom.

00:50:13 The managers made sure to control everything that entered,

00:50:16 to prevent synthetic materials from emitting harmful gases.

00:50:20 The comfort areas were fenced with wood and wool,

00:50:23 and no chemical deodorant or birthday candles could be used there.

00:50:28 The Biosphere team relied on the food they grew,

00:50:32 and on their mini tropical forest,

00:50:34 to produce the oxygen necessary for their survival.

00:50:36 However, they were losing oxygen very quickly,

00:50:39 suffocated by their own carbon dioxide emissions.

00:50:43 And the worst part was that they had no idea why.

00:50:46 With another 9 months of experience to endure,

00:50:49 the oxygen level had already dropped from 21 to about 15%,

00:50:53 which gave the impression of living at the top of Mount Fuji.

00:50:57 They felt terribly sick,

00:50:59 and dragged themselves painfully through the Biosphere.

00:51:02 They couldn't even finish a sentence without stopping to catch their breath.

00:51:06 Then the apnea of sleep began to appear,

00:51:09 some waking up out of breath.

00:51:11 To reduce the CO2 levels inside the Biosphere 2,

00:51:14 they tried a few desperate maneuvers,

00:51:17 like pushing plants at a crazy pace,

00:51:19 reducing the soil water as much as possible,

00:51:22 and even giving up plowing their crops.

00:51:25 Nothing worked.

00:51:26 Everyone agreed that they were not far from the bottom.

00:51:29 And so they decided to ask for help.

00:51:32 Refrigerated trucks arrived to pump pure oxygen into Biosphere 2.

00:51:36 As soon as the gas began to spread,

00:51:38 they started laughing out loud, and running around like crazy.

00:51:42 The ecosystem was a real disaster.

00:51:44 The hummingbirds and bees disappeared after a few months,

00:51:47 so that the plants were no longer pollinated.

00:51:50 The greens and the acarians attacked the crops.

00:51:52 And the cockroaches invaded everything.

00:51:55 Four species of cockroaches were introduced to recycle organic matter,

00:51:59 but the ordinary domestic cockroaches were the ultimate survivors.

00:52:03 They managed to infiltrate and multiply,

00:52:06 posing a serious threat to the crops.

00:52:09 At night, the kitchen was full of cockroaches as soon as the lights went out.

00:52:13 To fight this infestation,

00:52:15 the group greased coffee cups with lubricant,

00:52:18 and put pieces of papaya in them to serve as a starter.

00:52:21 The cockroaches climbed inside,

00:52:23 but could no longer climb the sliding edges to escape.

00:52:27 Being hungry, lacking oxygen,

00:52:29 facing insect infestations,

00:52:31 it would be enough to drive anyone crazy.

00:52:34 Violent disputes led people to throw cups at each other,

00:52:38 and spit on each other.

00:52:40 In the end, the group simply split in two.

00:52:43 They stopped talking to each other,

00:52:45 and could meet in the corridors without even looking at each other.

00:52:48 Half of them wanted more food and oxygen

00:52:51 to continue the experiment with dignity,

00:52:53 while the other half believed in their chance of survival without external help,

00:52:57 and whatever it cost.

00:52:59 In truth, the sealed room had been violated long before all this.

00:53:03 Just two weeks after their entry,

00:53:05 a biospheric woman named Jane Pointer

00:53:08 cut her finger in a kitchen accident while preparing rice.

00:53:12 The doctor on the mission tried to sew it back together,

00:53:14 but it didn't work, and her finger turned black in a few days.

00:53:18 She went to an outside hospital to be operated on,

00:53:21 and a few hours later,

00:53:23 she returned inside with a bag of sports filled with equipment

00:53:26 like computer parts and colored films.

00:53:30 The journalists only discovered this stealth delivery many months later,

00:53:34 and because of this,

00:53:36 many people questioned the credibility of the entire experiment.

00:53:40 The media treated the experiment as a reality TV show,

00:53:44 calling it "ecological entertainment in fashion".

00:53:47 The big titles from all over the world

00:53:49 seemed like the team was about to give up on it,

00:53:52 to the point that their families were worried,

00:53:55 and kept calling the biospheric people to make sure they were doing well.

00:53:59 The group seemed to be in a human zoo,

00:54:02 with tourists coming from far away to watch them through their glass cage.

00:54:06 In just the first six months,

00:54:08 more than 150,000 people visited the place.

00:54:12 Biosphere 2 ended up becoming a gag in popular culture,

00:54:15 inspired by a comedy called "Biodome"

00:54:18 and decades of funny sketches.

00:54:20 You may be wondering why none of them gave up the experiment

00:54:23 and didn't go out the front door.

00:54:25 Well, none of the environmentalists

00:54:27 wanted to be the first to admit it was beyond their strength.

00:54:31 In addition, they all still kept the hope

00:54:34 of being able to face the challenge of building a second Earth.

00:54:38 In the end, they managed to discover where the 7 tons of oxygen was missing.

00:54:43 It had been absorbed by the concrete.

00:54:46 Even if being out of breath all the time

00:54:48 may seem to have been the biggest challenge they had to face,

00:54:51 the biospheric people declared that learning human contact

00:54:54 in a closed environment was even more difficult.

00:54:57 It seems that the experiment was a huge fiasco,

00:55:00 but the group has learned a lot of valuable lessons.

00:55:03 They have proven that a sealed ecosystem could work for years.

00:55:06 They have contributed to studies on coral reefs restoration.

00:55:10 And their farm has shown that a high yield

00:55:13 and a complete recycling of nutrients

00:55:15 could be achieved without the help of chemical products.

00:55:18 In case you were wondering,

00:55:20 it wasn't the end of the glass complex.

00:55:23 The second mission inside Biosphere 2

00:55:26 took place in March 1994.

00:55:28 Now, you can go back to the beginning of the video

00:55:31 to understand how it could have happened for them.

00:55:34 If an asteroid like Apophis hit the Earth,

00:55:38 we would be destroyed.

00:55:40 Huge earthquakes shook the Earth

00:55:43 and tsunamis flooded everything.

00:55:46 Apophis, a celestial body several billion years old,

00:55:50 has been present in the solar system since its creation.

00:55:53 You are probably wondering what is the probability

00:55:56 that this gigantic stone will collide with our planet in 2029.

00:56:00 Well, we'll see that, okay?

00:56:03 Apophis is a huge asteroid discovered in 2004

00:56:08 by the National Kitt Peak Observatory in Arizona.

00:56:11 Since then, it has been said to be one of the most dangerous asteroids

00:56:16 ever located.

00:56:18 It is about 330 meters wide.

00:56:21 It's a little bigger than the Empire State Building or the Eiffel Tower.

00:56:24 It's because it's so scary that it was named Apophis,

00:56:29 after the Egyptian immortal creature

00:56:31 that brought eternal darkness and destruction.

00:56:34 In 2021, researchers had the exceptional opportunity

00:56:39 to study this floating rock

00:56:41 when it passed near our planet.

00:56:43 We'll get back to that in a minute.

00:56:46 Some scientists say that there is a 2.7% chance

00:56:50 that Apophis will hit Earth on Friday, April 13, 2029.

00:56:54 It would be the Yarkovsky effect that would be at risk

00:56:58 because it would push this big space rock towards Earth.

00:57:01 This effect comes from the unequal emission of thermal photons,

00:57:06 whose result is an unimaginable force

00:57:09 exerted on the object affected.

00:57:11 These photons exert a huge thrust

00:57:14 and play an essential role in the dynamics of the body in question.

00:57:17 The asteroid has two faces, a dark one and a light one,

00:57:22 just like the Moon.

00:57:23 The light side is facing the Sun

00:57:25 and is warmer than the dark side.

00:57:27 But the object rotates itself,

00:57:29 so that its faces constantly change direction and temperature.

00:57:33 These changes are not good

00:57:35 because they push Apophis slightly towards Earth.

00:57:38 Unfortunately, no one knows how the Yarkovsky effect

00:57:42 will affect the trajectory of the asteroid.

00:57:45 On the other hand,

00:57:46 during the last asteroid pass near Earth in 2021,

00:57:50 astronomers used radars to take precise measurements of its trajectory

00:57:55 and they were able to conclude that Apophis

00:57:57 will pass at about 3,000,000 km from Earth in 2029

00:58:01 and will not disturb us for at least 100 years.

00:58:05 In general, every 8,000 years,

00:58:08 our planet is hit by a shooting star of dimensions similar to that of Apophis.

00:58:13 The last time we were hit by a slightly smaller meteor,

00:58:18 it was in 2013.

00:58:19 A new spacecraft developed by NASA,

00:58:25 called Osiris-Rex,

00:58:26 was launched in 2016 to collect samples

00:58:29 on another slightly less terrifying celestial body,

00:58:32 Bennu.

00:58:33 Four years later,

00:58:35 it finally reached the target object,

00:58:37 took some samples,

00:58:39 quickly said goodbye to Bennu

00:58:41 and returned to Earth.

00:58:43 The samples were safely stored in a capsule deposited in Utah.

00:58:47 So far,

00:58:49 this is the most significant sample ever taken on an asteroid.

00:58:53 After its delivery,

00:58:54 the ship did not waste time

00:58:55 and set off to pursue Apophis.

00:58:58 For this mission,

00:58:59 Osiris-Rex was renamed Osiris-Apex

00:59:02 and it is currently playing Hachat with Apophis.

00:59:06 With a little luck,

00:59:07 on April 2, 2029,

00:59:09 when the asteroid passes near Earth,

00:59:12 the space probe will reach Apophis to land there.

00:59:15 It will stay on it for 18 months,

00:59:18 collecting precious information

00:59:20 and taking thousands of photos.

00:59:22 The asteroid will be monitored with powerful telescopes.

00:59:27 At some point,

00:59:29 Apophis will be too close to the sun

00:59:31 and it is then Osiris-Apex

00:59:33 that will take care of monitoring it.

00:59:36 If you live in Europe,

00:59:37 West Asia or Africa,

00:59:39 you are among the lucky ones

00:59:41 who will have the unique opportunity

00:59:43 in a life to see Apophis with the naked eye.

00:59:45 It will be visible in the sky of these regions in 2029

00:59:50 and those who have telescopes

00:59:52 will be able to see it again in 2036.

00:59:55 Osiris-Apex will certainly encounter some problems,

01:00:00 because the asteroid has a thick crust

01:00:02 and the spacecraft will not be able to collect data

01:00:05 as easily as on Bennu.

01:00:07 Osiris-Apex has a single propeller

01:00:09 that will blow all the dust of Apophis

01:00:12 when it lands.

01:00:13 It will be a perfect opportunity

01:00:15 to analyze the surface of the asteroid

01:00:17 and see what it is made of.

01:00:19 The probe will spend a year and a half

01:00:21 mapping the asteroid

01:00:23 trying to detect changes in its shape.

01:00:25 All these researches will show

01:00:27 how the celestial body moves

01:00:29 and we will have a better idea

01:00:31 of how to protect our planet from such objects.

01:00:33 In 2025, NASA will also launch

01:00:35 the Apophis Pathfinder mission

01:00:37 and it will be the first space ship

01:00:39 to ever touch this asteroid.

01:00:41 It will land about a year after its launch.

01:00:45 In addition, NASA has proposed

01:00:47 to send a small-scale test

01:00:49 to allow humanity to develop

01:00:51 effective protection tactics

01:00:53 against asteroid impacts.

01:00:55 We know that Apophis comes from the main asteroid belt

01:00:59 located between Mars and Jupiter.

01:01:01 Over the last million years,

01:01:04 this celestial body has changed its trajectory

01:01:06 due to the considerable influence

01:01:08 of Jupiter's gravity.

01:01:10 Now, it seems to favor the Sun more,

01:01:12 which means that this asteroid

01:01:14 is very close to Earth.

01:01:16 That's why it's ranked among the celestial bodies

01:01:18 neighboring our planet.

01:01:20 Many tests have been carried out

01:01:22 to find a way to take care of these asteroids.

01:01:24 Among the solutions,

01:01:26 there is drilling and detonation

01:01:28 of the inner space.

01:01:30 But we are also testing new technologies,

01:01:32 such as attaching rockets

01:01:34 to redirect the harmful object away from Earth.

01:01:36 We could also hit it

01:01:38 with a sufficiently powerful force

01:01:40 to change its direction.

01:01:42 Apophis is an asteroid of type S

01:01:44 composed of rocks and metals,

01:01:46 iron, nickel, etc.,

01:01:48 and that looks like a peanut.

01:01:50 It can teach us a lot about the past

01:01:52 and also about the future.

01:01:54 The samples collected can reveal

01:01:56 how the plants appeared.

01:01:58 Many theories suggest

01:02:00 that water came to our planet

01:02:02 thanks to an asteroid or a comet.

01:02:04 Asteroids are like

01:02:06 precious time capsules.

01:02:08 Unlike terrestrial rocks,

01:02:10 which have undergone countless changes,

01:02:12 such as erosion, most celestial bodies

01:02:14 are intact and much easier to study.

01:02:16 When meteors fall on Earth,

01:02:18 they are covered with debris

01:02:20 that is impossible to clean.

01:02:22 That's why it's so important

01:02:24 to study Apophis right now.

01:02:26 In addition,

01:02:28 some asteroids are made of precious metals,

01:02:30 such as platinum.

01:02:32 At the moment, we have a strong demand

01:02:34 for metals for the industry,

01:02:36 and mining on Earth

01:02:38 is quite difficult.

01:02:40 A single big meteor could provide us

01:02:42 with iron, nickel, gold, and platinum

01:02:44 for millions of years.

01:02:46 If Apophis contains all these metals,

01:02:48 we will have to decompose it

01:02:50 and bring it back to Earth.

01:02:52 A single asteroid could cost billions of dollars.

01:02:54 Space mining

01:02:56 would be extremely profitable.

01:02:58 However, it would cost us more

01:03:00 to bring it back to Earth

01:03:02 than to extract its materials here.

01:03:04 With the technological progress

01:03:06 and the development of new types of rockets,

01:03:08 it may be possible

01:03:10 one day.

01:03:12 So,

01:03:14 even if we have nothing to fear

01:03:16 from Apophis for another hundred years,

01:03:18 we still need to know

01:03:20 what would happen

01:03:22 if such an impact occurred.

01:03:24 Come on, admit it, you want to know.

01:03:26 Well, let me tell you

01:03:28 that you would hear a huge noise

01:03:30 and that you would know that a disaster

01:03:32 has even reached kilometers away.

01:03:34 You would have to leave your home immediately.

01:03:36 Shortly after the impact,

01:03:38 violent earthquakes would occur

01:03:40 and buildings would fall like themselves.

01:03:42 Staying away from cities

01:03:44 would probably be the best thing to do.

01:03:46 But you should not run away by car.

01:03:48 There would be huge traffic jams

01:03:50 and everyone would panic.

01:03:52 You moving on foot or by bike

01:03:54 would be your best option in this scenario.

01:03:56 A privileged means of transport

01:03:58 would be the plane.

01:04:00 So, if you have always dreamed

01:04:02 of obtaining your pilot's license,

01:04:04 you now have a good excuse.

01:04:06 You would also need to take

01:04:08 enough food and drink

01:04:10 and a pair of socks in addition.

01:04:12 Living near the ocean or the sea

01:04:14 is pleasant, but in this scenario

01:04:16 there would be no worse place.

01:04:18 Huge waves would hit the coast

01:04:20 after the impact.

01:04:22 Far from the impact area,

01:04:24 tsunamis could take up to 30 hours

01:04:26 to arrive.

01:04:28 It would give you some time to prepare.

01:04:30 We still can't find

01:04:34 the origin of the mysterious signal

01:04:36 that has been reaching us since 2018.

01:04:38 We receive it every 22 minutes

01:04:42 and nothing can explain it.

01:04:44 Some scientists even think

01:04:46 it could come from an alien civilization

01:04:48 that we haven't yet encountered.

01:04:50 This strange radio signal

01:04:58 was not discovered by a researcher

01:05:00 during a serious mission.

01:05:02 To be honest, it was noticed

01:05:04 by a student who was simply working

01:05:06 on an ordinary project in the context of his studies.

01:05:08 Tyrone O'Doherty,

01:05:10 a first-cycle student at the Curtin University

01:05:12 in Australia, was going through

01:05:14 old data from the Australian VOOT.

01:05:16 He was looking for any intermittent radio signals

01:05:18 when he finally came across

01:05:20 a signal dating from 2018

01:05:22 and which seemed to emit radio waves

01:05:24 towards the Earth, like a lighthouse.

01:05:26 Enthusiastic about his discovery,

01:05:28 Tyrone shared it with his mentor,

01:05:30 radio astronomer

01:05:32 Natasha Hurley Walker.

01:05:34 She dove into the search for this signal

01:05:36 in search of a scientific breakthrough.

01:05:38 But despite the examination of different frequencies,

01:05:40 they reached a dead end.

01:05:42 It was at this moment that Walker

01:05:44 unravelled a certain diagram.

01:05:46 The signal was repeated every 18 minutes.

01:05:48 It was huge.

01:05:50 But the moment he was preparing

01:05:52 to study it in more detail,

01:05:54 the signal disappeared after only 3 months,

01:05:56 leaving no trace.

01:05:58 Refusing to give up,

01:06:00 Walker and his team

01:06:02 once again scoured the sky,

01:06:04 hoping to find a clue.

01:06:06 Months passed, but nothing was discovered.

01:06:08 Walker was about to give up

01:06:10 when suddenly a new signal appeared.

01:06:12 It continued to repeat itself for 5 minutes.

01:06:14 Then it disappeared

01:06:16 before reappearing

01:06:18 exactly 22 minutes later.

01:06:20 The big question was to know

01:06:22 if this signal was linked to the previous

01:06:24 18-minute signal.

01:06:26 And, to discover it, Dr. Hurley Walker

01:06:28 dove back into the old radio data

01:06:30 of this area.

01:06:32 As they dug, they realized

01:06:34 that indeed, these signals were not new.

01:06:36 They had been sent to Earth

01:06:38 for 35 years.

01:06:40 Indian and American telescopes

01:06:42 had already spotted them in 1988,

01:06:44 but they had been drowned

01:06:46 by the influx of other data.

01:06:48 It was excellent news for astronomers,

01:06:50 because it meant

01:06:52 that they could now calculate the distance

01:06:54 that separated them from this mysterious object.

01:06:56 After doing the math,

01:06:58 they found that it was incredibly far away,

01:07:00 even on a cosmic scale.

01:07:02 It was 15,000 light-years away from Earth.

01:07:04 Now, the only thing

01:07:06 they had to discover was the precise nature

01:07:08 of this object.

01:07:10 Walker and his team began to compare it

01:07:12 to all known radio waves emitters.

01:07:14 Yet, its source remained a mystery.

01:07:16 The signals continued

01:07:18 to appear every 22 minutes

01:07:20 on NASA screens,

01:07:22 always concluding with the frustrating message

01:07:24 "no correspondence found".

01:07:26 Scientists have named it

01:07:28 JI 839-10.

01:07:30 Some believe

01:07:32 that this signal could come from an alien people.

01:07:34 Maybe this is the signal

01:07:38 that the SETI program of intelligence research

01:07:40 has been waiting for so long.

01:07:42 This project has been in operation for more than 50 years

01:07:44 and is trying to provide evidence

01:07:46 of the existence of a life beyond our planet.

01:07:48 It is also scouting the sky

01:07:50 in search of radio waves, laser pulses

01:07:52 and other mysterious signals.

01:07:54 So, maybe this is a way

01:07:56 for aliens to communicate their location to us.

01:07:58 Although all this may seem exciting,

01:08:00 we must keep

01:08:02 drawing conclusions.

01:08:04 To begin with,

01:08:06 we have no tangible evidence.

01:08:08 In the absence of concrete evidence,

01:08:10 all this is speculation.

01:08:12 And then, there are other more plausible explanations.

01:08:14 The most likely is that this signal

01:08:16 comes from a natural phenomenon.

01:08:18 And there are some theories on this subject.

01:08:20 The first theory

01:08:22 is that of the pulsar.

01:08:24 Imagine a huge star

01:08:26 in space,

01:08:28 much larger than our sun.

01:08:30 Sometimes, these big stars

01:08:32 end their lives during a spectacular event

01:08:34 called supernova.

01:08:36 When this happens,

01:08:38 the core of the star collapses on itself,

01:08:40 becoming incredibly compact,

01:08:42 as if you compress all the content of this star

01:08:44 in a tiny space.

01:08:46 This tiny and extremely dense core

01:08:48 is what is called a neutron star.

01:08:50 Some of these neutron stars

01:08:52 are very particular.

01:08:54 We call them pulsars.

01:08:56 They get their name from the fact

01:08:58 that they seem to pulsate energy,

01:09:00 like lights in space.

01:09:02 These pulsars have incredibly powerful

01:09:04 magnetic fields,

01:09:06 much more than what we would find on Earth.

01:09:08 They are like huge cosmic magnets.

01:09:10 And, because of this,

01:09:12 they project energy beams.

01:09:14 They also spin very fast,

01:09:16 so that these energy beams seem to blink

01:09:18 as they spin.

01:09:20 That said, the strange signal

01:09:22 that we detected seems to have

01:09:24 some similarities with pulsars.

01:09:26 But it's not quite that.

01:09:28 Pulsars generally have a predictable lifespan.

01:09:30 They slow down over time

01:09:32 and eventually interrupt their radio signals.

01:09:34 However,

01:09:36 our mysterious signal seems quite persistent

01:09:38 and blinks well beyond

01:09:40 the expected life expectancy of a pulsar.

01:09:42 Maybe it's just

01:09:44 not a typical pulsar,

01:09:46 or not a pulsar at all.

01:09:48 There is also the theory of the magnetar.

01:09:50 A magnetar is another type

01:09:52 of neutron star.

01:09:54 They are like overloaded versions of pulsars,

01:09:56 with even more powerful magnetic fields

01:09:58 and slightly longer pulsation periods.

01:10:00 Maybe this is the cause

01:10:02 of the persistence of our signal?

01:10:04 However, when we examined

01:10:06 these data, we realized that

01:10:08 the signal did not correspond

01:10:10 to the pulsations of a magnetar.

01:10:12 Magnetars do not only emit radio waves,

01:10:14 but also powerful X-rays

01:10:16 because they are very charged in energy.

01:10:18 But the signal we received

01:10:20 only contained radio waves.

01:10:22 We therefore deduced that it was

01:10:28 neither a pulsar nor a magnetar.

01:10:30 The signal behaves strangely

01:10:32 and suggests an unnatural source.

01:10:34 This means that there could be

01:10:36 something in the universe that scientists

01:10:38 have not yet fully grasped.

01:10:40 And there is finally a space body

01:10:42 about which we do not know much.

01:10:44 The last theory is that of the Nain pulsar.

01:10:46 A Nain pulsar is a star

01:10:48 that emits a regular flickering,

01:10:50 similar to a pulsar,

01:10:52 but which takes much more time

01:10:54 between each pulsation.

01:10:56 Usually, white dwarfs

01:10:58 are made up of remnants of small stars.

01:11:00 They do not flicker because

01:11:02 their magnetic field is not as powerful

01:11:04 as that of pulsars.

01:11:06 But when a white dwarf becomes quite heavy,

01:11:08 reaching almost the mass of our sun,

01:11:10 it becomes extremely dense

01:11:12 and begins to pulsate

01:11:14 with a strong magnetic field,

01:11:16 just like the latter.

01:11:18 They have an interesting particularity.

01:11:20 White dwarfs are made of electrons

01:11:22 and not of neutrons,

01:11:24 which is the case of pulsars.

01:11:26 When these charged electrons

01:11:28 begin to dance with the magnetic field,

01:11:30 they emit flashes of periodic light

01:11:32 that occur every 100 to 1000 seconds.

01:11:34 As you will remember,

01:11:36 our signal has a period of 22 minutes,

01:11:38 that is, 1320 seconds.

01:11:40 It is a little longer than ordinary white dwarf pulsars,

01:11:42 but it is what seems closest to the truth.

01:11:44 So far,

01:11:46 it seems to be the most plausible explanation.

01:11:48 But even this theory

01:11:50 is not yet fully confirmed.

01:11:52 It just shows how much of the universe

01:11:54 we still have to discover.

01:11:56 Like fast radio surges,

01:12:00 or FRBs, for example.

01:12:02 Another type of mysterious signal

01:12:04 that we have detected.

01:12:06 They are like fast and intense

01:12:08 energy emissions in the form of radio waves.

01:12:10 They receive a lot of energy.

01:12:12 FRBs are so powerful

01:12:14 that they can sometimes shine

01:12:16 brighter than entire galaxies.

01:12:18 Imagine this.

01:12:20 They emit as much in a few milliseconds

01:12:22 as our sun in three whole days.

01:12:24 These explosions occur everywhere in the sky

01:12:28 and at extremely high frequencies,

01:12:30 although some have already occurred

01:12:32 at lower frequencies.

01:12:34 Every day, we detect

01:12:36 about 10,000 FRBs in the sky.

01:12:38 Some of them repeat themselves,

01:12:40 but most of them occur only once

01:12:42 and disappear forever.

01:12:44 Alas, most of them

01:12:46 only last a fraction of a second,

01:12:48 and when their energy reaches us,

01:12:50 it is a thousand times weaker

01:12:52 than a mobile phone signal

01:12:54 from the moon.

01:12:56 That is why,

01:12:58 despite their brightness,

01:13:00 there are still many things

01:13:02 that we do not understand about them.

01:13:04 We are always trying to understand

01:13:06 what is going on in the universe.

01:13:08 We are always trying to understand

01:13:10 what is going on in the universe.

01:13:12 We are always trying to understand

01:13:14 what is going on in the universe.

01:13:16 We are always trying to understand

01:13:18 what is going on in the universe.

01:13:20 We are always trying to understand

01:13:22 what is going on in the universe.

01:13:24 We are always trying to understand

01:13:26 what is going on in the universe.

01:13:28 We are always trying to understand

01:13:30 what is going on in the universe.

01:13:32 We are always trying to understand

01:13:34 what is going on in the universe.

01:13:36 We are always trying to understand

01:13:38 what is going on in the universe.

01:13:40 We are always trying to understand

01:13:42 what is going on in the universe.

01:13:44 We are always trying to understand

01:13:46 what is going on in the universe.

01:13:48 We are always trying to understand

01:13:50 what is going on in the universe.

01:13:52 We are always trying to understand

01:13:54 what is going on in the universe.

01:13:56 We are always trying to understand

01:13:58 what is going on in the universe.

01:14:00 We are always trying to understand

01:14:02 what is going on in the universe.

01:14:04 Venus, with a complete rotation on its axis,

01:14:06 is as long as 243 days on Earth.

01:14:08 And what is even stranger,

01:14:10 despite the fact that Venus

01:14:12 knows one day without end,

01:14:14 is that its year is shorter than Earth's.

01:14:16 While Earth takes about 365 days

01:14:18 to make a complete orbit

01:14:20 around the Sun,

01:14:22 Venus does it in only 225 days.

01:14:24 So, in a way,

01:14:26 for Venus,

01:14:28 one day is more than a whole year.

01:14:30 Venus is a strange planet in general.

01:14:32 It is nicknamed

01:14:34 "the twin of Earth"

01:14:36 because of our similarities,

01:14:38 although it is a little smaller than our planet.

01:14:40 But there are also drastic differences.

01:14:42 For example,

01:14:44 it rotates in the opposite direction,

01:14:46 which means that the Sun rises

01:14:48 to the west and sets to the east.

01:14:50 And Venus is not the only one

01:14:52 to dance to its own rhythm.

01:14:54 Uranus does the same.

01:14:56 And finally, it's a bit of madness

01:14:58 on Venus in terms of atmosphere.

01:15:00 When you stand on Earth,

01:15:02 you don't really feel the weight of the air around you.

01:15:04 Well, on Venus,

01:15:06 this feeling would be comparable

01:15:08 to an elephant sitting on your shoulders.

01:15:10 Venus has an atmospheric pressure

01:15:12 90 times higher than Earth's.

01:15:14 The atmosphere there consists

01:15:16 of a thick layer of toxic gas.

01:15:18 For example, the carbon dioxide

01:15:20 released by all volcanoes.

01:15:22 It applies an incredible pressure.

01:15:24 This is translated by incredibly high temperatures.

01:15:26 So it is no wonder

01:15:28 that we still have to wait

01:15:30 before we can set foot on this planet one day.

01:15:32 Meanwhile, Mercury,

01:15:34 the closest planet to the Sun,

01:15:36 has an orbit even shorter than that of Venus.

01:15:38 It makes a full journey

01:15:40 around the Sun in only

01:15:42 about 88 Earth days.

01:15:44 However, it has a slow rotation on its axis,

01:15:46 which means that one day on Mercury

01:15:48 lasts about 176 Earth days.

01:15:50 Basically,

01:15:52 half a year for us.

01:15:54 Just like with Venus,

01:15:56 half a year for us.

01:15:58 As it is the closest planet to the Sun,

01:16:00 it is not surprising that Mercury

01:16:02 has extremely high temperature variations.

01:16:04 During the day,

01:16:06 these can exceed 420 °C,

01:16:08 enough to melt lead.

01:16:10 But wait for sunset.

01:16:12 At night, it goes down to a glacial -180 °C.

01:16:14 It is because Mercury

01:16:16 does not have a thick atmosphere like ours,

01:16:18 so the heat does not distribute

01:16:20 evenly across the planet.

01:16:22 If one side is plunged into darkness,

01:16:24 it will be extremely cold,

01:16:26 and the other side will be burning.

01:16:28 Just like if you left

01:16:30 an ordinary big rock under the sun

01:16:32 for a moment.

01:16:34 In fact, it is so cold that

01:16:36 there could even be ice on it.

01:16:38 Look at the region of the northern pole of the planet.

01:16:40 Especially these yellow spots,

01:16:42 lit by the sun inside the craters.

01:16:44 They indicate the presence of ice water.

01:16:46 And it turns out that the water is much more

01:16:48 common in space than we thought.

01:16:50 Mars is often nicknamed "the red planet".

01:16:52 It owes its nickname to the abundance

01:16:54 of iron oxide, or rust,

01:16:56 which covers its surface.

01:16:58 The rich iron minerals create this reddish

01:17:00 hue that colors the Martian landscape.

01:17:02 But it turns out that Mars is not just red.

01:17:04 If you stand on Mars,

01:17:06 you will see a land similar

01:17:08 to a desert of caramel colors,

01:17:10 bathing in a golden glow.

01:17:12 A little brown here and there,

01:17:14 and even slight greenish reflections.

01:17:16 Mars also has the largest mountain

01:17:18 in the entire solar system, Olympus-Mons.

01:17:20 At a height of about 22 km above sea level,

01:17:22 it is much higher than Mount Everest.

01:17:24 It was formed by the eruption

01:17:26 of a lava with low viscosity,

01:17:28 creating a structure similar

01:17:30 to a shield.

01:17:32 Since Mars is covered with sand,

01:17:34 it is also famous for its fantastic

01:17:36 dust storms.

01:17:38 But it turns out that they are even more

01:17:40 insane than we thought.

01:17:42 These storms can last months.

01:17:44 Although they may present challenges

01:17:46 for future human missions,

01:17:48 they also contribute to the unreal aspect

01:17:50 of the planet when it is observed from a distance.

01:17:52 And it is not only the storms to take into account,

01:17:54 but also the earthquakes of Mars.

01:17:56 Also known as seismic tremors,

01:17:58 they were detected for the first time

01:18:00 by NASA in 2019.

01:18:02 Unlike earthquakes,

01:18:04 which are often triggered

01:18:06 by tectonic plate movements,

01:18:08 we think that the tremors of Mars

01:18:10 result from the cooling

01:18:12 and contraction of the interior

01:18:14 of the planet.

01:18:16 It is interesting to see

01:18:18 how similar and yet so different

01:18:20 the two planets are.

01:18:22 Saturn's emblematic rings

01:18:24 could hold a secret

01:18:26 linked to the ancient past of the Earth.

01:18:28 These rings are mainly composed

01:18:30 of ice particles and debris

01:18:32 and are estimated to be relatively young

01:18:34 on a cosmic scale,

01:18:36 only a few hundred million years old.

01:18:38 Now, some theories claim

01:18:40 that they were born after a large-scale

01:18:42 disaster, the collision of two large moons

01:18:44 or the disintegration of a comet,

01:18:46 for example.

01:18:48 What is interesting is that this chronology

01:18:50 coincides with the age of the extinction

01:18:52 of dinosaurs on Earth.

01:18:54 Would there be a link? Who knows?

01:18:56 In fact, although Saturn wins the big prize

01:18:58 for its rings, it is not the only planet

01:19:00 in our solar system to have it.

01:19:02 Jupiter, Uranus and Neptune

01:19:04 also have their own sets of rings,

01:19:06 although they may not be

01:19:08 as visible and impressive

01:19:10 as those of Saturn.

01:19:12 However, there is something

01:19:14 by which Saturn really stands out.

01:19:16 The magnificent hexagon of its north pole.

01:19:18 It is a colossal figure

01:19:20 with six sides.

01:19:22 And each side of this incredible structure

01:19:24 measures about 14,500 km long,

01:19:26 or 1,900 km more

01:19:28 than the diameter of the Earth.

01:19:30 Scientists are not sure

01:19:32 how this hexagon

01:19:34 formed or why.

01:19:36 They think that this could be

01:19:38 due to variable wind speeds.

01:19:40 Or maybe it is shaped

01:19:42 by a localized jet stream,

01:19:44 slow and sinuous.

01:19:46 For the moment, it remains

01:19:48 another of Saturn's mysteries.

01:19:50 Like Saturn's hexagon, Jupiter

01:19:52 also has its own strange spot.

01:19:54 It is called the Great Red Spot.

01:19:56 It is a storm that has been raging

01:19:58 for at least 350 years and

01:20:00 is larger than the Earth itself.

01:20:02 Despite its name, the color of this spot

01:20:04 has varied over the years,

01:20:06 ranging from brick red to pale salmon pink.

01:20:08 Scientists continue to study

01:20:10 this tenacious storm,

01:20:12 unravelling the mysteries of its persistence

01:20:14 and its changing volutes.

01:20:16 On the meteorological level,

01:20:18 the Great Red Spot is a true epicenter.

01:20:20 It generates enormous pressure

01:20:22 in Jupiter's southern hemisphere.

01:20:24 During this time, Jupiter

01:20:26 itself is not left out

01:20:28 in terms of magnetic fields.

01:20:30 Its influence is colossal.

01:20:32 It extends far beyond the planet itself

01:20:34 and creates one of the most

01:20:36 vast and powerful auroras

01:20:38 of our solar system.

01:20:40 Because of this, Jupiter is a source

01:20:42 of intense radiation and fascinating

01:20:44 auroras. While the auroras of the Earth

01:20:46 are breathtaking,

01:20:48 Jupiter also has something

01:20:50 to offer. Its magnetic field

01:20:52 interacts with charged particles

01:20:54 from Jupiter's moons

01:20:56 and solar wind.

01:20:58 This creates visually striking auroras

01:21:00 at the level of its poles.

01:21:02 However, compared to the Earth,

01:21:04 the scale of these auroras is phenomenal.

01:21:06 Nothing compares to what we observe

01:21:08 on our planet.

01:21:10 But even this type of Great Red Spot

01:21:12 is not a unique feature

01:21:14 within our solar system.

01:21:16 The stormy giant,

01:21:18 Neptune, the eighth

01:21:20 and the farthest from the planets of the Sun,

01:21:22 also has its own Great Dark Spot.

01:21:24 Just like with Jupiter,

01:21:26 it is a huge vortex

01:21:28 in the middle of Neptune's atmosphere.

01:21:30 But unlike its Jupiterian counterpart,

01:21:32 this spot tends to appear

01:21:34 and disappear due to

01:21:36 the extremely changing

01:21:38 weather of Neptune.

01:21:40 Neptune, like Uranus,

01:21:42 is another frozen giant.

01:21:44 And like the other giants,

01:21:46 it has some of the most violent winds

01:21:48 of our solar system.

01:21:50 Its supersonic currents can reach

01:21:52 a speed of over

01:21:54 1,900 km/h.

01:21:56 And yes, it's not a joke.

01:21:58 But this explains its thick

01:22:00 cloud formation.

01:22:02 In fact, if you have ever dreamed of a planet

01:22:04 where diamonds rain,

01:22:06 you could be interested in this planet.

01:22:08 Deeply in the atmosphere of Neptune,

01:22:10 where the pressures are extreme,

01:22:12 scientists have hypothesized

01:22:14 that carbon atoms would be so compressed

01:22:16 that they would form diamonds.

01:22:18 These diamonds could then fall like a rain.

01:22:20 What a unique touch for a beautiful storm.

01:22:22 Neptune's moons have inherited

01:22:24 from their parents this strange weather.

01:22:26 For example, its largest moon,

01:22:28 Triton, has a touch of

01:22:30 cryovolcanism.

01:22:32 Instead of vomiting melting rocks

01:22:34 like terrestrial volcanoes,

01:22:36 Triton's cryovolcanoes

01:22:38 burst with a mixture of water, ammonia

01:22:40 and nitrogen. It looks like

01:22:42 ice geysers projecting their matter

01:22:44 into space. It looks like

01:22:46 in our only solar system,

01:22:48 each planet has its own fascinating

01:22:50 peculiarities. Let's hope we'll discover

01:22:52 other interesting things in the space

01:22:54 that is approaching the future.

01:22:56 [Music]

01:22:58 [Music]

01:23:00 [Music]

01:23:04 [Music]

01:23:10 [Music]

01:23:14 [Music]

01:23:18 [Music]

01:23:26 [Music]

01:23:28 [Music]

01:23:34 [Music]

01:23:40 [Music]

01:23:46 [Music]

01:23:52 [Music]

01:23:54 [Music]

01:24:00 [Music]

01:24:06 [Music]

01:24:12 [Music]

01:24:18 [Music]

01:24:20 [Music]

01:24:26 [Music]

01:24:32 [Music]

01:24:38 [Music]

01:24:44 [Music]

01:24:46 [Music]

01:24:56 [Music]

01:25:00 [Music]

01:25:06 [Music]

01:25:08 [Music]

01:25:14 [Music]

01:25:20 [Music]

01:25:26 [Music]

01:25:32 [Music]

01:25:34 [Music]

01:25:40 [Music]

01:25:46 [Music]

01:25:52 [Music]

01:25:58 [Music]

01:26:00 [Music]

01:26:06 [Music]

01:26:12 [Music]

01:26:18 [Music]

01:26:24 [Music]

01:26:26 [Music]

01:26:32 [Music]

01:26:38 [Music]

01:26:44 [Music]

01:26:50 [Music]

01:26:52 [Music]

01:27:02 [Music]

01:27:12 [Music]

01:27:14 [Music]

01:27:20 [Music]

01:27:26 [Music]

01:27:32 [Music]

01:27:38 [Music]

01:27:40 [Music]

01:27:50 [Music]

01:28:00 [Music]

01:28:02 [Music]

01:28:08 [Music]

01:28:14 [Music]

01:28:20 [Music]

01:28:26 [Music]

01:28:28 [Music]

01:28:34 [Music]

01:28:40 [Music]

01:28:46 [Music]

01:28:52 [Music]

01:28:54 [Music]

01:29:04 [Music]

01:29:14 [Music]

01:29:16 [Music]

01:29:26 [Music]

01:29:36 [Music]

01:29:38 [Music]

01:29:44 [Music]

01:29:50 [Music]

01:29:58 [Music]

01:30:00 [Music]

01:30:10 [Music]

01:30:20 [Music]

01:30:22 [Music]

01:30:32 [Music]

01:30:42 [Music]

01:30:44 [Music]

01:30:54 [Music]

01:31:04 [Music]

01:31:06 [Music]

01:31:16 [Music]

01:31:26 [Music]

01:31:28 [Music]

01:31:38 [Music]

01:31:48 [Music]

01:31:50 [Music]

01:31:52 [Music]

01:32:02 [Music]

01:32:12 [Music]

01:32:14 [Music]

01:32:24 [Music]

01:32:34 [Music]

01:32:36 [Music]

01:32:46 [Music]

01:32:56 [Music]

01:32:58 [Music]

01:33:08 [Music]

01:33:18 [Music]

01:33:20 [Music]

01:33:30 [Music]

01:33:40 [Music]

01:33:42 [Music]

01:33:52 [Music]

01:34:02 [Music]

01:34:04 [Music]

01:34:14 [Music]

01:34:24 [Music]

01:34:26 [Music]

01:34:36 [Music]

01:34:46 [Music]

01:34:48 [Music]

01:34:58 [Music]

01:35:08 [Music]

01:35:10 [Music]

01:35:20 [Music]

01:35:30 [Music]

01:35:32 [Music]

01:35:42 [Music]

01:35:52 [Music]

01:35:54 [Music]

01:36:04 [Music]

01:36:14 [Music]

01:36:16 [Music]

01:36:26 [Music]

01:36:36 [Music]

01:36:38 [Music]

01:36:48 [Music]

01:36:58 [Music]

01:37:00 [Music]

01:37:10 [Music]

01:37:20 [Music]

01:37:22 [Music]

01:37:32 [Music]

01:37:42 [Music]

01:37:44 [Music]

01:37:54 [Music]

01:38:04 [Music]

01:38:06 [Music]

01:38:12 [Music]

01:38:18 [Music]

01:38:24 [Music]

01:38:26 [Music]

01:38:36 [Music]

01:38:46 [Music]

01:38:48 [Music]

01:38:58 [Music]

01:39:08 [Music]

01:39:10 [Music]

01:39:20 [Music]

01:39:30 [Music]

01:39:32 [Music]

01:39:42 [Music]

01:39:52 [Music]

01:39:54 [Music]

01:40:04 [Music]

01:40:14 [Music]

01:40:16 [Music]

01:40:26 [Music]

01:40:36 [Music]

01:40:38 [Music]

01:40:48 [Music]

01:40:58 [Music]

01:41:00 [Music]

01:41:10 [Music]

01:41:20 [Music]

01:41:22 [Music]

01:41:32 [Music]

01:41:42 [Music]

01:41:44 [Music]

01:41:54 [Music]

01:42:04 [Music]

01:42:06 [Music]

01:42:16 [Music]

01:42:18 [Music]

01:42:28 [Music]

01:42:30 [Music]

01:42:40 [Music]

01:42:50 [Music]

01:42:52 [Music]

01:43:02 [Music]

01:43:12 [Music]

01:43:14 [Music]

01:43:24 [Music]

01:43:34 [Music]

01:43:36 [Music]

01:43:46 [Music]

01:43:56 [Music]

01:43:58 [Music]

01:44:08 [Music]

01:44:18 [Music]

01:44:20 [Music]

01:44:30 [Music]

01:44:40 [Music]

01:44:42 [Music]

01:44:52 [Music]

01:45:02 [Music]

01:45:04 [Music]

01:45:14 [Music]

01:45:24 [Music]

01:45:26 [Music]

01:45:36 [Music]

01:45:46 [Music]

01:45:48 [Music]

01:45:58 [Music]

01:46:00 [Music]

01:46:02 [Music]

01:46:12 [Music]

01:46:22 [Music]

01:46:24 [Music]

01:46:34 [Music]

01:46:44 [Music]

01:46:46 [Music]

01:46:56 [Music]

01:47:06 [Music]

01:47:08 [Music]

01:47:18 [Music]

01:47:28 [Music]

01:47:30 [Music]

01:47:40 [Music]

01:47:50 [Music]

01:47:52 [Music]

01:48:02 [Music]

01:48:12 [Music]

01:48:14 [Music]

01:48:24 [Music]

01:48:34 [Music]

01:48:36 [Music]

01:48:46 [Music]

01:48:56 [Music]

01:48:58 [Music]

01:49:14 [Music]

01:49:16 [Music]

01:49:18 [Music]

01:49:28 [Music]

01:49:38 [Music]

01:49:40 [Music]

01:49:50 [Music]

01:50:00 [Music]

01:50:02 [Music]

01:50:04 [Music]

01:50:14 [Music]

01:50:24 [Music]

01:50:26 [Music]

01:50:36 [Music]

01:50:46 [Music]

01:50:48 [Music]

01:50:58 [Music]

01:51:08 [Music]

01:51:10 [Music]

01:51:20 [Music]

01:51:30 [Music]

01:51:32 [Music]

01:51:42 [Music]

01:51:52 [Music]

01:51:54 [Music]

01:51:56 [Music]

01:51:58 [Music]

01:52:08 [Music]

01:52:18 [Music]

01:52:20 [Music]

01:52:30 [Music]

01:52:40 [Music]

01:52:42 [Music]

01:53:00 [Music]

01:53:02 [Music]

01:53:12 [Music]

01:53:22 [Music]

01:53:24 [Music]

01:53:34 [Music]

01:53:44 [Music]

01:53:46 [Music]

01:53:56 [Music]

01:54:06 [Music]

01:54:08 [Music]

01:54:18 [Music]

01:54:28 [Music]

01:54:30 [Music]

01:54:40 [Music]

01:54:50 [Music]

01:54:52 [Music]

01:55:02 [Music]

01:55:12 [Music]

01:55:14 [Music]

01:55:24 [Music]

01:55:34 [Music]

01:55:36 [Music]

01:55:46 [Music]

01:55:56 [Music]

01:55:58 [Music]

01:56:08 [Music]

01:56:18 [Music]

01:56:20 [Music]

01:56:30 [Music]

01:56:40 [Music]

01:56:42 [Music]

01:56:52 [Music]

01:57:02 [Music]

01:57:04 [Music]

01:57:14 [Music]

01:57:24 [Music]

01:57:26 [Music]

01:57:36 [Music]

01:57:46 [Music]

01:57:48 [Music]

01:57:58 [Music]

01:58:08 [Music]

01:58:10 [Music]

01:58:20 [Music]

01:58:30 [Music]

01:58:32 [Music]

01:58:42 [Music]

01:58:52 [Music]

01:58:54 [Music]

01:59:04 [Music]

01:59:14 [Music]

01:59:16 [Music]

01:59:26 [Music]

01:59:36 [Music]

01:59:38 [Music]

01:59:48 [Music]

01:59:58 [Music]

02:00:00 [Music]

02:00:10 [Music]

02:00:20 [Music]

02:00:22 [Music]

02:00:24 [Music]

02:00:34 [Music]

02:00:44 [Music]

02:00:46 [Music]

02:00:56 [Music]

02:01:06 [Music]

02:01:08 [Music]

02:01:18 [Music]

02:01:28 [Music]

02:01:30 [Music]

02:01:40 [Music]

02:01:50 [Music]

02:01:52 [Music]

02:01:54 [Music]

02:02:04 [Music]

02:02:14 [Music]

02:02:16 [Music]

02:02:26 [Music]

02:02:36 [Music]

02:02:38 [Music]

02:02:48 [Music]

02:02:58 [Music]

02:03:00 [Music]

02:03:10 [Music]

02:03:20 [Music]

02:03:22 [Music]

02:03:32 [Music]

02:03:42 [Music]

02:03:44 [Music]

02:03:54 [Music]

02:04:04 [Music]

02:04:06 [Music]

02:04:16 [Music]

02:04:26 [Music]

02:04:28 [Music]

02:04:38 [Music]

02:04:48 [Music]

02:04:50 [Music]

02:05:00 [Music]

02:05:10 [Music]

02:05:12 [Music]

02:05:22 [Music]

02:05:32 [Music]

02:05:34 [Music]

02:05:44 [Music]

Category

Transcript

Recommended