75 faits sur l'espace qui vous intrigueront et vous étonneront

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Transcript

00:00:00Attention, attention, something very exciting is happening on Saturn.

00:00:05This is what we call the season of rays.

00:00:07And no, the planet does not turn into a gigantic gas wheel.

00:00:11Let us enlighten you on this captivating phenomenon.

00:00:15Every year, NASA's Hubble Space Telescope

00:00:18devotes part of its time to observing Saturn.

00:00:21This gas giant is the second largest planet in the solar system.

00:00:25And this celestial body still has surprises in store for us.

00:00:28Let's take, for example, one of the most recent images of the planet Saturn.

00:00:32You see these blurry stripes.

00:00:34They indicate the beginning of the season of rays,

00:00:36better known as Spokes.

00:00:38Like our planet, Saturn is tilted on its axis,

00:00:42which gives it four distinct seasons.

00:00:44However, due to the colossal size of its orbit,

00:00:48each of these seasons lasts about seven terrestrial years.

00:00:51This is a crucial point to keep in mind.

00:00:53To grasp the unique concept of this Saturnian season,

00:00:56we must talk about the equinox.

00:00:58On Earth, it is the moment when the sun is exactly above the equator,

00:01:03making day and night of equal length.

00:01:05On Saturn, it is slightly different.

00:01:08An equinox occurs when Saturn's rings are tilted to one side in relation to the sun.

00:01:13Although equinoxes on Saturn take place every spring and every autumn,

00:01:17as on our planet,

00:01:19they occur much more rarely,

00:01:21about once every 15 terrestrial years.

00:01:24This is why astronomers are so enthusiastic about this event.

00:01:28Look now.

00:01:29There are two sharp rays on the B ring, on the left of the image.

00:01:33They look like the rays of a bicycle wheel.

00:01:36Their shade and shape vary.

00:01:38They can appear dark or light, depending on the angle and lighting.

00:01:43Sometimes, they look more like spots than ordinary radio rays.

00:01:48These spokes will not last long,

00:01:50but more and more will begin to appear as we approach May 6, 2025,

00:01:56the equinox date of autumn on Saturn.

00:01:58But what is the origin of these rays?

00:02:01Astronomers think that they could be caused by the magnetic field of the gas giant.

00:02:05When a planetary magnetic field interacts with the solar wind,

00:02:09it creates an electrically charged environment.

00:02:12On Earth, this phenomenon is manifested by boreal auroras.

00:02:15Regarding Saturn, the smallest particles of ice on its rings

00:02:19could also be charged electrically.

00:02:21It is likely that this will make them temporarily levitate

00:02:24above the larger blocks of ice that make up the rings.

00:02:28The spokes of Saturn's rings were first observed by NASA's Voyager mission

00:02:33in the early 1980s.

00:02:35At that time, we did not know that these rays were a seasonal phenomenon.

00:02:40Voyager 2 simply flew over the planet, then continued its journey.

00:02:44To understand the nature and operation of these rays,

00:02:47astronomers needed a space telescope capable of observing Saturn from a distance.

00:02:52A telescope like Hubble.

00:02:54The most recent equinox on Saturn took place in 2009

00:02:58when NASA's Cassini space probe was in orbit around the gas giant.

00:03:03Cassini sent many astonishing clichés to Earth,

00:03:07quickly demonstrating that these rays were not caused by gravitational interactions with Saturn,

00:03:12nor by the influence of its moons, or small satellites that make up the rings.

00:03:16In 2005, Cassini confirmed that the rays were linked to Saturn's magnetic field.

00:03:22The Cassini mission ended in 2017,

00:03:25but Hubble is now pursuing long-term surveillance of changes around Saturn.

00:03:29Despite all these observations,

00:03:31astronomers still cannot predict the start and duration of the spokes' season.

00:03:36Fortunately, Saturn's pro-eminent rings offer an ideal laboratory to study this phenomenon.

00:03:43Although the other gas giants in the solar system also have rings,

00:03:47these are not as visible,

00:03:49and scientists do not know if spokes appear there.

00:03:52However, rays are not the only fascinating space phenomenon.

00:03:56Our solar system is full of wonders.

00:03:59Imagine standing at the Martian equator, foot above.

00:04:02Your feet would feel a pleasant temperature,

00:04:05comparable to a warm spring day.

00:04:07However, you would have to wear a hat,

00:04:10because at the height of your head, there would be a glacial cold.

00:04:13Venus rotates in the opposite direction of most other planets in the solar system and the sun itself.

00:04:19An advanced hypothesis by astronomers is that a past collision with a massive object,

00:04:24such as an asteroid, could be the cause.

00:04:27Jupiter's moon, Io, is the most volcanically active body in the solar system,

00:04:32with several hundred volcanoes.

00:04:35Its surface has a strange yellowish hue,

00:04:38which gives it the appearance of a pepperoni pizza.

00:04:41Europe, one of Jupiter's four largest satellites,

00:04:45is covered with ice, with an estimated thickness of between 16 and 24 km.

00:04:50Some areas of this icy surface are smooth,

00:04:53which would make this place an ideal terrain for artistic skating.

00:04:57And if we gathered all the asteroids known to the solar system,

00:05:01their total mass would be less than 10% of that of our moon.

00:05:05Scientists think that Mercury could still have a partially melted core,

00:05:10which would explain the presence of a magnetic field,

00:05:13although it represents only 1% of the power of Earth's.

00:05:17Mercury's core is about 42% of the total volume of the planet.

00:05:22In addition, its surface has ridges, called lobed escarpments,

00:05:26which formed when its iron core caused a contraction of the crust by cooling.

00:05:32These escarpments can extend for hundreds of kilometers,

00:05:35and reach more than 1,000 meters in height.

00:05:38Uranus is the only planet in the solar system to rotate on the side.

00:05:42This feature could be due to an old cataclysmic collision with an object the size of Earth,

00:05:47although this is only a theory for now.

00:05:50Mars could acquire a set of rings in the next 70 million years.

00:05:55Its largest moon, Phobos, is gradually approaching the planet.

00:06:00One day, it could be disintegrated by the gravitational forces of Mars,

00:06:04and turn into a ring that could persist for millions of years.

00:06:08We won't be there to see that, so let's believe them.

00:06:12Scientists estimate that the surface of the moon has more craters than that of Earth,

00:06:18due to the absence of natural activity on our satellite.

00:06:21On Earth, winds, rains, earthquakes, and erosion

00:06:26continuously change the surface.

00:06:29However, the moon has almost no meteorological conditions to alter its appearance.

00:06:34Saturn is the most flattened planet in the solar system.

00:06:38It is compressed at the poles,

00:06:40with an equator located about 6,400 kilometers further from the center of the planet than the poles.

00:06:45The Hubble Space Telescope, which weighs almost as much as two African elephants,

00:06:50and is as long as a big school bus,

00:06:52has made nearly 1.5 million observations since its launch in 1990.

00:07:00This data has allowed astronomers to write about 15,000 scientific articles.

00:07:06Everything on Earth, and everything that people can observe in space with a telescope,

00:07:11is considered normal matter, made up of atoms and molecules,

00:07:16and represents only less than 5% of the universe.

00:07:19Nearly 68% is made up of dark energy,

00:07:22and the remaining 27% is dark matter.

00:07:26Is it really important?

00:07:28Yes, absolutely.

00:07:29Saturn has a mysterious vortex that swirls above its south pole.

00:07:34This phenomenon resembles a huge hurricane-type storm,

00:07:38measuring nearly 8,000 kilometers in diameter,

00:07:41which is two-thirds the diameter of the Earth.

00:07:44What intrigues astronomers is that although this vortex looks like a hurricane,

00:07:48it does not behave like one.

00:07:51Saturn is also the only planet in the solar system that is less dense than water.

00:07:55In other words, if you found a bathtub big enough to contain this gas giant,

00:08:00it would float like a duck in rubber.

00:08:03Moon quakes do not occur as frequently as earthquakes.

00:08:08But when they do, they occur closer to the center of the satellite.

00:08:13Scientists think these moon quakes could be caused by the gravity of the Earth and the Sun.

00:08:19One of Saturn's moons, Jupiter, has a strange bicolor pattern.

00:08:24The two hemispheres of the moon are very different.

00:08:27One is light, while the other is surprisingly dark.

00:08:30Scientists have not yet elucidated this mystery.

00:08:33The only asteroid belt known to astronomers in the solar system is between Mars and Jupiter.

00:08:39Thousands of asteroids occupy this area.

00:08:42They are solid objects of irregular shape and varied sizes, each much smaller than a planet.

00:08:48Scientists have analyzed the chemical composition of some meteorites found in the Sahara Desert,

00:08:53in Antarctica and elsewhere.

00:08:56It turns out that some of these rocks have a Martian origin,

00:08:59while others come from the moon or the asteroid belt between Mars and Jupiter.

00:09:05Ah, will space rocks never cease to fascinate us?

00:09:10You've been training for years.

00:09:14You know you're ready.

00:09:17You stand on the doorstep.

00:09:19You take a deep breath and bravely open it.

00:09:23You jump outside the International Space Station and into the vastness of space.

00:09:28Ah, it's always so exciting, you say in your transmitter.

00:09:35You feel as light as a feather in space.

00:09:38Except for the suit, of course.

00:09:41It's true what this guy told you one day.

00:09:43Astronaut suits limit body movements by at least 20%.

00:09:48For you, that means you have a 20% chance of getting sick in space.

00:09:53Which is not a good thing.

00:09:55We are not allowed to make mistakes when we do this job.

00:09:58You finally arrive at the docking station.

00:10:01You look around you and you see the place of the station that needs to be repaired.

00:10:05This is where the other shuttles get bored when they arrive close to Earth or other planets.

00:10:10A week ago, a shuttle from Jupiter miscalculated its arrival and broke part of the post.

00:10:16You tied the piece to replace your belt.

00:10:19Now all you have to do is screw it.

00:10:22You spent hours training underwater.

00:10:25You wore a heavy, warm and uncomfortable suit in a pool

00:10:29in order to know the exact movements you have to do here.

00:10:32Be careful!

00:10:34Screams Sarah on the transmitter.

00:10:36You don't even have time to ask what it is.

00:10:38A storm of debris takes you by surprise at an absurd speed.

00:10:42It shakes everything around you.

00:10:44You try to hang on to your security cable.

00:10:46But...

00:10:47Oh no!

00:10:48A debris comes from outside and is the visor of your helmet.

00:10:50Bob, are you okay?

00:10:52Asks Sarah via the transmitter.

00:10:54The impact shook you a little.

00:10:56But everything seems normal.

00:10:58The meteorites have finally disappeared.

00:11:00So you can focus on your task.

00:11:02You pull the cable to which the piece to be replaced is attached to you.

00:11:05But...

00:11:06There is nothing at the other end.

00:11:08No, nothing at all.

00:11:10Oh no!

00:11:11You say to yourself.

00:11:12Um...

00:11:13Sarah, we lost a piece.

00:11:15I repeat.

00:11:16We lost a piece.

00:11:18The situation is quite serious and you are aware of it.

00:11:21Everything that falls into space can collide with the International Space Station or other vehicles.

00:11:27You try to remember your training but your head is empty.

00:11:31It's worse than the time when you broke your girlfriend's favorite ceramic pot.

00:11:36Sarah, the astronaut who accompanies you on board the station, shouts on the transmitter.

00:11:41Oh no Bob!

00:11:42Tell me it's not true!

00:11:44It's a disaster!

00:11:45I'm coming!

00:11:47You spot the piece in question under the ISS.

00:11:50It is the size of a medium-sized car door and moves quite quickly.

00:11:55Here's what can happen.

00:11:56The piece can go back down to Earth and enter the atmosphere.

00:11:59It will then probably catch fire and disintegrate on the way.

00:12:03But even if this is the case, the image of NASA will suffer and you will be reprimanded.

00:12:08It is also possible that the lost piece takes a little momentum, gets into orbit and hits the ISS.

00:12:14And you too on the same occasion.

00:12:16Or a satellite that would be on the same orbit.

00:12:19So here it is.

00:12:20If you thought space was an infinite void, you were wrong.

00:12:25Since different countries have begun to build sufficiently solid equipment to travel in space,

00:12:30the place is very crowded.

00:12:32There are few people there, but there are satellites, asteroids and space debris.

00:12:38You were surprised to learn one day that the Earth receives daily meteor shower.

00:12:43But they are so small that no one on the surface of the planet notices them.

00:12:48They usually turn to ash before reaching the ground.

00:12:52But that's not all.

00:12:53What just happened to you on this mission has already happened on several other missions.

00:12:58Astronauts are constantly losing objects in space.

00:13:01So much so that NASA had to create a division charged with tracking

00:13:05and monitoring the orbit of all these debris floating around the planet.

00:13:09You would not come back if you were told that there are more than 23,000 debris

00:13:13the size of a bullet in orbit in space.

00:13:16And half a million smaller objects.

00:13:19As you are about to detach your cable and venture dangerously into space without any protection,

00:13:24you notice that Sarah is in front of you.

00:13:27You can not let her do that alone.

00:13:29So you decide to accompany her.

00:13:31You know it goes against all NASA manuals and all the training you have followed.

00:13:36But you say to yourself, if it works in the movies, it must work for us.

00:13:40But you know perfectly well that it makes no sense.

00:13:43Sarah is close to the piece of debris.

00:13:45But the weight of her body makes her orbit in a completely different direction.

00:13:49OK, you say to yourself, it's your turn to shine and be a hero.

00:13:53You try to move your arms as you would underwater, but there is no friction in space.

00:13:58You can not swim to get this piece of equipment.

00:14:02You try to contact Sarah, but she does not answer anymore.

00:14:05So you'll have to do it alone now.

00:14:10For one reason or another, you start spinning on the same orbit as the lost piece.

00:14:16It is probably because of the amount of things you have attached to you.

00:14:20Or maybe it's the burrito you ate this morning.

00:14:23Do you feel like George Clooney in the movie Gravity?

00:14:26No, even better.

00:14:28You feel like Obi-Wan Kenobi.

00:14:30Yes, you feel as strong and powerful as a Jedi right now.

00:14:34You keep your hands tense in front of you, hoping that the collision with the debris will be smooth.

00:14:40And 3, 2, 1, successful landing.

00:14:43I'm kidding, but yes, you managed to get to the debris.

00:14:47Hooray!

00:14:48And now, you say to yourself.

00:14:51I guess you should have seen your plan a little more in depth, huh?

00:14:55You do not have the possibility to guide the debris.

00:14:58And you can no longer contact the mission control center to tell them that the object,

00:15:02and yourself, are on your way to somewhere.

00:15:06Do not be afraid.

00:15:07You did not go all this way to start being afraid.

00:15:10What are your options?

00:15:12First, mentally photograph your planet.

00:15:15From up there, it never disappoints.

00:15:17Then, ask yourself what are the different scenarios possible in such a situation.

00:15:23Your normal weight cannot be enough to extract you from Earth's orbit.

00:15:28In the hypothetical scenario where this would happen,

00:15:30you would probably be sucked into the orbit of Venus,

00:15:33and you would have a bad time.

00:15:35It is extremely hot there.

00:15:37Even if in mythology, Venus represents love,

00:15:40there is nothing pleasant in the neighborhood of this planet.

00:15:43And you know it.

00:15:44If you got too close, your space suit would not stand the heat.

00:15:48It can only withstand a maximum temperature of 120 ° C.

00:15:53And the atmosphere of Venus can reach 370 ° C.

00:15:58But honestly, the worst scenario is much simpler than that.

00:16:01Your space suit could decide to drown your ears, your nose and your mouth in water.

00:16:06Yes, this has already happened when leaving space.

00:16:09You see, for your space suit to stay fresh,

00:16:12it relies on the 3.8 liters of water of its cooling system.

00:16:16This system, which is supposed to eject air recycled from the back of your helmet,

00:16:20can start to flee.

00:16:22And as you are stuck in the middle of nowhere,

00:16:24you have no place, you, where to flee.

00:16:28But wait, what is profiling on the horizon?

00:16:31A modular space shuttle.

00:16:33You try to scream, but no one hears you out of your helmet.

00:16:37You make signs with your arms.

00:16:39Here, it is heading straight for you.

00:16:42Finally, Sarah says, I took a long time to find you.

00:16:45Apparently, she came back to the station just in time to catch you

00:16:49before you go wandering in infinite space.

00:16:53I guess I'm going to lose some astronauts points because of this little misadventure, huh?

00:16:58Do you say?

00:16:59Yes, that's for sure.

00:17:05Recently, Chinese scientists have discovered something interesting on the moon.

00:17:09An unusual crystal.

00:17:11They also discovered that this crystal contains an element

00:17:14that can literally replace nuclear fuel.

00:17:17So let's dig into the subject.

00:17:20The composition of the moon has long remained a mystery to us.

00:17:24Half a century has passed since the Apollo 11 mission.

00:17:27Unfortunately, we have not traveled a lot on the moon since.

00:17:31It is therefore not surprising that it is not so easy for us to study it.

00:17:35But recently, a breakthrough has been made in this area.

00:17:38In December 2020, Chinese scientists sent the Chang'e-5 probe to the moon.

00:17:44The mission was named after the ancient Chinese goddess of the moon, Chang'e.

00:17:48Rather poetic, isn't it?

00:17:50Anyway, the probe went to the closest face to the moon.

00:17:53It spent several days digging the surface and the rocks,

00:17:56then it came back to Earth.

00:17:58In total, it collected about 2 kg of various lunar rocks,

00:18:02including basalt, solidified lava and others.

00:18:07This may not seem very impressive, but it's actually a mini drill.

00:18:12After all, we have not collected lunar samples since 1976.

00:18:17However, these samples are very important to learn the history of our world.

00:18:22We fought for years to discover, for example, how the moon was born.

00:18:28There were many theories, but we still could not find solid evidence for any of them.

00:18:34But thanks to the last missions and certain computer simulations,

00:18:38scientists have finally discovered the truth.

00:18:41The moon was born when any planet crumbled on our Earth several million years ago.

00:18:47This dwarf planet was slightly smaller than Mars.

00:18:50Fragments of the Earth went into space, but some remained in our orbit.

00:18:55Then they stuck together and formed the moon.

00:18:59It seems scary, but in reality, the birth of the moon is the best thing that has ever happened to our planet.

00:19:05Without this magnificent satellite, all our oceans would still be small puddles of water.

00:19:10Life would not have appeared on Earth at all.

00:19:13So it's already an incredible discovery in itself.

00:19:16But that's not all.

00:19:18By studying the collected rocks, scientists at the Beijing Research Institute

00:19:22discovered something unusual.

00:19:24A rare lunar crystal.

00:19:27It looks pretty common, doesn't it?

00:19:29Just a tiny monocrystal and transparent the thickness of a human hair.

00:19:33We had made such discoveries on the moon before.

00:19:36These crystals formed as a result of a volcanic activity,

00:19:39just like some pomegranates on Earth.

00:19:42Because the place where they discovered these crystals also experienced volcanic eruptions.

00:19:461.2 billion years ago.

00:19:49This means that this little crystal is over a billion years old.

00:19:55But that's not the most important thing.

00:19:57What really matters is that this crystal is made of a unique material,

00:20:01that we had never seen before.

00:20:03Researchers from the International Mineralogical Association

00:20:06have confirmed that such a composition can't be found anywhere on Earth.

00:20:11The crystal was named Chang'e Zit Y,

00:20:14again according to the same Chinese divinity of the moon.

00:20:18And that's another achievement.

00:20:20It's the sixth previously unknown mineral that we found on the moon,

00:20:24and the very first found by China.

00:20:26It has now become the third country in the world to make such a lunar discovery.

00:20:31However, this tiny crystal is not the only remarkable thing they found.

00:20:36After studying this gem and about 140,000 other lunar particles,

00:20:40scientists discovered something else.

00:20:44They found helium-3.

00:20:47Why is this important?

00:20:49Because it's one of the elements that feeds the sun and the other stars in our universe.

00:20:57We tend to say things like,

00:20:59turn off the sun, the sun burns, and so on.

00:21:02And that's one of the reasons why many people

00:21:04really think that the sun is a huge ball of fire.

00:21:08But that's not the case.

00:21:10Its combustion is actually a completely different process,

00:21:13called nuclear fusion.

00:21:16The process itself is quite simple.

00:21:19During this reaction, the hydrogen of the star turns into helium.

00:21:23But this simple process is actually one of the most violent

00:21:26and powerful reactions in the universe.

00:21:29There is a real pool of particles inside the sun.

00:21:33The hydrogen nuclei, which agitate in all directions,

00:21:36constantly repel each other, because they are all positively charged.

00:21:41And they could continue to do so without disturbing anyone.

00:21:45If there were no stars.

00:21:47The stars are a bit sparse.

00:21:50Their gravity is so strong that they catch billions of these small atoms

00:21:54and squeeze them against each other.

00:21:57By combining with each other, these atoms create new heavy elements,

00:22:01like the mentioned helium.

00:22:03And when this happens, they project a lot of energy into space.

00:22:08That's how the sun burns.

00:22:10At the same time, it spreads an amount of energy that we can't even imagine.

00:22:15But what is helium-3?

00:22:18Well, it's an element that could make shadow even in the sun.

00:22:23The fusion of helium-3 atoms releases even more energy

00:22:27than in a typical nuclear fusion.

00:22:30And above all, it does not pollute the atmosphere with harmful elements,

00:22:33such as radiation.

00:22:36We have very, very little helium-3 on Earth.

00:22:40Its prevalence in our atmosphere is about 1 in 1 million.

00:22:43And in addition, it constantly tries to escape to return to space.

00:22:48However, scientists have recently discovered

00:22:51that there is a place that contains a lot of this element.

00:22:55Yes, you guessed it, it's the Moon.

00:22:58It is thought that there is more helium-3 on the Moon than on Earth

00:23:01because of the solar winds.

00:23:03The sun has been bombarding the moon with helium-3 for billions of years.

00:23:08So much so that today, there is helium-3 everywhere.

00:23:11It is not so impressive if we compare it to Jupiter.

00:23:14But do not forget the amount of energy it can release.

00:23:18You should know that with only 25 tons of helium-3,

00:23:21it would be possible to provide energy to the United States for a whole year.

00:23:26However, there are about 350,000 tons on Earth

00:23:29and more than 1 million tons on the Moon.

00:23:33These only sources could meet the needs of all of the United States

00:23:36for thousands of years.

00:23:38So, there is a lot of helium-3 on the Moon.

00:23:41So, in the future, helium-3 could become a new source of fuel.

00:23:46And it surpasses nuclear fuel in almost all areas.

00:23:50Helium-3 does not leave waste or harmful radiation.

00:23:53It is more powerful and not so dangerous.

00:23:56In other words, this ecological and efficient energy

00:23:59could be a revolution for our planet.

00:24:06But then, what are we waiting for?

00:24:08There is a small hiccup.

00:24:10Unfortunately, we have not yet found anything as powerful and hot as the stars.

00:24:15However, to use helium-3,

00:24:18we need temperature and magnet pressure.

00:24:21We need a thermonuclear reactor.

00:24:24And we have no idea how to build it for the moment.

00:24:27And even if we could heat it at such temperatures

00:24:30and get the necessary pressure,

00:24:32we still do not really know how to manipulate helium-3

00:24:35correctly.

00:24:37Therefore, even if we have an infinite amount of helium-3,

00:24:40we will still not be able to use it.

00:24:43But there is a potential element behind helium-3.

00:24:46Several countries have already started a race for lunar resources.

00:24:51And now that Chang'e-5 has discovered a new helium-3 deposit

00:24:55on the closest face to the Moon,

00:24:58this race could become global.

00:25:01For example, China is already planning a new lunar mission in 2024,

00:25:05Chang'e-6.

00:25:07During this mission,

00:25:09the Chinese want to collect the first samples of the hidden face of the Moon.

00:25:13As you can see,

00:25:15finding this lunar crystal was very important to us.

00:25:18These crystals can help us find new ways to create helium-3.

00:25:22And if we succeed,

00:25:24humanity will enter a new era.

00:25:27But to achieve this,

00:25:29we still have to solve a number of problems.

00:25:33How to deliver a bunch of these lunar crystals to Earth?

00:25:36How to make them produce energy?

00:25:38And so on.

00:25:40Let's hope that in the future, these problems will be solved

00:25:43and that we will find a way to produce clean, safe and unlimited energy.

00:25:50The Earth is not flat, but Jupiter could have been.

00:25:53Instead of large round spheres,

00:25:55the gas giants of our solar system

00:25:57may have started their lives as simple crepes.

00:26:00Jupiter was one of our oldest neighbors.

00:26:02It is 4.6 billion years old, just like our Sun.

00:26:06And when it was still young,

00:26:08it probably formed in a protoplanetary disk.

00:26:12Everything starts with stars.

00:26:14When a star is still forming,

00:26:16it does not look like a round object.

00:26:18It's more like a large disk of matter.

00:26:21At this stage, hot winds blow,

00:26:23composed of charged particles.

00:26:25The dust of this disk contains elements like carbon and iron.

00:26:29Some of them collide and remain together,

00:26:33forming larger objects.

00:26:35The dust turns into pebbles,

00:26:37the pebbles turn into rocks,

00:26:39and the rocks hit each other,

00:26:41becoming larger and larger.

00:26:43The gas present in the disk helps all these solid pieces to agglutinate.

00:26:47Some detach, but others remain together.

00:26:50And they become the basis of the planets.

00:26:53They are called planetesimals.

00:26:55Even gas giants like Jupiter

00:26:57began as tiny particles of dust,

00:27:00smaller than a human hair.

00:27:03Finally, they formed their own disk of matter.

00:27:06Then, they began to revolve around our Sun,

00:27:10growing as they accumulated gas and rocks,

00:27:13like a big snowball.

00:27:16The gas giants are special.

00:27:18They are born from the coldest parts of the disk.

00:27:21In these cold regions,

00:27:23the molecules are slower,

00:27:25making them easier to capture.

00:27:27The water can freeze,

00:27:29and tiny pieces of ice stick together

00:27:32and mix with dust.

00:27:34These snowballs then gather

00:27:36and form the cores of vast planets

00:27:38like Jupiter, Saturn, Uranus and Neptune.

00:27:42In the warmer regions,

00:27:44near the star,

00:27:46telluric planets like Mercury,

00:27:48Venus, Earth and Mars

00:27:50begin to form.

00:27:52After the birth of the ice giants,

00:27:54there was not much gas left

00:27:56for these tiny celestial bodies,

00:27:58and it could take tens of millions of years

00:28:00for such planets to form

00:28:02after the birth of a star.

00:28:04Our Sun was growing at the same time,

00:28:06sucking in the gas close

00:28:08and pushing the distant objects even further.

00:28:10After billions of years,

00:28:12the disk has completely changed,

00:28:14turning into a spherical star

00:28:16with a lot of giant and tiny planets,

00:28:18asteroids, moons,

00:28:20meteoroids

00:28:22and comets around it.

00:28:27Recently, simulations have shown

00:28:29that these proto-planets,

00:28:31as we call these first dust conglomerates,

00:28:33did not start by looking like the planets

00:28:35we know.

00:28:37In the case of gas giants like Jupiter,

00:28:39they would look more like crushed balls

00:28:41or M&M's.

00:28:43When the Sun was still young,

00:28:45the gas and dust disk

00:28:47surrounding it cooled down

00:28:49and became unstable.

00:28:51It began to break into large pieces.

00:28:53These gathered

00:28:55under the effect of an implacable gravity

00:28:57to create Jupiter.

00:28:59Then it became a spherical gas giant

00:29:01over time.

00:29:03Quantities of anomalies can occur

00:29:05during this process of planet formation.

00:29:07Have you ever wondered

00:29:09why Venus or Uranus

00:29:11rotate in the opposite direction?

00:29:13Usually, when things are formed

00:29:15from a rotating gas disk,

00:29:17they tend to rotate in the same direction.

00:29:19If you rotate a bunch of balls

00:29:21tied to a string, for example,

00:29:23they will all rotate in the same way.

00:29:25So, theoretically,

00:29:27all planets should also

00:29:29rotate in the same direction.

00:29:31But there are also many objects

00:29:33that move quickly in our solar system,

00:29:35such as comets and asteroids.

00:29:37When they collide with planets,

00:29:39especially during their first days,

00:29:41this impact can lead them

00:29:43to rotate in the opposite direction.

00:29:45Venus and Uranus probably survived

00:29:47a large-scale collision.

00:29:49Fortunately, they were not ejected

00:29:51into the distant space.

00:29:53The gravity of the Sun

00:29:55and neighboring planets

00:29:57kept them in their place.

00:29:59There are also

00:30:01what are called

00:30:03gravitational waves.

00:30:05These are celestial bodies

00:30:07that rotate so that one side

00:30:09is always facing their star,

00:30:11while the other remains

00:30:13in perpetual darkness.

00:30:15Thus, one side is always very hot,

00:30:17while the other is extremely cold.

00:30:19If we lived on such a planet,

00:30:21we could only exist on a thin band

00:30:23between these two extremes.

00:30:25These planets are formed

00:30:27when they are very close to their star.

00:30:29The gravitational forces at work

00:30:31slow down the rotation

00:30:33of the planet until it corresponds

00:30:35to the time it takes to orbit

00:30:37around its star.

00:30:39Imagine that you are turning on your chair.

00:30:41Someone approaches you and,

00:30:43holding your chair in his hands,

00:30:45starts to turn with you.

00:30:47In this way, you will face each other

00:30:49all the time.

00:30:51The planets in synchronous rotation

00:30:53work a little like this.

00:30:55Our Moon is also in synchronous rotation

00:30:57with the Earth.

00:31:00We have discovered

00:31:02more than 5,000 exoplanets

00:31:04outside our solar system.

00:31:06Some of them have very strange orbits.

00:31:08There are some, for example,

00:31:10that have incredibly long orbits,

00:31:12thousands of years

00:31:14to make a single revolution

00:31:16around their star,

00:31:18or very unequal orbits,

00:31:20similar to those of comets,

00:31:22or those planets called Jupiter Hot,

00:31:24which are very close to their star,

00:31:26much closer than Mercury

00:31:28But these planets could not have formed

00:31:30where they are now.

00:31:32As their solar system evolved,

00:31:34they, for one reason or another,

00:31:36changed position.

00:31:38This rearrangement is called

00:31:40planetary migration.

00:31:44There are three ways

00:31:46this migration can occur.

00:31:48First, due to the gas and dust

00:31:50in rotation around the planet.

00:31:52When a planet collides

00:31:54with this matter,

00:31:56it can create spiral patterns in the gas.

00:31:58These patterns can either bring the planet

00:32:00closer to the center,

00:32:02or move it away, depending on

00:32:04how they mix.

00:32:06This is called a type I migration.

00:32:08This is what Jupiter experienced

00:32:10when it moved closer to the sun

00:32:12billions of years ago.

00:32:14This also explains the existence

00:32:16of Jupiter Hot.

00:32:18Second, large planets can move

00:32:20smaller ones, changing their trajectory.

00:32:22Third, the gravity of the star

00:32:24can attract the planet,

00:32:26making its orbit circular.

00:32:30Have you ever heard

00:32:32about wandering planets?

00:32:34Imagine a lonely planet,

00:32:36floating in the vastness of space

00:32:38without being attached to any star.

00:32:40These are the wandering nomads

00:32:42of our galaxy, condemned

00:32:44to wander eternally.

00:32:46And there are so many!

00:32:48There could be more planets in liberty

00:32:50than planets linked to a star.

00:32:52We are talking here about thousands

00:32:54of billions of wandering bodies

00:32:56in our Milky Way.

00:32:58It is not uncommon for them to be as massive

00:33:00as our biggest planet, Jupiter.

00:33:02But most of them would be

00:33:04a size more comparable to that of the Earth.

00:33:06There are even some

00:33:08that could have a thick atmosphere

00:33:10capable of keeping them warm.

00:33:12Although they are far from all stars,

00:33:14some of these planets could have

00:33:16horrors to cut the breath,

00:33:18while others could be

00:33:20unhavre potentiel pour la vie.

00:33:22There is even a chance

00:33:24that they could inhabit an extraterrestrial life.

00:33:26These planets could bump into other stars,

00:33:28or even entire planetary systems

00:33:30during their crazy races through space.

00:33:32Sometimes, they can be captured

00:33:34by the gravity of a star

00:33:36for a certain time,

00:33:38before being ejected back into space.

00:33:40But how are they born?

00:33:42Sometimes, during this chaotic formation process,

00:33:44all the planets

00:33:46do not manage to stay close

00:33:48to each other.

00:33:50Some of them are expelled

00:33:52from their solar system

00:33:54due to the gravitational attraction

00:33:56of other planets,

00:33:58or passing stars.

00:34:00These ejected planets

00:34:02then become wandering planets.

00:34:04In 2012, astronomers

00:34:06discovered a solar system

00:34:08dating from the beginning of the universe.

00:34:10This system includes a star

00:34:12and two planets.

00:34:14It was nicknamed the Fossil System.

00:34:16This star is incredibly old,

00:34:18about 13 billion years old.

00:34:20It is almost as old

00:34:22as our universe itself.

00:34:24This system is mainly composed

00:34:26of hydrogen and helium.

00:34:28This is unusual,

00:34:30because planets are generally formed

00:34:32from gas clouds containing heavier elements.

00:34:34This is when we realized

00:34:36that the way planets were formed

00:34:38before was different

00:34:40from the way they are formed today.

00:34:42We know that the stars

00:34:44and metals are the most likely

00:34:46to have planets.

00:34:48In astronomical terms,

00:34:50metal means any chemical element

00:34:52other than hydrogen and helium.

00:34:54But in the primitive universe,

00:34:56there were not many heavy elements.

00:34:58Most of them were created

00:35:00inside the stars,

00:35:02and then dispersed in space

00:35:04when they exploded.

00:35:06So, when did the very first planets

00:35:08form?

00:35:10This newly discovered system

00:35:12These two giant planets

00:35:14are orbiting around a star

00:35:16which is incredibly poor in metals

00:35:18and extremely old.

00:35:20This should be very rare,

00:35:22even impossible,

00:35:24but they exist, yet.

00:35:26This may mean that there are

00:35:28more planets in poor metal systems

00:35:30than we thought.

00:35:32The students will help us

00:35:34learn more about the formation of planets.

00:35:36Imagine.

00:35:38You float in the depths of space

00:35:40and you see our dear blue planet.

00:35:42Who is at the top?

00:35:44You may think it is the North Pole,

00:35:46but it is not necessarily the case.

00:35:48In fact, this collective belief

00:35:50that the North would be at the top of the world

00:35:52is not based on any solid scientific basis.

00:35:54It is simply

00:35:56one thing that we have accepted

00:35:58over time.

00:36:00And this convention has a fascinating history.

00:36:02With a suspicion of astrophysics,

00:36:04a little psychology and a surprising consequence,

00:36:06it influences our perception

00:36:08of the world much more than we think.

00:36:10Knowing where we are

00:36:12is essential to survival.

00:36:14And it is true for most species.

00:36:16Not just for us humans.

00:36:18Like bees,

00:36:20for example,

00:36:22human beings have the ability

00:36:24to create mental maps of their environment.

00:36:26But where we really stand out

00:36:28is in our efforts

00:36:30to share these maps

00:36:32with our fellow humans.

00:36:34We started doing it some time ago

00:36:36by drawing maps on all kinds of supports,

00:36:38from cave walls

00:36:40to computer screens.

00:36:42The oldest we have found

00:36:44date back to nearly 14,000 years.

00:36:46Despite this long evolution,

00:36:48it was only in the last centuries

00:36:50that we decided that the North

00:36:52should always be at the top of the map.

00:36:54History books will teach us

00:36:56that for a long time,

00:36:58the North was practically never

00:37:00placed at the top of the map

00:37:02because it symbolized darkness.

00:37:04The West was not taken into account either.

00:37:06Because that's where the sun

00:37:08died every night.

00:37:10However, the first Asian maps

00:37:12seem to question this trend.

00:37:14Before you think about it,

00:37:16no,

00:37:18it's not because of their compass

00:37:20that they placed the North at the top of the map.

00:37:22The first Asian compasses

00:37:24were actually aligned to the South,

00:37:26considered a more favorable direction

00:37:28than the cold and darkness of the North.

00:37:30But on these maps,

00:37:32the emperor,

00:37:34who resided in the North,

00:37:36was always placed at the top.

00:37:38It's a faithful subject,

00:37:40looking up at him.

00:37:42In retrospect,

00:37:44each culture had its own notion of CE,

00:37:46towards which it was better to be turned,

00:37:48which led to varied orientations

00:37:50of the first maps.

00:37:52The Egyptians preferred the East,

00:37:54where the sun gratifies us

00:37:56with its appearance every morning.

00:37:58The first Arab maps

00:38:00were placed in the South.

00:38:02The European maps of the same time

00:38:04placed the East at the top.

00:38:06When did everyone decide

00:38:08that the North was the new top of the world?

00:38:10We could be tempted to attribute

00:38:12paternity to explorers

00:38:14like Christophe Colomb and Magellan,

00:38:16who oriented themselves

00:38:18according to the polar star.

00:38:20But they didn't really see the world

00:38:22from this angle.

00:38:24Christophe Colomb, for example,

00:38:26saw the world with the East at its top,

00:38:28and the 1569 report changed that,

00:38:30because it was the first to take into account

00:38:32the curvature of the Earth

00:38:34for more precise navigation.

00:38:36But even at that time,

00:38:38the emphasis was not put on the North.

00:38:40Mercator projected the poles to infinity,

00:38:42considering them as relatively unimportant

00:38:44since the sailors never ventured there.

00:38:46It is possible that the choice

00:38:48to place the North at the top

00:38:50was motivated by the fact that the Europeans,

00:38:52who accomplished their part of exploration,

00:38:54were in the northern hemisphere,

00:38:56so they had much more land to cover

00:38:58and people to hang out with.

00:39:00Whatever the reason,

00:39:02this idea of the North at the top

00:39:04remained.

00:39:06Even when a NASA astronaut

00:39:08took a picture of the Earth

00:39:10with the South as its summit in 1972,

00:39:12it had to be turned around

00:39:14to avoid any confusion.

00:39:16This is where things get interesting.

00:39:18When you observe the Earth from space,

00:39:20the notions of up and down

00:39:22lose all their meaning.

00:39:24We all share the same cosmic origin,

00:39:26but we could just as well

00:39:28reverse the image

00:39:30or place the sun up or down,

00:39:32depending on the astronomical point of view.

00:39:34Even within the Milky Way,

00:39:36our solar system is tilted

00:39:38by about 63 degrees.

00:39:40If we think about it,

00:39:42the notions of up, down, left and right

00:39:44do not really apply to space.

00:39:48But why not reverse it?

00:39:50Should we accept to see our world

00:39:52from a different angle?

00:39:54There is psychological evidence

00:39:56that our Nordic mentality

00:39:58could mislead our perceptions of value.

00:40:00Most people consider

00:40:02that the North is up

00:40:04and the South is down.

00:40:06Psychologists even wondered

00:40:08if these associations could influence

00:40:10the way people consider

00:40:12the different places on the map.

00:40:14When they were shown the map

00:40:16of a fictional city,

00:40:18people were more inclined

00:40:20to place the rich in the North

00:40:22and the poor in the South.

00:40:24It is not an exaggeration

00:40:26to assume that humans

00:40:28care less about those

00:40:30who arrive in the lower regions

00:40:32than about those

00:40:34where they are on the map.

00:40:36But there is a simple solution.

00:40:38Reverse the map.

00:40:40Experiments have shown

00:40:42that this simple action

00:40:44eliminates the bias

00:40:46according to which the North

00:40:48and the South are already available online.

00:40:50The Australians would appreciate

00:40:52this change, it is certain.

00:40:54Whatever you prefer,

00:40:56at the top of your world map,

00:40:58you will need a compass

00:41:00to guide you.

00:41:02Have you ever stopped

00:41:04to think about this system?

00:41:06It is one of the oldest gadgets

00:41:08we have in our survival kit.

00:41:10It has existed for centuries

00:41:12as a lighthouse for adventurers,

00:41:14travelers and other explorers,

00:41:16and in fact,

00:41:18the compass has transformed

00:41:20the sedentary man

00:41:22into a nomad globetrotter.

00:41:24Our beautiful blue planet

00:41:26is not only a sphere

00:41:28that spins in the cosmos,

00:41:30it also has its own magnetic field.

00:41:32Imagine it as a colossal magnet

00:41:34swarming with an invisible energy.

00:41:36All this thanks to the core of the Earth,

00:41:38a fusion iron ball

00:41:40subjected to a colossal pressure

00:41:42in the center of our planet.

00:41:44The solid half-crystal ball

00:41:46vibrates and swirls

00:41:48under the effect of the planet's rotation,

00:41:50thus creating this magnetic field

00:41:52that gives us our poles

00:41:54North and South.

00:41:56But that's where things get a little tricky.

00:41:58These magnetic poles are not perfectly

00:42:00aligned with the geographic poles

00:42:02of the Earth, those around which

00:42:04the Earth rotates.

00:42:06They are close, of course,

00:42:08but are not exactly

00:42:10in the same place.

00:42:12The magnetic poles

00:42:14that react to the magnetic field

00:42:16do not point directly towards

00:42:18what we call the true North,

00:42:20that is, the geographic North Pole.

00:42:22They rather point towards the magnetic North,

00:42:24located a little below the real one.

00:42:26But don't worry,

00:42:28it is close enough to bring us

00:42:30where we need to go.

00:42:32Let's talk a little more about this story

00:42:34of the true North and the magnetic North.

00:42:36Do you remember the September news

00:42:38in 2019 that claimed that,

00:42:40for more than 360 years,

00:42:42the Greenwich compasses

00:42:44indicated the true North?

00:42:46This is a rather rare fact.

00:42:48In general, the compasses indicate

00:42:50the magnetic North, which is not

00:42:52a constant point on the map.

00:42:54They change and drift over time

00:42:56depending on the movements

00:42:58of the Earth's core.

00:43:00On the other hand, the geographic North

00:43:02refers to the geographic North Pole,

00:43:04a precise and immutable point

00:43:06on the surface of the Earth.

00:43:08This is where things

00:43:10become even more curious.

00:43:12The angle between the direction

00:43:14of the geographic North

00:43:16and that of the magnetic North

00:43:18indicated by the compass

00:43:20is called magnetic declination.

00:43:22It is a sophisticated word

00:43:24for a simple concept.

00:43:26Now, as the Earth's magnetic field

00:43:28is not an easily apprehensible thing,

00:43:30it has its hollows and its oscillations,

00:43:32the declination is not the same everywhere.

00:43:34It varies from one place to another.

00:43:36The compass is equipped

00:43:38with a tiny needle

00:43:40designed from a magnetized metal,

00:43:42iron being the most common.

00:43:44This needle is fixed

00:43:46on a small pointy element,

00:43:48or pivot, and left floating

00:43:50in any liquid, often mineral oil

00:43:52or something similar.

00:43:54This allows the needle to rotate

00:43:56and dance with the Earth's magnetic field.

00:43:58When you hold your flat compass

00:44:00in your hand, the needle stabilizes

00:44:02and indicates the magnetic North.

00:44:04Look at your compass and you will notice

00:44:06these little marks. These are the degrees.

00:44:08And here is how to read it.

00:44:10The red end of the needle always points

00:44:12to the North, and the white or black end

00:44:14always points to the South.

00:44:16It is the North-South dance of your compass.

00:44:18In addition, the compass chassis

00:44:20often has an arrow at the top.

00:44:22It is the orientation arrow.

00:44:24What you admire here is by far

00:44:26the most successful portrait of our sun.

00:44:28Fortunately, our star,

00:44:304.5 billion years old,

00:44:32did not use makeup to arrange

00:44:34its hue before this photo session.

00:44:36And we can now study its surface in detail.

00:44:38This emblematic cliché

00:44:40was taken in March 2022.

00:44:42NASA wanted to acquire a better understanding

00:44:44of the behavior of our star

00:44:46and its impact on terrestrial life.

00:44:48And consider the future of our space technologies,

00:44:50of course.

00:44:52To do this, we launched the satellite

00:44:54of the Solar Dynamics Observatory,

00:44:56or SDO, in February 2010.

00:44:58This legendary photo session

00:45:00took place 12 years later,

00:45:02when the SDO was halfway between

00:45:04the Earth and the Sun.

00:45:06Researchers had to assemble 25 individual images

00:45:08in the form of a puzzle.

00:45:10Thus, the final image contains 83 million pixels.

00:45:12And yes, this resolution

00:45:14is about ten times higher

00:45:16than that of the screen of your 4K TV.

00:45:18Look at this incredible pattern

00:45:20reminiscent of the crust of a biscuit.

00:45:22Usually, the sparkling surface of the Sun

00:45:24hides it from us when we observe

00:45:26the star from Earth.

00:45:28But recently, NASA has explored

00:45:30this light beyond the observable spectrum,

00:45:32which allowed it to discover

00:45:34invisible details of the face of our Sun.

00:45:36When we adjust a selfie

00:45:38with filters and effects,

00:45:40we can get completely different portraits,

00:45:42highlighting different parts

00:45:44of our face.

00:45:46Even those we didn't even know existed.

00:45:48The same principle applies here.

00:45:50Each of these plasma balls

00:45:52is the same photo of the Sun,

00:45:54captured at different electromagnetic wavelengths.

00:45:56These images and the patterns revealed

00:45:58can help us understand a little better

00:46:00the events that occur under the skin of our star.

00:46:02At the speed of light,

00:46:04it usually means something extremely fast.

00:46:06However, this golden pink ray

00:46:08that caresses your cheek at dawn

00:46:10has traveled a long way

00:46:12and is incredibly old on a human scale.

00:46:14The photons generated by the core of the Sun

00:46:16take between 10,000 and 170,000 years

00:46:18to cross the atmosphere of the star,

00:46:20then about eight more minutes

00:46:22to reach Earth.

00:46:24Why does it take them so long?

00:46:26Our visit begins with the upper layer

00:46:28of the atmosphere of the Sun.

00:46:30Do you see these solar deities

00:46:32in the paintings and theater pieces

00:46:34of the Baroque era?

00:46:36They often wear luxurious crowns

00:46:38with gold-plated rays.

00:46:40Well, the Sun itself also wears

00:46:42a beautiful crown,

00:46:44which is the external layer of its atmosphere.

00:46:46But of course, its greatness and glory

00:46:48are incomparable to those of these

00:46:50cardboard costume crowns,

00:46:52which envelop our star,

00:46:54so that its size and shape fluctuate

00:46:56constantly under the influence

00:46:58of the magnetic field of the Sun.

00:47:00You can see this crown of your own eyes

00:47:02from Earth during total solar eclipses.

00:47:04It looks like a sublime radiation

00:47:06around the solar disk,

00:47:08which itself is then completely

00:47:10masked by the Moon.

00:47:12The crown extends over 8 million kilometers

00:47:14above the surface of the Sun,

00:47:16while our blue planet

00:47:18measures only 13,000 kilometers in diameter.

00:47:20The hypothetical radius of the crown

00:47:22would be equivalent to a line of about

00:47:24625,000 planets the size of the Earth.

00:47:26And suddenly, all my problems

00:47:28begin to seem tiny.

00:47:30And here is another singular fact.

00:47:32The crown of the Sun somehow derogates

00:47:34the laws of known physics,

00:47:36because it is warmer than it should be.

00:47:38Its temperature is more than

00:47:401 million degrees Celsius,

00:47:42while the surface of the Sun is only

00:47:44about 5,000 degrees.

00:47:46That said, the adverb only is not

00:47:48because it is still extremely hot

00:47:50in human terms.

00:47:52Usually, the temperature tends to drop

00:47:54when we move away from a source of heat.

00:47:56But this is not the case here.

00:47:58Astrophysicists remain perplexed

00:48:00in the face of such a mystery.

00:48:02Fortunately, this recent photo session

00:48:04allows us to discover what is happening

00:48:06inside this huge incandescent ball

00:48:08without risking losing sight of it.

00:48:10Take, for example, these magnificent bright spots.

00:48:12They represent the solar eruptions

00:48:14that occur under the layer of the crown.

00:48:16These are powerful explosions

00:48:18that occur when magnetic fields

00:48:20collide with each other.

00:48:22When they take place,

00:48:24they change shape and react quickly.

00:48:26These magnetic fields come from plasma,

00:48:28which is itself very turbulent,

00:48:30so that such events are not

00:48:32surprising for the local weather.

00:48:34Who would have thought that the Sun

00:48:36had black spots on its skin,

00:48:38just like teenagers?

00:48:40These darker areas are known

00:48:42as coronal holes.

00:48:44We can see the impact

00:48:46when we observe these magnificent auroras

00:48:48in the polar regions.

00:48:50The coronal holes seem darker

00:48:52because the plasma in these regions

00:48:54is colder, less dense,

00:48:56and open magnetically.

00:48:58These conditions allow the solar wind

00:49:00to spread through the solar system

00:49:02rather than stay on the surface of the star.

00:49:04And when they hit the Earth's magnetosphere,

00:49:06these auroras form to delight our eyes.

00:49:08Fortunately, our local magnetic field

00:49:10cools the solar winds.

00:49:12No one would want to see their eyes melt, right?

00:49:14Now, if we were looking for

00:49:16an equivalent to the hair of the Sun,

00:49:18the best candidates would be

00:49:20the solar protuberances.

00:49:22These large loops of bright plasma

00:49:24rise from the surface of the Sun

00:49:26and stretch over thousands of kilometers

00:49:28in space. Their lifespan varies

00:49:30from a few days to several months.

00:49:32It is one of the most common events

00:49:34in this region.

00:49:36Although the first detailed description

00:49:38of a solar protuberance dates from the 14th century,

00:49:40modern scientists are still looking for

00:49:42how and why they form.

00:49:44By diving deeper,

00:49:46we are confronted with the transition zone.

00:49:48The thickness of this layer is about 100 kilometers.

00:49:50And the local weather is

00:49:52purely magnetic.

00:49:54Temperatures can rise up to 500,000 degrees.

00:49:56This transition zone is located

00:49:58between the crown and the last region

00:50:00of the atmosphere of the Sun,

00:50:02which is called the chromosphere.

00:50:04Speaking of which, this is precisely

00:50:06our next stop.

00:50:08I would like to present a scientific mystery

00:50:10called spikule. Repeat it 20 times very quickly.

00:50:12Spikule, spikule, spikule.

00:50:14It's funny, isn't it?

00:50:16This spectacular plasma jet

00:50:18stretches from the surface of the Sun

00:50:20and reaches speeds

00:50:22of about 360 km per second.

00:50:24As if they were jumping on a trampoline

00:50:26from the surface of the Sun.

00:50:28Each spikule lasts a few minutes

00:50:30in space before falling back

00:50:32into the solar atmosphere.

00:50:34Astrophysicists had a hard time explaining

00:50:36how magnetically charged particles

00:50:38could escape the incredible gravity

00:50:40of the Sun while being so close to it.

00:50:42A possible answer

00:50:44appeared in 2017.

00:50:46A group of scientists discovered

00:50:48that neutral particles provided

00:50:50magnetically charged particles

00:50:52with additional buoyancy

00:50:54allowing them to tear away at solar gravity

00:50:56for a while.

00:50:58Which is still better than the explanation

00:51:00of the pearly powder, isn't it?

00:51:02Let's now go 1,600 km

00:51:04in the chromosphere to finally reach

00:51:06the solar surface or photosphere.

00:51:08It measures about 400 km in thickness.

00:51:10But unlike the planet Earth,

00:51:12the surface of the Sun

00:51:14is neither stable nor solid.

00:51:16The temperatures here are so high

00:51:18that no matter can exist.

00:51:20On the other hand,

00:51:22scientists often call plasma

00:51:24the fourth state of matter.

00:51:26And why not?

00:51:28It is made up of ionized atoms

00:51:30and free electrons.

00:51:32They are considered as such.

00:51:34Maybe one day,

00:51:36we will have the opportunity

00:51:38to meet a local species

00:51:40of plasmoid people.

00:51:42But I think it would be better

00:51:44if we avoided their warm

00:51:46welcome.

00:51:48You know,

00:51:50such people would surely

00:51:52have a volcanic temperament.

00:51:54Anyway, the photosphere

00:51:56is our last step

00:51:58because humanity does not yet

00:52:00have a spacecraft.

00:52:02But time is running out.

00:52:04You only have 7 to 8 billion years.

00:52:06After that, our sun will go out,

00:52:08according to the estimates of scientists.

00:52:10And to tell the truth,

00:52:12these same scientists

00:52:14will surely be the first on the shot.

00:52:16You have a serious competitor.

00:52:18The solar probe Parker of NASA

00:52:20currently holds the record

00:52:22of the deepest dive in our sun.

00:52:24This spacecraft has managed

00:52:26to travel 7,300,000 km

00:52:28since September 8, 2023.

00:52:30And since then, the Parker probe

00:52:32has reiterated the feat in December

00:52:34of the same year.

00:52:36So why didn't it melt,

00:52:38you may ask.

00:52:40The probe was designed to resist

00:52:42the most extreme conditions

00:52:44and temperature fluctuations.

00:52:46It is equipped with a custom thermal shield

00:52:48and an autonomous system

00:52:50protecting the mission

00:52:52against intense solar radiation.

00:52:54NASA has other ambitious plans.

00:52:56The probe will travel even closer to the sun.

00:52:58It will move faster than any other object

00:53:00man-made,

00:53:02at a speed of 700,000 km per hour.

00:53:04The probe will then be

00:53:06only 6 million km

00:53:08from the burning surface of the sun.

00:53:10It's practically like landing on a star.

00:53:12Astronomers have already compared

00:53:14this next step to our first landing.

00:53:16Finally, it would probably be better

00:53:18if we landed at night.

00:53:20Okay, I admit it.

00:53:22It's an old joke like the world.

00:53:241994

00:53:26It was dark,

00:53:28so that no one noticed the two silhouettes

00:53:30opening the emergency exits

00:53:32of a glass dome complex

00:53:34located in Arizona and known as

00:53:36Biosphere 2.

00:53:38They were determined to free 7 people

00:53:40locked inside for a month,

00:53:42risking their lives in the name of science.

00:53:44The mission was a success,

00:53:46but they were accused of property

00:53:48and vandalism.

00:53:50The vandals were Tabi Ghaelaling

00:53:52and Marc Ventillo.

00:53:54They were among the first 8

00:53:56to live in this place, like guinea pigs.

00:53:58And they didn't want others

00:54:00to suffer the same horrors they had.

00:54:02150 million dollars were spent

00:54:04to determine if humans

00:54:06could create suitable living conditions

00:54:08on other planets, like Mars.

00:54:10To do this, scientists

00:54:12built a mini-world with more than

00:54:143,000 species of plants and animals.

00:54:16Biosphere 2 was a 12,000 m2 habitat,

00:54:18completely isolated,

00:54:20with its own mini-tropical forest,

00:54:22a private beach with a coral reef,

00:54:24a small savannah,

00:54:26a swamp,

00:54:28and even a piece of desert.

00:54:30Between 1991 and 1993,

00:54:32nothing could enter or leave this place.

00:54:34The group of 8 people

00:54:36locked inside were called

00:54:38the Biospherians,

00:54:40and wore suits

00:54:42like Star Trek,

00:54:44growing their own food

00:54:46and breathing their own air.

00:54:48They had no hope

00:54:50and a breakfast worthy

00:54:52of a 5-star hotel.

00:54:54But things took a dark turn

00:54:56over the months.

00:54:58All the team died of hunger

00:55:00and turned orange.

00:55:02In Biosphere 1,

00:55:04which is our good old Earth,

00:55:06you can order a pizza in 2 minutes.

00:55:08But inside Biosphere 2,

00:55:10it took them 4 endless months

00:55:12to prepare a margherita.

00:55:14They had to harvest wheat for the dough

00:55:16and they became an integral part

00:55:18of their atmosphere, literally.

00:55:20When they exhaled,

00:55:22their carbon dioxide fed

00:55:24the sweet potatoes they grew.

00:55:26And these sweet potatoes

00:55:28became a part of themselves,

00:55:30since they ate essentially

00:55:32the same carbon over and over again.

00:55:34They ate so many sweet potatoes

00:55:36that their skin turned orange

00:55:38because of all this excess beta-carotene.

00:55:40What seemed to be a funny situation

00:55:42at the time,

00:55:44was that the agricultural yields

00:55:46in Biosphere 2 were extremely disappointing.

00:55:48And the team died of hunger.

00:55:50Hunger drove them crazy

00:55:52and sudden fits of anger

00:55:54led them to do regrettable things,

00:55:56like stealing bananas in the basement.

00:55:58After a while,

00:56:00the freezer had to be locked.

00:56:02During the first 6 months,

00:56:04each of them lost between 8 and 26 kilos.

00:56:06Every day, someone was in charge

00:56:08of weighing the fresh food for the cook,

00:56:10delivering all the information

00:56:12to ensure that the crew

00:56:14reached their recommended yields

00:56:16in calories, protein and fat.

00:56:18At first,

00:56:20meals were served in the form of buffets.

00:56:22But as the food began to run out,

00:56:24the cooks began to

00:56:26meticulously divide their food

00:56:28into equal portions.

00:56:30Their diet,

00:56:32mainly sweet potatoes, carrots, fruits

00:56:34and occasionally meat on Sundays,

00:56:36was supposed to allow them to hold

00:56:38during these exhausting 80-hour weeks,

00:56:40exhausted from manual work.

00:56:42The biospherists left each meal

00:56:44still hungry

00:56:46and had recurring dreams of Big Mac,

00:56:48sushi, chocolate bars

00:56:50and other cakes.

00:56:52The air began to be lacking.

00:56:54The place was completely sealed

00:56:56with a dome of glass and steel at the top

00:56:58and a floor made of the same metal at the bottom.

00:57:00The managers made sure to control

00:57:02everything that entered,

00:57:04to prevent synthetic materials

00:57:06from emitting harmful gases.

00:57:08The rooms were furnished

00:57:10with wood and wool

00:57:12and could not be used

00:57:14for chemical deodorants

00:57:16or birthday candles.

00:57:18The biospherists counted

00:57:20on the food they grew

00:57:22and on their mini tropical forest

00:57:24to produce the oxygen

00:57:26necessary for their survival.

00:57:28However, they quickly lost oxygen,

00:57:30suffocated by their own

00:57:32carbon dioxide emissions.

00:57:34And the worst part

00:57:36their oxygen levels had already fallen

00:57:38from 21 to about 15%,

00:57:40which gave the impression of living

00:57:42at the top of Mount Fuji.

00:57:44They felt terribly bad

00:57:46and dragged painfully through the biosphere.

00:57:48They couldn't even finish

00:57:50a sentence without stopping

00:57:52to catch their breath.

00:57:54Then the apnea of sleep began to appear,

00:57:56some waking up out of breath.

00:57:58To reduce the CO2 levels

00:58:00inside Biosphere 2,

00:58:02they tried some desperate maneuvers,

00:58:04such as pushing plants at a crazy pace,

00:58:06reducing as much as possible

00:58:08soil watering,

00:58:10and even giving up plowing their crops.

00:58:12Nothing worked.

00:58:14So everyone agreed

00:58:16that they were not far from the bottom.

00:58:18And so they decided to ask for help.

00:58:20Refrigerated trucks arrived

00:58:22to pump pure oxygen into Biosphere 2.

00:58:24As soon as the gas began to spread,

00:58:26they started laughing out loud

00:58:28and running everywhere like cabrioles.

00:58:30The ecosystem was a real disaster.

00:58:32Herbivores and bees disappeared

00:58:34after a few months,

00:58:36so that the plants were no longer pollinated.

00:58:38Worms and acarians

00:58:40attacked crops,

00:58:42and cockroaches invaded everything.

00:58:44Four species of cockroaches

00:58:46were introduced to recycle organic matter,

00:58:48but ordinary domestic cockroaches

00:58:50were the ultimate survivors.

00:58:52They managed to infiltrate

00:58:54and multiply,

00:58:56posing a serious threat to crops.

00:58:58At night, the kitchen was invaded

00:59:00To fight this infestation,

00:59:02the group greased coffee cups

00:59:04with lubricant

00:59:06and put pieces of papaya

00:59:08to serve as bait.

00:59:10The cockroaches climbed inside,

00:59:12but could no longer climb

00:59:14the sliding edges to escape.

00:59:16Being hungry, lacking oxygen,

00:59:18facing insect infestations,

00:59:20it would be enough to drive anyone crazy.

00:59:22Violent disputes led people

00:59:24to throw cups at each other

00:59:26and spit on each other.

00:59:28They stopped talking to each other

00:59:30and could meet in the corridors

00:59:32without even looking at each other.

00:59:34Half of them wanted more food

00:59:36and oxygen to continue

00:59:38the experiment with dignity,

00:59:40while the other half believed

00:59:42in their chance of survival

00:59:44without external help and whatever it costs.

00:59:46In truth, the sealed room

00:59:48had been violated long before all this.

00:59:50Just two weeks after their entry,

00:59:52a biospheric woman named Jane Poynter

00:59:54had cut her finger

00:59:56in a kitchen accident while preparing rice.

00:59:58The doctor on the mission

01:00:00tried to sew it up, but it didn't work

01:00:02and her finger turned black in a few days.

01:00:04She went to an outside hospital

01:00:06to be operated on,

01:00:08and a few hours later,

01:00:10she returned inside with a sport bag

01:00:12filled with supplies such as

01:00:14computer parts and colored films.

01:00:16Journalists only discovered

01:00:18this stealth delivery many months later.

01:00:20And because of this,

01:00:22many people questioned

01:00:24the credibility of the whole experiment.

01:00:26The media treated the experiment

01:00:28as a reality TV show,

01:00:30calling it

01:00:32ecological entertainment.

01:00:34The big titles from all over the world

01:00:36made the impression that the team

01:00:38was about to die.

01:00:40To the point that their families were worried

01:00:42and kept calling the biospheric people

01:00:44to make sure they were doing well.

01:00:46The group had the impression of being

01:00:48in a human zoo, with tourists

01:00:50coming from afar to watch them

01:00:52from their glass cage.

01:00:54In just the first six months,

01:00:56more than 150,000 people visited the place.

01:00:58Biosphere 2 ended up

01:01:00becoming a gag in popular culture,

01:01:02inspiring a comedy called

01:01:04Biodome and decades of funny sketches.

01:01:06You may be wondering

01:01:08why none of them gave up the experiment

01:01:10and didn't go out the front door.

01:01:12Well, none of the environmentalists

01:01:14wanted to be the first to admit

01:01:16that it was beyond their strength.

01:01:18In addition, they still kept

01:01:20all hope of being able to

01:01:22challenge the construction of a second Earth.

01:01:24In the end, they managed

01:01:26to discover where the

01:01:287 tons of oxygen was missing.

01:01:30It had been absorbed by the concrete.

01:01:32Even if being out of breath all the time

01:01:34may seem to have been the biggest challenge

01:01:36they had to face,

01:01:38the biospheric people declared that

01:01:40learning human contact in a closed environment

01:01:42was even more difficult.

01:01:44It seems that the experience was a huge fiasco.

01:01:46But the group has learned

01:01:48a lot of valuable lessons.

01:01:50They proved that a sealed ecosystem

01:01:52could work for years.

01:01:54They contributed to studies on the restoration

01:01:56of coral reefs.

01:01:58And their farm showed that a high yield

01:02:00and a complete recycling of nutrients

01:02:02could be achieved without the help

01:02:04of chemical products.

01:02:06In case you were wondering,

01:02:08it wasn't the end of the glass complex.

01:02:10The second mission inside Biosphere 2

01:02:12took place in March 1994.

01:02:14Now, you can go back

01:02:16to the beginning of the video

01:02:18to understand how it could have happened for them.

01:02:20Have you ever heard of the diamond star

01:02:22whose value exceeds

01:02:24that of all the riches of the Earth?

01:02:26Or of these sparkling stars whose surface

01:02:28is made of solid iron?

01:02:30Let's take a look at these strange stars

01:02:32and try to solve their mystery.

01:02:38There is a star in the Centaur constellation

01:02:40nicknamed Lucy in the sky with diamonds.

01:02:42Yes, this is the title

01:02:44of a Beatles song.

01:02:46We discovered that this star

01:02:48contained a massive diamond

01:02:50in its core.

01:02:54But you may be wondering

01:02:56what is the real size of this diamond?

01:02:58Well, it is estimated

01:03:00to be about 10 billion billion

01:03:02carats.

01:03:04A 1 followed by 34 zeros.

01:03:06To put this into perspective,

01:03:08the diamond Hope

01:03:10one of the largest diamonds on Earth

01:03:12is only 45.5 carats.

01:03:14Can you imagine

01:03:16the size of the ring

01:03:18that you could make

01:03:20with this stellar diamond?

01:03:22And it has about the same mass

01:03:24as our sun.

01:03:26But don't get carried away

01:03:28with the idea of owning this diamond.

01:03:30Even if you were Jeff Bezos,

01:03:32you couldn't afford it.

01:03:34According to Ronald Winston,

01:03:36CEO of Harry Winston,

01:03:38the size of this diamond

01:03:40would risk dropping

01:03:42the prices of the market.

01:03:44So you'll have to settle

01:03:46for a ring much smaller.

01:03:50An interesting thing

01:03:52about Lucy in the sky with diamonds

01:03:54is that it is incredibly dense.

01:03:56Its mass is that of the sun,

01:03:58but within a diameter

01:04:00equivalent to one third of that of the Earth.

01:04:02As if you were trying

01:04:04to get an elephant

01:04:06out of a shoebox.

01:04:08And yet, despite this imposing size,

01:04:10it is relatively cold,

01:04:12with a central temperature

01:04:14of about 6,649 ° C only.

01:04:16In comparison,

01:04:18the central temperature of our sun

01:04:20is about 15 million degrees.

01:04:24Since the discovery

01:04:26of Lucy in the sky with diamonds,

01:04:28we have found several other crystallized stars,

01:04:30some of which have a diamond heart

01:04:32the size of the Earth.

01:04:34This proves that the universe

01:04:36is full of surprises,

01:04:38and that we never know

01:04:40what kind of treasure

01:04:42we will discover

01:04:44in the vast expanse of space.

01:04:46We have found

01:04:48other curious stars.

01:04:50There are many strange

01:04:52and unexplained things

01:04:54in space.

01:04:56Let's take the example of Vega.

01:04:58Vega, also called Alpha Lyrae,

01:05:00is a star located

01:05:02in the Northern Hemisphere.

01:05:04It is one of the brightest stars

01:05:06in the night sky,

01:05:08and it is easily visible to the naked eye

01:05:10in most regions of the world.

01:05:12For us,

01:05:14inhabitants of the Northern Hemisphere,

01:05:16Vega is a beautiful luminous star.

01:05:18But we have discovered

01:05:20one of its secrets.

01:05:22It is actually a little crushed.

01:05:24Its rotational speed

01:05:26makes it swell to the equator,

01:05:28as if it had a little belly.

01:05:32It rotates once every 12.5 hours,

01:05:34which is quite fast for a star.

01:05:36And it projects matter

01:05:38around it.

01:05:40It's a bit like making hula hoop.

01:05:42This matter,

01:05:44being quite far from its center,

01:05:46therefore undergoes less gravity,

01:05:48which cools it and darkens it.

01:05:50This is called darkening

01:05:52by gravity.

01:05:56Vega is therefore the worst nightmare

01:05:58of a cosmic fitness advisor.

01:06:00For us who observe it,

01:06:02it always seems round,

01:06:04because we look at it from the end

01:06:06of the Earth's pole.

01:06:08If we observed it from another angle,

01:06:10we would have a very different view.

01:06:12And we would wonder

01:06:14if Vega does not swell

01:06:16from a cosmic bath

01:06:18when we turn its back.

01:06:20But even if we make fun

01:06:22of its size,

01:06:24it is undeniable that Vega

01:06:26remains one of the most fascinating

01:06:28objects in the universe.

01:06:32But you want to see something really bright?

01:06:34What would you say about a supernova?

01:06:38Supernovas are gigantic explosions

01:06:40that occur when stars

01:06:42reach the end of their lives.

01:06:46It's like the final bouquet of a firework,

01:06:48but on a cosmic scale.

01:06:50It releases more energy in a few seconds

01:06:52than our sun will produce

01:06:54for its entire life.

01:06:58And that's exactly what happened

01:07:00to the star we are going to see now.

01:07:02A celestial object

01:07:04named IPFT-I4HLS.

01:07:08But there is a hiccup.

01:07:10It is not an ordinary supernova.

01:07:12This star exploded well in 2014

01:07:14and began to go out

01:07:16as expected.

01:07:18But then it started to shine again.

01:07:22You are talking about a stage entrance.

01:07:24And as if that were not enough,

01:07:26it continued to go out

01:07:28and then lit up at least five times in total.

01:07:30A bit like a yo-yo.

01:07:32It's as if it couldn't decide

01:07:34whether it wanted to keep shining

01:07:36or go out forever.

01:07:40In addition,

01:07:42when scientists measured

01:07:44the spectrum of this supernova,

01:07:46they found that it evolved

01:07:48ten times slower than other stars.

01:07:50Maybe they just want to

01:07:52enjoy a bit of their old age.

01:07:58In short,

01:08:00this object is a real mystery.

01:08:04But it is not the only star

01:08:06suffering from two-in-one syndrome.

01:08:08At first glance,

01:08:10MY Camelopardalis

01:08:12seems quite ordinary.

01:08:14But looking at it more closely,

01:08:16astronomers have discovered

01:08:18that it was actually two stars.

01:08:22They rotate around each other

01:08:24at more than 950,000 km per hour.

01:08:28It is a binary stellar system

01:08:30in contact,

01:08:32which means that the stars are

01:08:34so close to each other

01:08:36that they share a common envelope.

01:08:38In other words,

01:08:40they are so close

01:08:42that they are literally beckoning each other.

01:08:44These Romeo and Juliet stars

01:08:46are one of the most massive

01:08:48binary stars known.

01:08:50They have a total mass of

01:08:522.38 solar masses.

01:08:56And our astronomers

01:08:58think they could be

01:09:00about to merge.

01:09:02Which means that one day

01:09:04they could combine

01:09:06to form a super giant star.

01:09:08Who would have thought

01:09:10that space could be so romantic?

01:09:12Here is now

01:09:14another name for it.

01:09:16HD 140283

01:09:18L'étoile Mathusalem

01:09:20This little man

01:09:22in the constellation of the balance

01:09:24has existed for a while.

01:09:26And by a while, I mean a very, very long time.

01:09:28In fact, scientists thought

01:09:30it was older than the universe itself.

01:09:36Imagine if that was true.

01:09:38But they ended up discovering

01:09:40that it was about 14 billion years old.

01:09:42That is, the same age

01:09:44as our universe.

01:09:46It is still quite impressive.

01:09:48It is so old that it remembers

01:09:50the time when the Milky Way

01:09:52was just a small galaxy.

01:09:56Despite everything,

01:09:58it still has a little life in it.

01:10:00It is just starting

01:10:02to turn into a red giant.

01:10:04Which is a bit like when you reach

01:10:06thirty. So it is getting old quite well.

01:10:10But if all these things

01:10:12remain more or less understandable,

01:10:14what about this star

01:10:16that astronomers have nicknamed WTF?

01:10:18Or what is this thing?

01:10:20Today we call it

01:10:22Tabby's star.

01:10:24It also has a more scientific name.

01:10:26But it is a bit long.

01:10:32What is really weird about it

01:10:34is its irregular brightness.

01:10:36For some unknown reason,

01:10:38it does not shine like a normal star.

01:10:40It flashes, like when you turn on

01:10:42a flashlight.

01:10:44And it is not a decrease in brightness,

01:10:46but a fall of 22%.

01:10:48So it is not because

01:10:50an object comes to hide it from time to time.

01:10:54Scientists have

01:10:56all kinds of theories about this strange behavior.

01:10:58Comets,

01:11:00dust, an extraterrestrial

01:11:02megastructure.

01:11:04Yes, but before

01:11:06your imagination goes wild,

01:11:08it is important to note that the most

01:11:10probable explanation is that of dust.

01:11:12The star would be surrounded

01:11:14by a kind of cloud of dust

01:11:16that would sometimes prevent us

01:11:18from seeing it clearly.

01:11:22But this explanation is not yet

01:11:24100% confirmed.

01:11:26And there is still a lot of mystery

01:11:28about Tabby's star.

01:11:30One thing is for sure,

01:11:32it may be a bit weird,

01:11:34but that's what makes it so fascinating.

01:11:36And there you go, my friend.

01:11:38We are amazed

01:11:40by the incredible diversity

01:11:42and strangeness of the cosmos.

01:11:44There are still so many things to discover,

01:11:46so let's continue to explore the universe

01:11:48in search of these fabulous treasures.

01:11:52Ladies and gentlemen,

01:11:54this is your captain speaking to you.

01:11:56We will be ready to take off in 3,

01:11:582, 1.

01:12:00Living in a spaceship

01:12:02looks like the dream subject of a science fiction movie,

01:12:04but it is gradually becoming clearer

01:12:06than the plan envisaged for a distant future.

01:12:08Let's imagine what it would be.

01:12:10Without further ado,

01:12:12we will start with light.

01:12:14On Earth, thanks to the atmosphere,

01:12:16the sky disperses the light of the sun.

01:12:18We therefore receive light

01:12:20from different directions.

01:12:22There are then shadows,

01:12:24contrast and ambient light.

01:12:26In a spaceship, however,

01:12:28there is no sky to create this ambient light.

01:12:30When you are in a spaceship

01:12:32inside the solar system,

01:12:34one side of the ship can be lit by the sun

01:12:36or another star,

01:12:38and one side can remain in the shadow.

01:12:40This is what we observe

01:12:42in the crescents of the moon.

01:12:44If your spaceship manages to get away

01:12:46from any solar system,

01:12:48you may have to say goodbye

01:12:50to the illuminated face of the ship.

01:12:52You will be very far from any star,

01:12:54and the ship will therefore fly

01:12:56in total darkness.

01:12:58But do not worry,

01:13:00our cutting-edge technologies

01:13:02The designers may place

01:13:04LED light panels similar to windows,

01:13:06and the inhabitants of the ship

01:13:08will not see much difference.

01:13:10What about people?

01:13:12A study revealed that a crew

01:13:14of 160 people could

01:13:16make up a viable population

01:13:18for about 200 years.

01:13:20The important thing is to select the crew members

01:13:22from a wide genetic pool.

01:13:24No passenger should be

01:13:26closer than cousins in the 6th or 7th degree.

01:13:28This is a projection

01:13:30of our time.

01:13:32But who knows,

01:13:34maybe hundreds of years later,

01:13:36entire countries will live

01:13:38in the same spaceship.

01:13:40Your neighbor on Earth

01:13:42will become your neighbor in space.

01:13:44It reminds me of Thor's scene

01:13:46in Ragnarok,

01:13:48where Asgardians who survived

01:13:50Aela escape with the Grandmaster's ship

01:13:52and go back to Earth to settle there.

01:13:54Maybe we'll go to Proxima Centauri B.

01:13:56It's an exoplanet,

01:13:58located beyond our solar system.

01:14:00Proxima B is located

01:14:02in another stellar system,

01:14:04and some scientists think it has potential.

01:14:06We think it is possible

01:14:08that liquid water exists on its surface.

01:14:10This is important

01:14:12because this planet is our

01:14:14closest neighbor exoplanet.

01:14:16Yes, the closest.

01:14:18But it is located 40 billion kilometers away from us.

01:14:20To better understand this proximity,

01:14:22we will give you a comparison.

01:14:24Currently,

01:14:26some of our fastest spaceships,

01:14:28namely New Horizons,

01:14:30reach a dizzying speed

01:14:32of more than 50,000 kmh.

01:14:34But even with this speed,

01:14:36it would take thousands of years to reach Proxima B.

01:14:38Let's hope we'll have found

01:14:40how to distort the space-time equation by then.

01:14:42Being realistic,

01:14:44this is the first option that seems most likely.

01:14:46Let's suppose we make the trip

01:14:48with our fastest spaceships.

01:14:50It would still be a trip

01:14:52of a few hundred years.

01:14:54But we have another minor problem.

01:14:56The lifespan of humans.

01:14:58A single crew member

01:15:00will not be able to make it to the end of the trip.

01:15:02Here, generational spaceships

01:15:04are like a solution.

01:15:06An adult community enters the ship.

01:15:08Then their children,

01:15:10and the children of their children,

01:15:12until humanity finally reaches the new planet.

01:15:14There are two other solutions.

01:15:16If researchers managed to make people live

01:15:18for centuries,

01:15:20we would not need these generational spaceships.

01:15:22Likewise,

01:15:24there could be a system to freeze people.

01:15:26It will take 20,000 people

01:15:28to start a healthy population

01:15:30on a new planet.

01:15:32For now, I want to stick to the first scenario.

01:15:34This is how we would live

01:15:36in a generational spaceship.

01:15:38Encounters would not be as romantic

01:15:40as on Earth.

01:15:42There will probably be a geneticist

01:15:44who will regulate our reproduction.

01:15:46Freedom of choice, in general, would be reduced.

01:15:48The rules will be strict.

01:15:50For each generation,

01:15:52there will be certain tasks to manage.

01:15:54Someone will have to be a doctor,

01:15:56and someone else will have to be a plumber.

01:15:58The new generations could be subjected

01:16:00to career planning tests.

01:16:02Everyone would see themselves assigned

01:16:04a profession according to their merits,

01:16:06their skills, their passions,

01:16:08and the jobs available.

01:16:10It reminds me a bit of Snowpiercer,

01:16:12but with a little luck,

01:16:14things would happen more humanly in this version.

01:16:16People all need water,

01:16:18and they will create waste.

01:16:20By then, we may no longer depend

01:16:22on plastic.

01:16:24In addition, recycling

01:16:26may be done at another level.

01:16:28However, we will need water.

01:16:30A healthy human being

01:16:32needs about 1,200 liters of water

01:16:34per year.

01:16:36It is not as if they stopped on a planet

01:16:38to fill their water tank.

01:16:40How can the inhabitants of spaceships

01:16:42solve such a problem?

01:16:44Well, there are already systems

01:16:46allowing to recycle the waste

01:16:48of astronauts in fresh water.

01:16:50The next problem is that of the infirmary.

01:16:52A spaceship can contain

01:16:54practically no bacteria or microbes,

01:16:56but people need it to strengthen

01:16:58their immune system.

01:17:00If they are too confined and land

01:17:02on a foreign planet,

01:17:04they may have a hard time dealing with

01:17:06the potential conditions that will reign there.

01:17:08Armament is also important.

01:17:10Distant space is highly radioactive.

01:17:12Our planet has a magnetic field

01:17:14that protects us from these waves

01:17:16that grill the DNA.

01:17:18Outside, the spaceship

01:17:20will need a solid shield.

01:17:22Maybe we can create

01:17:24a kind of field of force?

01:17:26NASA is working on systems

01:17:28to grow plants in space.

01:17:30We will probably see

01:17:32special sections dedicated

01:17:34to agriculture and breeding.

01:17:36I have the impression that this type of ship

01:17:38would also carry samples

01:17:40of flora and fauna.

01:17:42There may be specific parks

01:17:44and different mini-ecosystems.

01:17:46This would be excellent

01:17:48for the mental health of people on board the ship.

01:17:50It is good to preserve

01:17:52the existence of the human race,

01:17:54but existential crises

01:17:56can disturb passengers.

01:17:58They could eat their space sandwich

01:18:00in the park and relax a little

01:18:02to the sound of the birds chirping.

01:18:04Not just a garden,

01:18:06but the youngest passengers could need

01:18:08a play area and a school,

01:18:10or a cabin

01:18:12to study.

01:18:14They will probably have

01:18:16a new school program.

01:18:18How to stay alive on a foreign planet

01:18:20level CE1?

01:18:22By the time we have such a ship,

01:18:24high-tech AI and robots

01:18:26will probably be more

01:18:28in vogue than ever.

01:18:30There may be robots

01:18:32that replicate themselves.

01:18:34We can send these robots

01:18:36to our new potential planet in advance

01:18:38and see what happens.

01:18:40We can even send teams of robots

01:18:42on several planets

01:18:44and see which one has the best habitat.

01:18:46I admit it,

01:18:48generational ships look like an idea

01:18:50taken from Hollywood superproductions,

01:18:52but there is an initiative

01:18:54called the 100-Year Starship Project.

01:18:56Mark Millis,

01:18:58founder of the ToeZero Foundation,

01:19:00is one of the participants in this project.

01:19:02They designed a probe called Icarus.

01:19:04It has the theoretical ability

01:19:06to travel up to a tenth or a fifth

01:19:08of the speed of light.

01:19:10Although the current design of Icarus

01:19:12is not particularly elegant,

01:19:14since it looks like a mastodon

01:19:16the size of a skyscraper

01:19:18mainly composed of rows

01:19:20and stacks of spherical fuel tanks,

01:19:22Millis explains that it is not

01:19:24a definitive representation

01:19:26of what an interstellar ship

01:19:28could look like,

01:19:30but rather the most logical design

01:19:32at first.

01:19:34In space for humans,

01:19:36gravity is a key element

01:19:38to take into account

01:19:40to prevent the erosion

01:19:42of bone and muscle density.

01:19:44The solution is to generate gravity

01:19:46with a rotating cabin

01:19:48or centrifuge.

01:19:50But it must be large enough

01:19:52to constantly simulate

01:19:54terrestrial gravity

01:19:56to avoid disorientation

01:19:58and other health problems.

01:20:00Is there an arrival plan?

01:20:02The crew and passengers

01:20:04must be prepared

01:20:06for different scenarios.

01:20:08They must have equipment

01:20:10to scan the territory,

01:20:12even self-defense weapons

01:20:14to protect themselves

01:20:16from potentially hostile life forms.

01:20:18Once they have arrived

01:20:20at Bonport,

01:20:22they will also need tools

01:20:24to build their new home

01:20:26when they finally arrive

01:20:28on their new planet.

01:20:30Hi mom,

01:20:32I brought you a stone

01:20:34in memory of the surface of Mars.

01:20:36New professions could appear

01:20:38as a space travel guide live

01:20:40and we could need

01:20:42a type of document,

01:20:44like a visa,

01:20:46to visit other habitable planets.

01:20:48A meteor shower is expected,

01:20:50so stay in your base

01:20:52for the next two years,

01:20:54says the TV news presenter.

01:20:56Okay, okay, I'll calm down.

01:20:58So, how would you imagine

01:21:00a ship capable of transporting

01:21:02humans from one solar system to another?

01:21:04Would it have wings

01:21:06or would it look like a rocket?

01:21:08Tell us more about the look

01:21:10that comes to your mind.

01:21:12The protective shield of our planet

01:21:14is deteriorating

01:21:16and ends up not being enough.

01:21:18The same goes for our satellites.

01:21:20First, high-orbit communication satellites

01:21:22land on Earth.

01:21:24Then, low-Earth-orbit astronauts

01:21:26land on Earth.

01:21:28And finally,

01:21:30dangerous and relentless cosmic rays

01:21:32begin to bombard the entire planet,

01:21:34causing chaos and devastation.

01:21:36Are these the terrifying consequences

01:21:38of the reversal of the magnetic field

01:21:40of the planet that we will have to face?

01:21:42At the moment,

01:21:44while you are watching this video,

01:21:46the magnetic pole north of the Earth

01:21:48is extremely unbalanced.

01:21:50It is so serious that scientists

01:21:52will have to revise the global model

01:21:54Does this mean that the magnetic pole

01:21:56of our planet will soon reverse?

01:21:58A little patience.

01:22:00We will discover it a little later.

01:22:02You see, the magnetic pole moves

01:22:04quite erratically from the Canadian Arctic

01:22:06to Siberia.

01:22:08And these movements are very unpredictable.

01:22:10But it is normal for the pole to move.

01:22:12There are long-term findings

01:22:14in London and Paris

01:22:16that prove that the magnetic pole north

01:22:18moves randomly around the rotation pole

01:22:20over periods of several hundred years.

01:22:24But the most surprising thing

01:22:26in its movement

01:22:28is that it tends to gain in speed.

01:22:30Towards the middle of the 90s,

01:22:32the magnetic pole has inopinement

01:22:34accelerated,

01:22:36going from a little over 14 km

01:22:38to 54 km per year.

01:22:40And recently, the pole has crossed

01:22:42the date line, heading

01:22:44towards the eastern hemisphere.

01:22:46The European Space Agency

01:22:48launched satellites

01:22:50to analyze the magnetic field in 2013.

01:22:52Thanks to them, researchers have

01:22:54precious data that they can not only

01:22:56use to draw up maps of the magnetic field,

01:22:58but also to update them

01:23:00every 6 to 12 months.

01:23:02This is how they were able to notice

01:23:04that the main field was shrinking, too.

01:23:06This could be a sign that the magnetic field

01:23:08of the planet is about to reverse.

01:23:10To better understand this process,

01:23:12we must understand how the field

01:23:14emanating from our nucleus works.

01:23:16Let's say we have a magnetized bar

01:23:18that crosses the center of our planet

01:23:20between a north and a south pole.

01:23:22This magnet is incredibly powerful,

01:23:24representing about 75%

01:23:26of the intensity of the magnetic field

01:23:28of our planet on the surface.

01:23:30Our magnet does not only move,

01:23:32but it also weakens

01:23:34by about 7% every century.

01:23:38It must be admitted that this magnet

01:23:40is not a perfect representation

01:23:42of the field produced by our nucleus.

01:23:44It is rather as if electric currents

01:23:46generated the magnetic field of the Earth.

01:23:48This facilitates the understanding

01:23:50of what is happening to our planet right now.

01:23:52The magnetic field of our planet

01:23:54plays an important role in the protection

01:23:56against dangerous radiations

01:23:58and geomagnetic activity,

01:24:00which is the product of the interaction

01:24:02between the solar wind

01:24:04and the Earth's magnetosphere.

01:24:06The magnetic field of the Earth

01:24:08also moves.

01:24:10Scientists have studied and followed

01:24:12the movement of magnetic poles

01:24:14over hundreds of years.

01:24:16They have also studied

01:24:18the global geometry of the magnetic field

01:24:20of our planet.

01:24:22And they can also indicate

01:24:24the beginning of the field inversion.

01:24:26This is what is called a shift

01:24:28between the north and south magnetic poles.

01:24:30You should know that if the north magnetic pole

01:24:32moves a little,

01:24:34it is not a very big problem.

01:24:36But a complete reversal

01:24:38could have a serious impact

01:24:40on the climate of our planet

01:24:42as well as on our modern technologies.

01:24:44Unfortunately, this does not happen overnight.

01:24:46The whole process

01:24:48extends over thousands of years.

01:24:50In addition, even if the magnetic pole

01:24:52weakens during a pole inversion,

01:24:54it does not disappear completely.

01:24:56Thus, the terrible events

01:24:58at the beginning of this video

01:25:00are unlikely to happen to us.

01:25:02The magnetosphere will continue

01:25:04to protect the planet from cosmic rays

01:25:06and charged solar particles,

01:25:08even if a certain amount

01:25:10of particular radiation

01:25:12The magnetic fields are generated

01:25:14by electric charges in motion.

01:25:16If a material allows its charges

01:25:18to move easily in it,

01:25:20it is called a conductor.

01:25:22Metal is an excellent conductor

01:25:24and we often use it to transfer

01:25:26electric currents from one place to another.

01:25:28In this case, the electric current

01:25:30is made up of negative charges

01:25:32called electrons moving through metal.

01:25:34It is this current that generates

01:25:36a magnetic field.

01:25:38The Earth has a liquid iron core.

01:25:40In other words, there are layers

01:25:42and layers of conductive materials

01:25:44inside our planet.

01:25:46Charging currents constantly move

01:25:48through the core and liquid metal

01:25:50also circulates there, generating

01:25:52the magnetic field.

01:25:56This magnetic field produces

01:25:58something that looks like a bubble

01:26:00around the planet.

01:26:02It is called the magnetosphere

01:26:04and it is located above the highest part

01:26:06of the atmosphere.

01:26:08The magnetosphere protects

01:26:10and deflects high-energy cosmic radiation

01:26:12that would otherwise be extremely dangerous

01:26:14for people and other forms of life on Earth.

01:26:16The magnetosphere also interacts

01:26:18with the ionosphere,

01:26:20the layer of the atmosphere of our planet

01:26:22which contains tons of ions and free electrons

01:26:24and which is able to reflect radio waves.

01:26:26The interaction between these two layers

01:26:28and the magnetized solar wind

01:26:30is what scientists call

01:26:32the space weather.

01:26:34The solar wind is normally quite light

01:26:36and there is absolutely no space weather.

01:26:38But sometimes,

01:26:40the sun begins to eject

01:26:42huge clouds of magnetized gas

01:26:44that can reach incredible speeds.

01:26:46They are called coronal mass ejections

01:26:48or EMC.

01:26:50These are ejected from the sun for several hours.

01:26:52EMCs are generally

01:26:54related to huge twisted filaments

01:26:56and can occur spontaneously.

01:26:58Their frequency varies according to a solar cycle of 11 years.

01:27:00For example, at the minimum solar,

01:27:02we can observe an ejection per day.

01:27:04And when the sun is in its most active phase,

01:27:06there can be up to 3 EMCs per day.

01:27:08Coronal mass ejections

01:27:10disturb the calm flow of the solar wind

01:27:12and cause serious disturbances

01:27:14capable of damaging things

01:27:16both in the space near the Earth,

01:27:18like satellites,

01:27:20and on the surface of the planet.

01:27:22If coronal mass ejections

01:27:24reach the Earth,

01:27:26their interaction with the magnetosphere

01:27:28generates geomagnetic storms.

01:27:30These can produce auroras

01:27:32when a flow of charged particles

01:27:34hits the atmosphere and illuminates it.

01:27:36And then there are also solar eruptions.

01:27:38They develop faster

01:27:40and with much more energy

01:27:42than coronal mass ejections.

01:27:44Solar eruptions often occur

01:27:46shortly after coronal mass ejections.

01:27:48Solar eruptions often occur

01:27:50shortly after coronal mass ejections.

01:27:52The most powerful volcanic eruptions

01:27:54do not occur

01:27:56compared to solar eruptions

01:27:58which release 10 million times more energy.

01:28:00In a few minutes,

01:28:02a solar eruption can emit

01:28:04billions of tons of charged particles.

01:28:06Solar eruptions are also incredibly hot,

01:28:08with temperatures reaching

01:28:10several million degrees.

01:28:14Astronomers think that such solar explosions

01:28:16occur when the magnetic field

01:28:18of the Sun

01:28:20twists in certain regions.

01:28:22At some point,

01:28:24all the stored energy is released.

01:28:26The star emits light and particles,

01:28:28mostly electrons and protons.

01:28:30Most solar eruptions last a few minutes,

01:28:32but some continue for hours.

01:28:34A powerful solar storm

01:28:36can potentially cause

01:28:38a devastating power outage

01:28:40on the entire Earth.

01:28:42If it were not for the Earth's magnetosphere,

01:28:44the effects of solar activity

01:28:46would be much more devastating.

01:28:48Fortunately, it deflects most of the solar particles

01:28:50that rush to our planet from our star

01:28:52at a speed of more than 1,600,000 km per hour.

01:28:54at a speed of more than 1,600,000 km per hour.

01:28:56Even so, during space weather events,

01:28:58there is a lot of dangerous radiation

01:29:00near the Earth.

01:29:02It can potentially harm astronauts

01:29:04and spacecraft.

01:29:06In addition, the space weather can damage

01:29:08our major driving systems,

01:29:10such as pipelines and electrical networks.

01:29:12For example, by overloading the currents

01:29:14circulating inside.

01:29:16Scientists map

01:29:18and regularly follow the orientation

01:29:20and global shape of the magnetic field

01:29:22of our planet.

01:29:24They use local measurements

01:29:26of the orientation and amplitude of the field.

01:29:28This is how they were able to conclude

01:29:30that the location of the North Magnetic Pole

01:29:32had moved almost 1,000 km

01:29:34since the first measurements

01:29:36were taken in 1831.

01:29:38The magnetic field of our planet

01:29:40reverses on a time scale

01:29:42ranging from 100,000 to 1,000,000 years.

01:29:44We can say

01:29:46how often this happens

01:29:48by looking at the volcanic rocks

01:29:50at the bottom of the ocean.

01:29:52These rocks maintain the orientation

01:29:54and force of the Earth's magnetic field

01:29:56at the time of their creation.

01:29:58Thus, the dating of these rocks

01:30:00gives us an image of the evolution

01:30:02of the magnetic field of our planet

01:30:04over time.

01:30:06From a geological point of view,

01:30:08field inversions occur quite quickly.

01:30:10But they are extremely slow

01:30:12from a human point of view.

01:30:14A complete reversal

01:30:16normally takes a few thousand years.

01:30:18But during this period,

01:30:20the orientation of the magnetosphere

01:30:22can change, exposing the Earth

01:30:24to more cosmic radiation.

01:30:26Such events tend to modify

01:30:28the concentration of ozone in the atmosphere.

01:30:30In any case,

01:30:32scientists cannot say with certainty

01:30:34when the next magnetic field

01:30:36reversal will take place.

01:30:38But they continue to map

01:30:40and track the movement of the North Magnetic Pole

01:30:42of our planet.

01:30:44In fact, the Earth is not the only planet

01:30:46with a magnetic field.

01:30:48Jupiter also has a layer of conductive

01:30:50metallic hydrogen that generates

01:30:52their magnetic field.

01:30:54Jupiter's internal field prevents

01:30:56the solar wind from interacting directly

01:30:58with the atmosphere of the planet.

01:31:02If an asteroid like Apophis

01:31:04hit the Earth,

01:31:06we would be destroyed.

01:31:08Immense earthquakes

01:31:10shook the Earth

01:31:12and tsunamis flooded everything.

01:31:14Apophis, a celestial body

01:31:16with a history of several billion years,

01:31:18has been present in the solar system

01:31:20since its creation.

01:31:22You are probably wondering

01:31:24what is the probability

01:31:26that this gigantic stone

01:31:28will collide with our planet

01:31:30in 2029?

01:31:32Well, we'll see that, okay?

01:31:34Apophis is a huge asteroid

01:31:36discovered in 2004

01:31:38by the National Kitt Peak Observatory

01:31:40in Arizona.

01:31:42Since then, it has been said

01:31:44that it is the most dangerous asteroid

01:31:46ever located.

01:31:48It is about 330 meters wide.

01:31:50It is a little bigger

01:31:52than the Empire State Building

01:31:54or the Eiffel Tower.

01:31:56It is because it is so scary

01:31:58that it was named Apophis,

01:32:00after the Egyptian immortal creature

01:32:02that brought eternal darkness

01:32:04and destruction.

01:32:06In 2021, researchers had the

01:32:08exceptional opportunity

01:32:10to study this floating rock

01:32:12that we will come back to in a minute.

01:32:14Some scientists say

01:32:16that there is a 2.7% chance

01:32:18that Apophis will hit Earth

01:32:20on Friday, April 13, 2029.

01:32:24It would be the Yarkovsky effect

01:32:26that would be at stake

01:32:28because it would push this big

01:32:30space rock to Earth.

01:32:32This effect comes from the unequal emission

01:32:34of thermal photons,

01:32:36whose result is an unimaginable force

01:32:38exerted on the affected object.

01:32:40These photons exert

01:32:42an immense thrust

01:32:44and play an essential role

01:32:46in the dynamics of the body in question.

01:32:48The asteroid has two faces,

01:32:50a dark one and a light one,

01:32:52just like the moon.

01:32:54The light side is facing the sun

01:32:56and is warmer than the dark side.

01:32:58But the object rotates itself

01:33:00so that its faces constantly change

01:33:02direction and temperature.

01:33:04These changes are not good

01:33:06because they push Apophis slightly

01:33:08No one knows how the Yarkovsky effect

01:33:10will influence the trajectory of the asteroid.

01:33:12On the other hand,

01:33:14during the last passage of the asteroid

01:33:16near Earth in 2021,

01:33:18astronomers used radars

01:33:20to take precise measurements

01:33:22of its trajectory

01:33:24and they were able to conclude

01:33:26that Apophis will pass at about

01:33:2832000 km from Earth in 2029

01:33:30and will not disturb us for at least 100 years.

01:33:34In general, every 8000 years,

01:33:36our planet is affected

01:33:38by a shooting star of dimensions

01:33:40similar to that of Apophis.

01:33:42The last time we were hit

01:33:44by a slightly smaller meteor,

01:33:46it was in 2013.

01:33:50A new space machine

01:33:52developed by NASA,

01:33:54called OSIRIS-REx,

01:33:56was launched in 2016

01:33:58to collect samples

01:34:00on another slightly less terrifying celestial body,

01:34:02Bennu.

01:34:04The object was targeted,

01:34:06took some samples,

01:34:08quickly said goodbye to Bennu

01:34:10and returned to Earth.

01:34:12The samples were safely stored

01:34:14in a capsule deposited in Utah.

01:34:16So far,

01:34:18this is the most significant sample

01:34:20ever taken on an asteroid.

01:34:22After its delivery,

01:34:24the ship did not waste time

01:34:26and went after Apophis.

01:34:28For this mission,

01:34:30OSIRIS-REx was renamed OSIRIS-APEX

01:34:32after Apophis.

01:34:34With a little luck,

01:34:36on April 2, 2029,

01:34:38when the asteroid passes near Earth,

01:34:40the space probe will reach Apophis

01:34:42to land there.

01:34:44It will stay on it for 18 months,

01:34:46collecting precious information

01:34:48and taking thousands of photos.

01:34:52The asteroid will be monitored

01:34:54with powerful telescopes.

01:34:56At some point,

01:34:58Apophis will be too close to the sun

01:35:00so OSIRIS-APEX will take care

01:35:02of monitoring it.

01:35:04If you live in Europe,

01:35:06West Asia or Africa,

01:35:08you are one of the lucky ones

01:35:10who will have the unique opportunity

01:35:12in a lifetime to see Apophis

01:35:14with the naked eye.

01:35:16It will be visible in the sky

01:35:18of these regions in 2029

01:35:20and those who have telescopes

01:35:22will be able to see it again in 2036.

01:35:24OSIRIS-APEX will certainly

01:35:26encounter some problems

01:35:28because the asteroid has a thick crust

01:35:30and the spacecraft will not be able

01:35:32to collect data as easily

01:35:34as on Bennu.

01:35:36OSIRIS-APEX has a single propeller

01:35:38that will blow all the dust of Apophis

01:35:40when it lands.

01:35:42It will be a perfect opportunity

01:35:44to analyze the asteroid's surface

01:35:46and see what it is made of.

01:35:48The probe will spend a year and a half

01:35:50mapping the asteroid

01:35:52trying to detect changes in its shape.

01:35:54All these researches will show

01:35:56how the asteroid moves

01:35:58and we will have a better idea

01:36:00of how to protect our planet

01:36:02from such objects.

01:36:04In 2025, NASA will also launch

01:36:06the Apophis Pathfinder mission

01:36:08and it will be the first spacecraft

01:36:10to ever touch this asteroid.

01:36:12It will land about a year

01:36:14after its launch.

01:36:16In addition, NASA has proposed

01:36:18to send a draft of small machines

01:36:20to allow humanity to develop

01:36:22effective protection tactics

01:36:24We know that Apophis comes from

01:36:26the main asteroid belt

01:36:28located between Mars and Jupiter.

01:36:30Over the last million years,

01:36:32this celestial body has changed its trajectory

01:36:34due to the considerable influence

01:36:36of Jupiter's gravity.

01:36:38Now, it seems to favor the sun more,

01:36:40which means that this asteroid

01:36:42is very close to Earth.

01:36:44This is why it is classified

01:36:46among the celestial bodies

01:36:48neighboring our planet.

01:36:50Many tests have been carried out

01:36:52Among the solutions,

01:36:54there is drilling and detonation

01:36:56of the interior space body,

01:36:58but new technologies are also being tested,

01:37:00such as attaching rockets

01:37:02to redirect the harmful object

01:37:04away from Earth.

01:37:06We could also hit it

01:37:08with a sufficiently powerful force

01:37:10to change its direction.

01:37:12Apophis is an asteroid of type S

01:37:14composed of rocks and metals,

01:37:16iron, nickel, etc.,

01:37:18and that looks like a peanut.

01:37:20The samples collected can reveal

01:37:22how life on Earth began

01:37:24and how plants appeared.

01:37:26Many theories suggest

01:37:28that water came to our planet

01:37:30thanks to an asteroid or a comet.

01:37:32Asteroids are like

01:37:34precious time capsules.

01:37:36Unlike terrestrial rocks,

01:37:38which have undergone countless changes,

01:37:40such as erosion,

01:37:42most celestial bodies are intact

01:37:44and much easier to study.

01:37:46When meteors fall on Earth,

01:37:48they create impenetrable debris.

01:37:50That is why it is so important

01:37:52to study Apophis right now.

01:37:54In addition,

01:37:56some asteroids are made of precious metals,

01:37:58such as platinum.

01:38:00At the moment, we have a strong demand

01:38:02for metals intended for industry,

01:38:04and mining on Earth

01:38:06is quite difficult.

01:38:08A single big meteor could provide us

01:38:10with iron, nickel, gold and platinum

01:38:12for millions of years.

01:38:14If Apophis contains all these metals,

01:38:16we will have to decompose it

01:38:18and bring it back to Earth.

01:38:20A single asteroid could cost billions of dollars.

01:38:22Space mining

01:38:24would then be extremely profitable.

01:38:26However, it would cost us

01:38:28more to bring it back to Earth

01:38:30than to extract its materials here.

01:38:32With the technological progress

01:38:34and the development of new types of rockets,

01:38:36it may be possible

01:38:38one day.

01:38:40So,

01:38:42even if we have nothing to fear

01:38:44about Apophis

01:38:46for another hundred years,

01:38:48we still need to know

01:38:50what would happen

01:38:52if such an impact occurred.

01:38:54Come on, admit it,

01:38:56you want to know.

01:38:58Well, let me tell you

01:39:00that you would hear a huge noise

01:39:02and that you would know

01:39:04that a disaster has even reached

01:39:06kilometers away.

01:39:08You would have to leave your home immediately.

01:39:10Shortly after the impact,

01:39:12it would probably be the best thing to do.

01:39:14But you should not run away

01:39:16by car.

01:39:18There would be huge traffic jams

01:39:20and everyone would panic.

01:39:22Moving by foot or by bike

01:39:24would be your best option in this scenario.

01:39:26A preferred means of transport

01:39:28would be the plane.

01:39:30So, if you have always dreamed

01:39:32of obtaining your pilot's license,

01:39:34you now have a good excuse.

01:39:36You would also have to take

01:39:38enough to eat and drink

01:39:40near the ocean or the sea

01:39:42is pleasant.

01:39:44But in this scenario,

01:39:46there would not be a worse place.

01:39:48Huge waves would indeed hit the coast

01:39:50after the impact.

01:39:52Far from the impact area,

01:39:54tsunamis could take up to 30 hours

01:39:56to arrive.

01:39:58It would give you a little time

01:40:00to prepare.

01:40:02If one of the many possible

01:40:04apocalyptic scenarios comes true

01:40:06and humanity is eradicated,

01:40:08a black box will tell

01:40:10those who will come after what led us

01:40:12to our end.

01:40:14This strong 10-meter-long chamber

01:40:16located in a region

01:40:18far from the west of Tasmania

01:40:20is supposed to document all the mistakes

01:40:22that humanity has made

01:40:24and which have caused the apocalypse.

01:40:26Artists, architects and researchers

01:40:28at the origin of the black box on earth

01:40:30think that this reinforced steel

01:40:32installation will resist fire,

01:40:34water and all other natural disasters.

01:40:38Unless, of course, the planet is

01:40:40completely destroyed.

01:40:42Just like the black boxes

01:40:44found in airplanes.

01:40:46This time capsule is supposed to

01:40:48help the civilization that will follow

01:40:50ours to avoid the tragic fate

01:40:52of our humanity.

01:40:54The project is entirely

01:40:56non-commercial and carries

01:40:58an important message.

01:41:00The box will be filled with storage disks

01:41:02and will be connected to the Internet.

01:41:04Solar panels on the roof

01:41:06will supply electricity

01:41:08and batteries will ensure the storage

01:41:10of emergency energy.

01:41:12Every time the sun shines in the sky,

01:41:14the black box will update its scientific data.

01:41:16An algorithm will sort these data

01:41:18in order to save only the relevant

01:41:20information for the project.

01:41:22We will measure the terrestrial and marine

01:41:24temperatures, the acidification of the oceans,

01:41:26the extinction of species,

01:41:28the use of land as well as

01:41:30human demography and energy consumption.

01:41:32Among the secondary data,

01:41:34we will find newspaper titles,

01:41:36social network posts and news

01:41:38on the main events

01:41:40concerning the environment.

01:41:44The creators of the box decided to code

01:41:46and store their data in different formats,

01:41:48including binary code.

01:41:52Instructions on how to retrieve

01:41:54all this precious information

01:41:56will be engraved on the outside of the box.

01:42:00Some of the biggest brains working on this project

01:42:02fear that this could make some

01:42:04curious people want to force the box

01:42:06long before it's time to do it.

01:42:08The hard disk powered by solar energy

01:42:10will have enough space

01:42:12to collect data for 50 years.

01:42:16The most pessimistic scientific models

01:42:18do not predict the end of the world

01:42:20before this date.

01:42:22This great misfortune may not even happen

01:42:24in centuries.

01:42:26The idea of a box that records

01:42:28everything that happens before an

01:42:30accident is born in the middle of the 20th century.

01:42:34At that time,

01:42:36the world's first jet,

01:42:38the The Avalanche Comet,

01:42:40crashed seven times in two years,

01:42:42killing 110 people.

01:42:46The Australian Civil Aviation Department

01:42:48wanted to know what caused

01:42:50these accidents.

01:42:52Among the experts,

01:42:54there was Dr. David Warren,

01:42:56a chemist specializing in fuels.

01:42:58He realized

01:43:00that we simply did not have enough data

01:43:02to draw conclusions.

01:43:04There was no one to tell

01:43:06what happened before the accident.

01:43:08He remembered seeing a dictaphone

01:43:10recording sound on a steel wire

01:43:12at a commercial fair.

01:43:14So, he wrote to his superior

01:43:16to offer him to design

01:43:18a voice recorder that would follow

01:43:20what was happening in the cockpit.

01:43:22Flight data would also be recorded

01:43:24and stored in an unbreakable box.

01:43:26Aviation was not very important

01:43:28in Australia at that time,

01:43:30so the idea did not interest

01:43:32the superior in question.

01:43:34But Warren still began

01:43:36to work on a prototype in his garage.

01:43:40He showed his device

01:43:42to the secretary of the British Air Registration Board

01:43:44passing through Australia,

01:43:46and he loved the idea.

01:43:48Soon, Dr. Warren was able to

01:43:50form a whole team to help him

01:43:52develop a pre-production prototype.

01:43:54His invention

01:43:56does not actually have the name

01:43:58of a black box,

01:44:00but of a flight recorder,

01:44:02and it is orange, not black.

01:44:04We probably say that it is black

01:44:06because it takes this color

01:44:08after an accident.

01:44:10Or maybe because the first boxes

01:44:12were painted like that

01:44:14to avoid solar reflection.

01:44:16Or because it is the name

01:44:18that scientists give to devices

01:44:20with input and output of data

01:44:22in the context.

01:44:24So, the flight recorder

01:44:26consists of two parts.

01:44:28A data recorder

01:44:30and a vocal recorder.

01:44:32Historically, it was two boxes,

01:44:34but now it is two cylinders.

01:44:36The data recorder

01:44:38retains the flight parameters.

01:44:40Exhaust gases, temperature,

01:44:42fuel flow, speed,

01:44:44altitude and descent rate.

01:44:46The second cylinder records

01:44:48the sounds in the cockpit

01:44:50and communicates with the air control

01:44:52in case of an accident.

01:44:54The device records only for two hours

01:44:56and then erases these data.

01:45:00Sometimes the two parts are combined

01:45:02and it looks like a box.

01:45:06The box records the data

01:45:08and sees them in the cockpit.

01:45:10But it is actually placed

01:45:12at the back of the plane

01:45:14where the structure of the device

01:45:16will protect them in case of an accident.

01:45:18It is a locating beacon

01:45:20that is activated by contact with water.

01:45:22It emits a signal for 30 days.

01:45:24The bright orange color of the recorder

01:45:26allows the search teams

01:45:28to locate it more easily.

01:45:30Sometimes it takes a lot of time

01:45:32to find a box.

01:45:34And in some cases,

01:45:36it is never found.

01:45:38Long before the invention of the first plane,

01:45:40there was a black box

01:45:42whose range was universal.

01:45:44The old library of Alexandria.

01:45:46In Antiquity, people in Egypt,

01:45:48Mesopotamia and Greece

01:45:50were relatives of libraries and archives.

01:45:54But these first institutions

01:45:56were mainly intended to preserve

01:45:58traditions and heritage.

01:46:00The very concept of a universal library

01:46:02only became a reality

01:46:04when the Greeks began to think big.

01:46:06They were so impressed

01:46:08by what their neighbors were doing in Egypt

01:46:10that they organized expeditions

01:46:12to acquire knowledge.

01:46:14Alexander the Great, king of Macedonia,

01:46:16seeing this new thirst for knowledge,

01:46:18demanded of his companions,

01:46:20generals and scholars,

01:46:22to bring him everything he could learn

01:46:24about the regions that had not yet been explored.

01:46:26This allowed him to collect

01:46:28a lot of information on geography

01:46:30and contributed to the creation

01:46:32of a huge library.

01:46:34Most of the information was written in Greek.

01:46:36For example,

01:46:38Aristotle's writings were found in the corpus of literature.

01:46:40According to some sources,

01:46:42during this search for books,

01:46:44the founders of the library

01:46:46arrested all the ships

01:46:48entering the port of Alexandria.

01:46:50If they found books,

01:46:52they took them to the library.

01:46:54If they decided that a book was precious,

01:46:56they made a copy of it

01:46:58and gave it to its owner

01:47:00with a compensation.

01:47:02The original remained at the library.

01:47:04Another story tells us that

01:47:06Ptolemy III, grandson of the founder

01:47:08of the library,

01:47:10offered the governors of Athens

01:47:12a huge compensation for the right

01:47:14to copy the texts of the greatest poets.

01:47:16He kept the originals

01:47:18and sent them copies.

01:47:20It was the Roman Empire

01:47:22that, having accessed domination,

01:47:24burned all its knowledge

01:47:26without thinking that it would lead them

01:47:28to their own loss.

01:47:30There was then no way

01:47:32to disseminate the information.

01:47:34A single source held most of the knowledge

01:47:36The great minds were not content

01:47:38to fill it.

01:47:40They also created important correspondence

01:47:42between the works,

01:47:44taking the best part of the library.

01:47:46If the library of Alexandria

01:47:48had not burned,

01:47:50we would have today

01:47:52invaluable knowledge

01:47:54about the people who lived at that time.

01:47:56Some scientists think that this knowledge

01:47:58could have saved the Vikings

01:48:00who settled in Greenland

01:48:02several centuries ago.

01:48:04It would have helped the population

01:48:06of Easter Island to identify

01:48:08and solve the problems

01:48:10caused by volcanic activity,

01:48:12latitude and precipitation,

01:48:14and to restore soil fertility.

01:48:16It is said that a person living

01:48:18at our time is exposed

01:48:20in one day to as much data

01:48:22as a person of the 15th century

01:48:24throughout his life.

01:48:26And there is a theory

01:48:28according to which all the papers

01:48:30of the library of Alexandria

01:48:32are stored on a single USB key.

01:48:36So much data is generated

01:48:38every day that it could

01:48:40become harmful.

01:48:42We are then talking about an overload

01:48:44of information.

01:48:46We are heading towards

01:48:48a global civilization.

01:48:50So if all this knowledge disappeared,

01:48:52we would lose not an empire,

01:48:54but the whole world.

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