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Transcript

00:00:00 If you want to travel in space, prepare to spend about 55 million dollars.

00:00:07 But in the near future, you will probably be able to travel in space by simply pressing a button without ruining yourself.

00:00:14 Because space elevators could be a good option.

00:00:17 While the idea of a galactic elevator seems to come from a science fiction movie,

00:00:22 it is a real possibility that could revolutionize space travel.

00:00:26 With an estimated cost of 8 billion dollars, such an elevator could only represent a single investment that would last us forever.

00:00:35 NASA alone spends about 2.7 million dollars on rocket fuel every minute of flight.

00:00:44 To launch a rocket, they must spend up to 178 million dollars.

00:00:50 These costs could be considerably reduced if we used elevators.

00:00:55 Most of the tallest buildings on Earth have massive foundations to help balance their weight.

00:01:01 The more you look up in the air, the more they get smaller.

00:01:04 Even the highest skyscraper in the world, Burj Khalifa, is thick at its base and thin at its top.

00:01:11 If we wanted to build something that looks like a gigantic elevator,

00:01:15 we would need a huge amount of concrete to build the foundations.

00:01:20 This goes against our original goal of saving money.

00:01:25 Now, take a string, attach a ball to its end and start spinning it.

00:01:31 The string in your hand will stay in place and the ball will spin around your hand.

00:01:36 This is what is called centrifugal force.

00:01:38 And the elevator will work the same way.

00:01:40 The ball will be a base in space and the rope will pull it to the ground.

00:01:47 The station we will enter through the elevator would be in the middle of the Atlantic Ocean

00:01:52 and the rope would extend from there.

00:01:55 To make this possible, it must be perfectly synchronized with the rotation of the Earth.

00:02:01 Otherwise, it will simply break or roll around the Earth like a whip.

00:02:06 In addition, the orbit followed by the rope should form a perfect circle

00:02:11 because the line could neither shorten nor extend.

00:02:14 Many calculations have been made to find the ideal solution.

00:02:18 Wait a minute.

00:02:19 This is what algebra is for.

00:02:21 Who would have thought?

00:02:23 In the meantime, we will not bore you with more math.

00:02:27 Let's address directly the precise distance between the Atlantic Station

00:02:31 and the one in space, which must be 36,000 km above the Earth,

00:02:36 where the geosynchronous orbit begins.

00:02:39 There, the four ascending forces are much stronger than the only descending force.

00:02:46 This is why the station would remain in place.

00:02:49 When you build a house or a building, you start from the bottom and progress up.

00:02:55 But to create this marvel of engineering,

00:02:57 we would need to take it the other way around and start from the top.

00:03:02 The main problem here would be the weight.

00:03:06 If the line was too heavy, it would disrupt the orbit,

00:03:09 and the load-bearing mount would not work.

00:03:12 We would therefore need to balance the space station to ensure a flawless operation.

00:03:20 Steel is one of the most robust materials on Earth.

00:03:24 The cable of each elevator is made of steel.

00:03:27 But when you need a 36,000 km long cable, things can get a little complicated.

00:03:34 Steel is difficult to break, but it is bulky.

00:03:37 And when you have to use a lot of it, that's when problems start to arise.

00:03:43 We use a lot of steel in construction,

00:03:46 but we have lighter materials at our disposal

00:03:49 that could exert less strain on the station and eliminate this problem.

00:03:54 In addition, the cable should be wired,

00:03:56 because at the end the constraint would be practically non-existent.

00:04:00 But it should always be thicker than necessary, due to many safety factors.

00:04:06 At first, the cable would be barely more than 1 mm thick.

00:04:10 After a lot of complicated calculations,

00:04:12 we can determine its size at the end of the race,

00:04:15 which is such a long number that we would be unable to pronounce it.

00:04:19 But believe us, it is a very, very large number.

00:04:23 So steel is out of the question.

00:04:25 Another candidate is Kevlar, which is five times more resistant than steel.

00:04:29 And if we added materials such as carbon and titanium to this alloy,

00:04:33 its resistance would still be doubled.

00:04:36 The cable would then have a diameter between 80 and 170 meters.

00:04:40 It is much smaller than what could be the diameter of a similar steel cable.

00:04:45 The bad news is that it would cost way too much.

00:04:49 So if we do not find the ideal material to build this cable,

00:04:53 the very idea of a space elevator will never be a vast waste of time.

00:04:58 If only we had a light, miraculous material at hand,

00:05:05 capable of taking a pressure of 60 gigapascals,

00:05:09 and which would also have a conicity ratio of 1.6.

00:05:13 Oh, but wait, we do have such a material.

00:05:17 It is what we call carbon nanotubes.

00:05:20 They have a resistance of 130 gigapascals,

00:05:23 which is much more than what we need.

00:05:27 Nanotubes are made from carbon,

00:05:29 and are 100,000 times thinner than human hair.

00:05:32 This material is solid and has a good conductivity,

00:05:36 which is made possible by its unique atomic structure.

00:05:40 We use this innovation in many things,

00:05:43 from batteries to optics,

00:05:45 and they can be completely modified and adapted to many other uses.

00:05:50 Bradley Edwards is the man responsible for this idea.

00:05:53 NASA was looking for new innovations and told him,

00:05:57 "Do not try anything too crazy and just start building a space shuttle."

00:06:01 We suppose that Bradley had to take this as a challenge,

00:06:04 because he started working on the elevator.

00:06:06 Edwards therefore wrote an article on a galactic transporter.

00:06:10 When he published it,

00:06:12 he expected that many experts would wash the flaws in his work.

00:06:16 But surprisingly, no one did.

00:06:19 His concept was irreproachable.

00:06:21 He had the idea of attaching a line of nanotubes to a rocket

00:06:25 and propelling it into space.

00:06:28 The other end of the cable would fall back to Earth,

00:06:31 and robots would use it to climb and extend it

00:06:34 so that we could start building a space station.

00:06:38 After that, the elevator could start to run everything and anything,

00:06:42 from solar panels to tourists.

00:06:45 In the future, space tourism could become accessible.

00:06:48 Who knows, we could even go on vacation in space one day.

00:06:52 Hey! Are you looking for an escape atmosphere?

00:06:55 Well, don't come here, we don't have any.

00:06:58 Oops, probably not the best advertising slogan, is it?

00:07:02 A few years ago, we could only create microscopic carbon nanotubes.

00:07:07 But over time, more research has been done to make them bigger.

00:07:12 Today, they reach a few centimeters.

00:07:15 In 20 years, they could be several kilometers long.

00:07:19 Carbon costs $1 a gram.

00:07:22 If we did the math, we would see that it would take us about $1 billion to build this elevator.

00:07:27 Yes, it seems expensive, but it is a long-term solution for space travel,

00:07:32 which could save us a lot of money.

00:07:35 Everything looks perfect on paper.

00:07:38 But the main reason why NASA chose not to pursue this project

00:07:42 is that at the moment, there are probably more than 128 million debris floating in the Earth's orbit.

00:07:48 And it could pose a real threat to this elevator.

00:07:52 It could, of course, be designed to resist a few impacts from time to time.

00:07:58 But being constantly bombed was not part of the equation.

00:08:01 Nevertheless, Bradley supports that a fleet of surveillance devices detects these spatial debris.

00:08:06 Thus, the elevator could be able to avoid them all.

00:08:11 If something hit the elevator, or if the cable broke in one way or another,

00:08:17 the consequences would not be so severe.

00:08:20 Finally, if there were no passengers on board, of course.

00:08:24 If the line was cut, the elevator would simply drift into space

00:08:28 and would not pose any threat to anyone.

00:08:31 In Japan, engineers are trying to build a space elevator.

00:08:35 This one could also be used for mining in space.

00:08:41 We could easily cover the cost of this elevator by catching asteroids on the way,

00:08:46 because some of them are made of precious metals.

00:08:49 We could then exploit them and quickly repatriate them to Earth.

00:08:53 Imagine a place where a single day lasts longer than a whole year.

00:08:59 On Venus, a day, that is to say a complete rotation on its axis,

00:09:03 is as long as 243 days on Earth.

00:09:06 And what is even stranger, despite the fact that Venus knows one day without end,

00:09:11 is that its year is shorter than that of Earth.

00:09:14 While Earth takes about 365 days to make a complete orbit around the Sun,

00:09:19 Venus does it in only 225 days.

00:09:22 So, in a way, for Venus, a day is more significant than a whole year.

00:09:28 Venus is a strange planet in general.

00:09:31 It is called the "twin of the Earth" because of our similarities,

00:09:35 although it is a little smaller than our planet.

00:09:38 But there are also drastic differences.

00:09:41 For example, it rotates in the opposite direction,

00:09:44 which means that the Sun rises to the west and sets to the east.

00:09:48 And Venus is not the only one to dance to its own rhythm.

00:09:52 Uranus does the same.

00:09:54 And finally, it's a bit of madness on Venus in terms of atmosphere.

00:09:57 When you are standing on Earth, you don't really feel the weight of the air around you.

00:10:01 Well, on Venus, this feeling would be comparable to an elephant sitting on your shoulders.

00:10:07 Venus has an atmospheric pressure 90 times higher than that of Earth.

00:10:11 The atmosphere there consists of a thick layer of toxic gases.

00:10:15 For example, the carbon dioxide that is released by all volcanoes.

00:10:19 It applies an incredible pressure.

00:10:21 This is translated by incredibly high temperatures.

00:10:24 It is therefore surprising that we still have to wait

00:10:27 before we can set foot on this planet one day.

00:10:30 Meanwhile, Mercury, the closest planet to the Sun,

00:10:33 has an orbit even shorter than that of Venus.

00:10:36 It makes a full journey around the Sun in only about 88 Earth days.

00:10:41 However, it has a slow rotation on its axis,

00:10:44 which means that one day on Mercury lasts about 176 Earth days.

00:10:48 Basically, half a year for us.

00:10:50 Just like with Venus, a day lasts much longer than a year.

00:10:54 As it is the closest planet to the Sun,

00:10:56 it is not surprising that Mercury knows of extremely high temperature variations.

00:11:01 During the day, these can exceed 420 ° C, enough to melt lead.

00:11:06 But wait for sunset.

00:11:08 At night, it goes down to a glacial -180 ° C.

00:11:12 It is because Mercury does not have a thick atmosphere like ours,

00:11:15 so the heat does not distribute uniformly across the planet.

00:11:19 If one side is plunged into darkness, it will be extremely cold,

00:11:23 and the other side will be burning.

00:11:25 Just like if you left an ordinary big rock under the sun for a moment.

00:11:30 In fact, it is so cold that there could even be ice on it.

00:11:34 Look at the region of the northern pole of the planet.

00:11:36 Especially these yellow spots, lit by the sun inside the craters.

00:11:40 They may indicate the presence of water ice.

00:11:43 And it turns out that the water is much more common in space than we thought.

00:11:47 Mars is often nicknamed "the red planet".

00:11:50 It owes its nickname to the abundance of iron oxide, or rust, which covers its surface.

00:11:55 The rich iron minerals create this reddish hue that colors the Martian landscape.

00:12:00 But it turns out that Mars is not just red.

00:12:02 If you stand on Mars, you will see a terrain similar to a desert of caramel colors,

00:12:07 bathing in a golden glow.

00:12:09 A little brown here and there, and even slight greenish reflections.

00:12:13 Mars also has the largest mountain in the entire solar system, Olympus, Mons.

00:12:18 At a dizzying height of about 22 km above sea level, it is much higher than Mount Everest.

00:12:23 It was formed by the eruption of a lava with low viscosity,

00:12:27 creating a structure similar to a shield.

00:12:30 Since Mars is covered with sand, it is also famous for its fantastic dust storms.

00:12:36 But it turns out that they are even more insensitive than we thought.

00:12:40 These storms can last months.

00:12:42 Although they may present challenges for future human missions,

00:12:46 they also contribute to the unreal aspect of the planet when it is observed from afar.

00:12:51 And it is not only the storms to take into account, but also the earthquakes.

00:12:56 Also known as seismic tremors, they were detected for the first time by NASA in 2019.

00:13:03 Unlike earthquakes, which are often triggered by tectonic plate movements,

00:13:08 we think that the tremors of Mars result from the cooling and contraction of the planet's interior.

00:13:14 It is interesting to see how similar and yet so different the two planets are.

00:13:20 Saturn's emblematic rings could hold a secret linked to the ancient past of the Earth.

00:13:25 These rings are mainly composed of ice particles and debris,

00:13:29 and are estimated to be relatively young on a cosmic scale, only a few hundred million years old.

00:13:35 Now, some theories claim that they were born after a large-scale disaster.

00:13:40 The collision of two large moons, or the disintegration of a comet, for example.

00:13:45 What is interesting is that this chronology coincides with the age of the extinction of dinosaurs on Earth.

00:13:51 Would there be a link? Who knows.

00:13:53 In fact, although Saturn wins the big prize for its rings,

00:13:56 it is not the only planet in our solar system to have it.

00:14:00 Jupiter, Uranus and Neptune also have their own sets of rings,

00:14:04 although they may not be as visible and impressive as Saturn's.

00:14:09 However, there is something by which Saturn really stands out.

00:14:13 The magnificent hexagon of its north pole.

00:14:16 It is a colossal figure with six sides.

00:14:18 And each side of this incredible structure measures about 14,500 km long,

00:14:24 or 1,900 km more than the diameter of the Earth.

00:14:28 Scientists are not sure how this hexagon was formed or why.

00:14:33 They think that this could be due to variable wind speeds.

00:14:37 Or maybe it was shaped by a localized, slow and sinuous jet stream.

00:14:42 For the moment, it remains another of Saturn's mysteries.

00:14:46 Like Saturn's hexagon, Jupiter also has its own strange spot.

00:14:50 It is called the Great Red Spot.

00:14:52 It is a storm that has been raging for at least 350 years and which is larger than the Earth itself.

00:14:59 Despite its name, the color of this point has varied over the years,

00:15:02 ranging from brick red to pale salmon pink.

00:15:05 Scientists continue to study this tenacious storm,

00:15:08 unravelling the mysteries of its persistence and its changing volutes.

00:15:12 On the meteorological level, the Great Red Spot is a real epicenter.

00:15:17 It generates enormous pressure in Jupiter's southern hemisphere.

00:15:21 During this time, Jupiter itself is not left out in terms of magnetic fields.

00:15:26 Its influence is colossal.

00:15:28 It extends far beyond the planet itself and creates one of the most vast and powerful magnetic fields in our solar system.

00:15:36 Because of this, Jupiter is a source of intense radiation and fascinating auroras.

00:15:42 While the auroras of the Earth's Boreal are breathtaking, Jupiter also has something to offer.

00:15:48 Its magnetic field interacts with charged particles from Jupiter's moons and solar wind.

00:15:54 This creates visually striking auroras at the level of its poles.

00:15:59 However, compared to the Earth, the scale of these auroras is phenomenal.

00:16:03 Nothing compares to what we observe on our planet.

00:16:07 But even this type of Great Red Spot is not a unique feature within our solar system.

00:16:13 The stormy giant, Neptune, the eighth and farthest from the planets of the Sun, also has its own Great Dark Spot.

00:16:22 Just like with Jupiter, it is a huge vortex in the middle of Neptune's atmosphere.

00:16:27 But unlike its Jupiterian counterpart, this spot tends to appear and disappear due to Neptune's extremely changing weather dynamics.

00:16:37 Neptune, like Uranus, is another frozen giant.

00:16:41 And like the other giants, it has some of the most violent winds in our solar system.

00:16:47 These supersonic currents can reach speeds of over 1,900 km/h.

00:16:53 Yes, it's not funny.

00:16:55 But this explains its thick cloud formations.

00:16:58 In fact, if you have ever dreamed of a planet where diamonds rain, you could be interested in this planet.

00:17:04 Deep in the atmosphere of Neptune, where the pressures are extreme,

00:17:08 scientists have hypothesized that carbon atoms would be so compressed that they would form diamonds.

00:17:14 These diamonds could then fall like rain.

00:17:17 What a unique touch for a beautiful storm.

00:17:19 Neptune's moons have inherited from their parents this strange weather.

00:17:24 For example, its largest moon, Triton, has a touch of cryovolcanism.

00:17:29 Instead of vomiting melting rocks like terrestrial volcanoes,

00:17:33 Triton's cryovolcanoes burst with a mixture of water, ammonia and nitrogen.

00:17:38 This is similar to ice geysers projecting their matter into space.

00:17:42 It seems that in our only solar system, each planet has its own fascinating peculiarities.

00:17:48 Let's hope we discover other interesting things in the space that is near the future.

00:17:53 Imagine.

00:17:55 You float in the depths of space and contemplate our dear blue planet.

00:18:00 Who is at the top?

00:18:01 You may think it's the North Pole, but it's not necessarily the case.

00:18:06 In fact, this collective belief that the North would be at the top of the world does not rely on any solid scientific basis.

00:18:13 It is simply something that we have accepted over time.

00:18:17 And this convention has an exciting history.

00:18:20 With a hint of astrophysics, a little psychology and a surprising consequence,

00:18:25 it influences our perception of the world much more than we think.

00:18:29 Knowing where we are is essential to survival.

00:18:32 And it's true for most species.

00:18:34 Not just for us, humans.

00:18:36 Like bees, for example,

00:18:39 human beings have the ability to create mental maps of their environment.

00:18:44 But where we really stand out is in our efforts to share these maps with our fellow humans.

00:18:51 We started doing it some time ago,

00:18:54 by drawing maps on all kinds of supports,

00:18:57 from cave walls to computer screens.

00:19:00 The oldest we have found date back to nearly 14,000 years.

00:19:05 Despite this long evolution,

00:19:07 it was only in the last centuries that we decided that the North should always be at the top of the map.

00:19:12 The ferrules of history will teach us that for a long time,

00:19:16 the North was practically never placed at the top of the map because it symbolized darkness.

00:19:21 The West was not taken into account either,

00:19:24 because that's where the sun died every night.

00:19:28 However, the first Asian maps seem to question this trend.

00:19:33 Before you think about it,

00:19:35 no, it's not because of their compass that they placed the North at the top of the map.

00:19:40 The first Asian compasses were actually aligned to the South,

00:19:43 considered a more favorable direction than the cold and darkness of the North.

00:19:48 But on these maps,

00:19:51 the emperor, who resided in the North, was always placed at the top.

00:19:55 This is a true story, raising our eyes to it.

00:19:59 In retrospect, each culture had its own notion of CE,

00:20:04 towards which it was better to be turned.

00:20:06 Which led to varied orientations of the first maps.

00:20:10 The Egyptians preferred the East,

00:20:12 where the sun gratifies us with its appearance every morning.

00:20:16 The first Arab maps favored the South.

00:20:19 The European maps of the same time placed the East at the top.

00:20:22 When everyone decided that the North was the new summit of the world,

00:20:26 one could be tempted to attribute the paternity to explorers like Christophe Colomb and Magellan,

00:20:31 who oriented themselves according to the polar star.

00:20:33 But they didn't really see the world from this angle.

00:20:36 Christophe Colomb, for example, saw the world with the East at its top,

00:20:40 believing that he was heading to the earthly paradise.

00:20:44 The Mercator projection of 1569 changed the situation,

00:20:48 because it was the first to take into account the curvature of the Earth for more precise navigation.

00:20:54 But even at that time, the emphasis was not placed on the North.

00:20:57 Mercator projected the poles to infinity,

00:21:00 considering them as relatively insignificant since the sailors never ventured there.

00:21:04 It is possible that the choice to place the North at the top

00:21:07 was motivated by the fact that the Europeans, who were accomplices in their part of the exploration,

00:21:12 were in the northern hemisphere, with much more land to cover and people to hang out with.

00:21:17 Whatever the reason, this idea of the North at the top remained.

00:21:22 Even when a NASA astronaut took a picture of the Earth with the South for the summit in 1972,

00:21:28 it had to be turned around to avoid any confusion.

00:21:31 This is where things get interesting.

00:21:33 When you observe the Earth from space, the notions of "up" and "down" lose all their meaning.

00:21:39 Certainly, the Earth aligns itself on the plan of the other planets of our solar system

00:21:44 because we all share the same cosmic origin,

00:21:46 but we could just as well reverse the image or place the Sun at the top or at the bottom,

00:21:51 depending on the astronomical point of view.

00:21:53 Even within the Milky Way, our solar system is tilted by about 63 degrees.

00:21:58 If you think about it, the notions of "up", "down", "left" and "right" do not really apply to space.

00:22:06 But why not reverse the "don"?

00:22:09 Should we accept to see our world from a different angle?

00:22:13 There is psychological evidence that our "Nordist" mentality could distort our perceptions of value.

00:22:19 Most people consider that the North is at the top and the South at the bottom.

00:22:23 Psychologists even wondered if these associations could influence the way people consider the different places on the map.

00:22:31 When they were shown the map of a fictional city, people were more and more inclined to choose a residence in the northern part.

00:22:37 And when they were asked where people with different social statuses would live,

00:22:42 they invariably placed the rich in the North and the poor in the South.

00:22:46 It is not an exaggeration to assume that humans care less about those who arrive in the lower regions than those where they are on the map.

00:22:53 But there is a simple solution.

00:22:56 Turn the map over.

00:22:57 Six experiments have shown that this simple action eliminates the bias according to which the North would be synonymous with "good".

00:23:04 In this regard, "backwards" maps are already available online.

00:23:08 Australians would appreciate this change, that's for sure.

00:23:11 Whatever you prefer, at the top of your world map, you will need a compass to guide you.

00:23:16 Have you ever stopped to think about this system?

00:23:19 It is one of the oldest gadgets we have in our survival kit.

00:23:23 It has existed for centuries, serving as a lighthouse for adventurers, for travelers and other explorers,

00:23:29 guiding them through unexplored oceans and helping them discover new continents.

00:23:34 In fact, the compass has transformed the sedentary man into a "Globetrotter" nomad.

00:23:39 Our beautiful blue planet is not only a sphere that spins in the cosmos.

00:23:43 It also has its own magnetic field.

00:23:46 Imagine it as a colossal magnet, swarming with an invisible energy.

00:23:51 All this thanks to the core of the Earth, a ball of fusion iron subjected to a colossal pressure, in the very center of our planet.

00:24:00 This core, half liquid, half solid crystal, vibrates and swirls under the effect of the rotation of the planet,

00:24:07 thus creating this magnetic field that gives us our poles, north and south.

00:24:13 But that's where things get a little rough.

00:24:16 These magnetic poles are not perfectly aligned with the geographical poles of the Earth, those around which the Earth rotates.

00:24:24 They are close, of course, but are not exactly in the same place.

00:24:29 This is why the compass, which reacts to the magnetic field, does not point directly to what we call the "real north",

00:24:35 that is, the geographical north pole.

00:24:38 It rather points to the magnetic north, located a little below the real one.

00:24:43 But don't worry, it's close enough to take us where we need to go.

00:24:47 Let's talk a little more about this story of "real north" and "magnetic north".

00:24:52 Do you remember the September 2019 news, which claimed that, for the first time in more than 360 years,

00:25:00 Greenwich's compasses indicated the "real north"?

00:25:03 It's a fairly rare fact.

00:25:05 In general, compasses indicate the magnetic north, which is not a constant point on the map.

00:25:10 It changes and changes over time, depending on the movements of the Earth's core.

00:25:14 On the other hand, the geographical north refers to the geographical north pole,

00:25:18 a precise and immutable point on the surface of the Earth.

00:25:22 So, when you hold a compass, it's towards the magnetic north that it points you, and not towards the geographical north.

00:25:28 This is where things get even more curious.

00:25:31 The angle between the geographical north's direction and the magnetic north's direction indicated by the compass is called "magnetic slope".

00:25:38 It's a sophisticated term for a simple concept.

00:25:41 Now, as the Earth's magnetic field is not easily apprehensible,

00:25:45 it has its hollows and its oscillations, the slope is not the same everywhere.

00:25:49 It varies from one place to another.

00:25:51 In addition, here is what constitutes a compass.

00:25:55 It is equipped with a tiny needle, designed from a magnetized metal,

00:25:59 iron being the most common.

00:26:01 This needle is fixed on a small pointy element, or pivot,

00:26:05 and left to flow in any liquid, often mineral oil or something similar.

00:26:10 This allows the needle to rotate and dance with the Earth's magnetic field.

00:26:15 When you hold your flat compass in your hand, the needle stabilizes and indicates the magnetic north.

00:26:21 Now, look at your compass and you will notice these little marks.

00:26:25 These are the degrees. And here's how to read it.

00:26:28 The red end of the needle is always pointing north, and the white or black end is always pointing south.

00:26:34 It's the north-south dance of your compass.

00:26:36 In addition, the compass chassis often has an arrow at the top.

00:26:39 It's the orientation arrow.

00:26:42 You've been training for years.

00:26:46 You know you're ready.

00:26:49 You hold on to the door's threshold, you breathe deeply and you open it courageously.

00:26:55 You jump outside the International Space Station and into the vastness of space.

00:27:01 "Ah, it's always so exciting," you say in your transmitter.

00:27:06 You feel as light as a feather in space, with the exception of the suit, of course.

00:27:12 It's true what this guy told you one day.

00:27:15 Astronaut suits limit the movement of the body by at least 20%.

00:27:20 For you, that means you have 20% chance of getting sick in space.

00:27:25 Which is not a good thing.

00:27:27 You don't get the right to make mistakes when you do this job.

00:27:30 You finally get to the docking station.

00:27:33 You look around you and you see the location of the station that needs to be repaired.

00:27:37 This is where the other shuttles dock when they arrive close to Earth or other planets.

00:27:42 A week ago, a shuttle from Jupiter miscalculated its arrival and broke part of the station.

00:27:48 You tied the piece to replace your belt.

00:27:51 Now, all you have to do is screw it.

00:27:54 You spent hours training underwater.

00:27:57 You wore a heavy, warm and uncomfortable suit in a pool

00:28:01 to know the exact movements you have to do here.

00:28:05 "Be careful," Sarah shouts on the transmitter.

00:28:08 You don't even have time to ask what it is.

00:28:10 A storm of debris takes you by surprise at an absurd speed.

00:28:14 It shakes everything around you.

00:28:16 You try to hang on to your safety cable, but...

00:28:19 Oh no, a debris comes from outside and is the visor of your helmet.

00:28:22 "Bob, are you okay?" Sarah asks you via the transmitter.

00:28:26 The impact shook you a little, but everything seems normal.

00:28:30 The meteorites have finally disappeared.

00:28:32 You can concentrate on your task.

00:28:34 You pull the cable to which the piece to be replaced is attached to you,

00:28:37 but there is nothing left at the other end.

00:28:40 No, nothing at all.

00:28:42 "Oh no," you say.

00:28:44 "Uh, Sarah, we lost a piece."

00:28:47 "I repeat, we lost a piece."

00:28:50 The situation is quite serious and you are aware of it.

00:28:53 Everything that falls into space can collide with the International Space Station

00:28:58 or with other vehicles.

00:29:00 You try to remember your training, but your head is empty.

00:29:04 It's worse than the time when you broke your girlfriend's favorite ceramic pot.

00:29:08 Sarah, the astronaut who accompanies you on board the station,

00:29:11 shouts on the transmitter.

00:29:13 "Oh no, Bob, tell me it's not true."

00:29:16 "It's a disaster, I'm coming."

00:29:19 You spot the piece in question under the ISS.

00:29:22 It is the size of a medium-sized car door and moves quite quickly.

00:29:27 Here's what can happen.

00:29:29 The piece can go back down to Earth and enter the atmosphere.

00:29:32 It will probably catch fire and disintegrate on the way.

00:29:36 But even if that's the case, the image of NASA will suffer and you will be reprimanded.

00:29:41 It is also possible that the lost piece will take a little momentum,

00:29:44 get into orbit and hit the ISS, and you too at the same time,

00:29:48 or a satellite that would be in the same orbit.

00:29:52 So there you go.

00:29:53 If you thought space was an infinite void, you were wrong.

00:29:57 Since different countries have started to build sufficiently solid equipment

00:30:01 to travel in space, the place is very crowded.

00:30:04 There are few people there, but there are satellites, asteroids and space debris.

00:30:10 You were surprised to learn one day that the Earth receives daily meteor shower.

00:30:15 But they are so small that no one on the planet's surface notices them.

00:30:20 They usually turn to ash before reaching the ground.

00:30:24 But that's not all.

00:30:25 What just happened to you on this mission has already happened on several other missions.

00:30:30 Astronauts are constantly losing objects in space.

00:30:34 So much so that NASA had to create a division charged with tracking

00:30:37 and monitoring the orbit of all these debris floating around the planet.

00:30:41 You wouldn't be surprised if you were told that there are more than 23,000 debris

00:30:45 the size of a bullet in orbit in space.

00:30:48 And half a million smaller objects.

00:30:51 While you are getting ready to detach your cable and venture dangerously into space without any protection,

00:30:56 you notice that Sarah is ahead of you.

00:30:59 You can't let her do that alone, so you decide to accompany her.

00:31:03 You know it goes against all NASA manuals and all the training you've been through.

00:31:08 But you tell yourself, if it works in the movies, it must work for us.

00:31:12 But you know perfectly well that it doesn't make any sense.

00:31:15 Sarah is close to the debris, but the weight of her body makes her orbit in a completely different direction.

00:31:21 "OK", you say, "it's your turn to shine and be a hero."

00:31:26 You try to move your arms as you would underwater, but there is no friction in space.

00:31:31 You can't start swimming to get that piece of equipment.

00:31:34 You try to contact Sarah, but she doesn't answer anymore.

00:31:37 So you're going to have to do it alone now.

00:31:41 For one reason or another, you start spinning in the same orbit as the lost piece.

00:31:49 It's probably because of the amount of things you've attached to yourself.

00:31:53 Maybe it's the burrito you ate this morning.

00:31:56 Do you feel like George Clooney in the movie Gravity?

00:31:59 No, even better. You feel like Obi-Wan Kenobi.

00:32:02 Yes, you feel as strong and powerful as a Jedi right now.

00:32:06 You keep your hands tense in front of you, hoping that the collision with the debris will be smooth.

00:32:12 And 3, 2, 1, landing successful.

00:32:15 I'm kidding, but yes, you managed to get to the debris.

00:32:19 "Hooray!" "And now," you say.

00:32:23 I guess you should have seen your plan a little more in depth, huh?

00:32:27 You don't have the possibility to guide the debris.

00:32:30 And you can no longer contact the mission control center to tell them that the object and yourself are on your way somewhere.

00:32:38 Don't be afraid. You didn't go all this way to start being afraid.

00:32:43 What are your options? First, mentally photograph your planet.

00:32:47 From up there, it never disappoints.

00:32:50 Then, ask yourself what are the different scenarios possible in such a situation.

00:32:55 Your normal weight can't be enough to get you out of the Earth's orbit.

00:32:59 In the hypothetical scenario where this would happen, you would probably be sucked into the orbit of Venus, and you would have a bad time.

00:33:07 It's extremely hot there.

00:33:09 Even if in mythology, Venus represents love, there is nothing pleasant in the neighborhood of this planet, and you know it.

00:33:16 If you got too close, your space suit wouldn't stand the heat.

00:33:21 It can only withstand a maximum temperature of 120 degrees Celsius, and the atmosphere of Venus can reach 370 degrees.

00:33:30 But honestly, the worst scenario is much simpler than that.

00:33:34 Your space suit could decide to drown your ears, your nose and your mouth in water.

00:33:39 Yes, this has already happened when you left space.

00:33:42 You see, for your space suit to stay fresh, it has to count on the 3.8 liters of water in its cooling system.

00:33:49 This system, which is supposed to eject air recycled from the back of your helmet, can start to flee.

00:33:54 And since you are stuck in the middle of nowhere, you have no place to go.

00:34:00 But wait, what is profiling on the horizon?

00:34:03 A modular space shuttle.

00:34:05 You try to scream, but no one can hear you outside your helmet.

00:34:09 You make signs with your arms. Here, it's heading straight for you.

00:34:13 "Finally," says Sarah. "I took a long time to find you."

00:34:17 Apparently, she came back to the station just in time to catch you before you left, wandering in infinite space.

00:34:24 "I guess I'm going to lose a few astronauts because of this little misadventure, huh?" you say.

00:34:31 "Yes, that's for sure."

00:34:36 Have you ever heard of the diamond star whose value exceeds that of all the riches of the Earth?

00:34:41 Or of those sparkling stars whose surface is made of solid iron?

00:34:46 Let's take a look at these strange stars and try to unravel their mystery.

00:34:50 There is a star in the constellation of Centauri that we nicknamed "Lucy in the Sky with Diamonds".

00:35:00 Yes, that's the title of a Beatles song.

00:35:04 We discovered that this star contained a massive diamond in its core.

00:35:09 But you may be wondering what the real size of this diamond is.

00:35:15 Well, it is estimated at about 10 billion billion billion carats.

00:35:20 A 1 followed by 34 zeros.

00:35:24 To put this into perspective, the Hope diamond, one of the largest diamonds on Earth, is only 45.5 carats.

00:35:33 Can you imagine the size of the ring you could make with this stellar diamond?

00:35:38 And it has about the same mass as our sun.

00:35:41 But don't get too fast with the idea of owning this diamond.

00:35:46 Even if you were Jeff Bezos, you couldn't afford it.

00:35:51 According to Ronald Winston, CEO of the Harry Winston company, the size of this diamond would risk dropping the prices on the market.

00:36:00 You will therefore have to settle for a ring much smaller.

00:36:04 An interesting thing about Lucy in the Sky with Diamonds is that it is incredibly dense.

00:36:12 Its mass is that of the sun, but within a diameter equivalent to one third of that of the Earth.

00:36:18 As if you were trying to get an elephant into a shoebox.

00:36:22 And yet, despite this imposing size, it is relatively cold.

00:36:27 With a central temperature of only about 6,649 ° C.

00:36:32 In comparison, the central temperature of our sun is about 15 million degrees.

00:36:37 Since the discovery of Lucy in the Sky with Diamonds, we have found several other crystallized stars, some of which have a heart of a diamond the size of the Earth.

00:36:48 This proves that the universe is full of surprises, and that we never know what kind of treasure we will discover in the vast expanse of space.

00:36:57 We have found other curious stars.

00:37:00 There are many strange and unexplained things in space.

00:37:05 Let's take the example of Vega.

00:37:09 Vega, also called Alpha Lyrae, is a star located in the constellation of Lyra.

00:37:15 It is one of the brightest stars in the night sky, and it is easily visible to the naked eye in most regions of the world.

00:37:23 For us, inhabitants of the northern hemisphere, Vega is a beautiful luminous star.

00:37:28 But we have discovered one of its secrets.

00:37:32 It is actually a little crushed.

00:37:35 Its rotational speed makes it swell to the equator, as if it had a little belly.

00:37:42 It rotates once every 12.5 hours, which is quite fast for a star.

00:37:49 And it projects matter around it. It's a bit like it's doing hula hoop.

00:37:54 This matter, being quite far from its center, therefore undergoes less gravity, which cools it and darkens it.

00:38:01 This is called darkening by gravity.

00:38:04 Vega is therefore the worst nightmare of a fitness cosmic advisor.

00:38:11 For us who observe it, it always seems round, but it is actually a little round.

00:38:18 It always seems round because we look at it from the end of the pole of the Earth.

00:38:22 If we observed it from another angle, we would have a very different view.

00:38:26 And we would wonder if Vega does not swell from a cosmic bath when we turn its back.

00:38:32 But even if we make fun of its size, it is undeniable that Vega remains one of the most fascinating stars in our galaxy.

00:38:47 But you want to see something really bright? What would you say about a supernova?

00:38:51 Supernovas are gigantic explosions that occur when stars reach the end of their lives.

00:38:58 It's like the final bouquet of a firework, but on a cosmic scale.

00:39:04 It releases more energy in a few seconds than our sun will produce for its entire life.

00:39:10 And that's exactly what happened to the star we're going to see now.

00:39:17 A celestial object named IPFT I4HLS.

00:39:22 But there is a hiccup. It is not an ordinary supernova.

00:39:27 This star exploded well in 2014 and began to go out as expected.

00:39:32 But then it started to shine again.

00:39:35 You're talking about a stage entrance.

00:39:42 And as if that were not enough, it continued to go out and then lit up at least five times in total.

00:39:47 A bit like a yo-yo.

00:39:49 It's as if it couldn't decide whether it wanted to keep shining or go out forever.

00:39:55 In addition, when scientists measured the spectrum of this supernova,

00:40:02 they found that it was evolving ten times slower than the other stars.

00:40:06 Maybe it just wants to enjoy its old age a little.

00:40:11 In short, this object is a real mystery.

00:40:14 But it is not the only star suffering from two-in-one syndrome.

00:40:19 At first glance, MY Camelopardalis seems quite ordinary.

00:40:25 But looking closer, astronomers have discovered that it is actually two stars.

00:40:31 They rotate around each other with a constant speed of about 10,000 kilometers per second.

00:40:39 And they move around each other at more than 950,000 kilometers per hour.

00:40:42 This is a binary stellar system in contact.

00:40:46 Which means that the stars are so close to each other that they share a common envelope.

00:40:50 In other words, they are so close that they literally "bend".

00:40:54 These Romeo and Juliet stars are one of the most massive binary stars we know.

00:41:02 They weigh respectively 32 and 38 solar masses.

00:41:07 And our astronomers think they could be about to merge.

00:41:10 Which means that one day, they could combine to form a super giant star.

00:41:16 Who would have thought that space could be so romantic?

00:41:20 Here is another name for it.

00:41:24 HD 140283, the star Methuselah.

00:41:29 This planet is called the "Methuselah" because it is the birthplace of the first human race.

00:41:36 This little man in the constellation of the balance has existed for a while.

00:41:40 And by a while, I mean a very, very long time.

00:41:43 In fact, scientists thought it was older than the universe itself.

00:41:47 Imagine if that was true.

00:41:52 But they ended up discovering that it was about 14 billion years old.

00:41:57 That is, the same age as our universe.

00:42:00 It's still pretty impressive.

00:42:04 It is so old that it remembers the time when the Milky Way was just a small galaxy.

00:42:08 Despite everything, it still has a little life in it.

00:42:15 It is just starting to transform into a red giant.

00:42:19 Which is a bit like when you reach thirty.

00:42:22 So it is getting old pretty well.

00:42:24 But if all these things remain more or less understandable,

00:42:30 we will soon see this star, which astronomers have nicknamed WTF, or "What is this thing?"

00:42:35 It is now called Tabby's Star.

00:42:39 It also has a more scientific name.

00:42:43 But it is a bit long.

00:42:45 What is really strange about it is its irregular brightness.

00:42:51 For some unknown reason, it does not shine like a normal star.

00:42:55 It flashes, like when you turn on and off a flashlight.

00:42:59 And it is not a small decrease in brightness, but a 22% decrease.

00:43:03 So it is not because an object would come to hide it from time to time.

00:43:07 Scientists have all kinds of theories about this strange behavior.

00:43:13 Comets, dust, an extraterrestrial megastructure.

00:43:18 Yes, but before your imagination gets carried away,

00:43:22 it is important to note that the most probable explanation is that of dust.

00:43:27 The star would be surrounded by a kind of cloud of dust,

00:43:31 which would sometimes prevent us from seeing it clearly.

00:43:34 But this explanation is not yet 100% confirmed.

00:43:40 And there are still many mysteries surrounding Tabby's Star.

00:43:43 One thing is certain, it may be a bit weird, but that's what makes it so fascinating.

00:43:49 And here we are, my friend.

00:43:54 We are amazed by the incredible diversity and strangeness of the cosmos.

00:43:58 There are still so many things to discover.

00:44:01 So let's continue exploring the universe in search of these fabulous treasures.

00:44:05 The Earth is not flat, but Jupiter could have been.

00:44:09 Instead of large round spheres, the gas giants of our solar system

00:44:13 may have started their lives by being just simple crepes.

00:44:16 Jupiter was one of our oldest neighbors.

00:44:19 It is 4.6 billion years old, just like our sun.

00:44:23 And when it was still young, it probably formed in a protoplanetary disk.

00:44:27 It all starts with stars.

00:44:31 When a star is still forming, it does not look like a round object.

00:44:35 It is more like a large disk of matter.

00:44:37 At this stage, hot winds blow, composed of charged particles.

00:44:41 The dust of this disk contains elements such as carbon and iron.

00:44:46 Some of them collide and remain together, forming larger objects.

00:44:52 Dust turns into pebbles, pebbles turn into rocks,

00:44:56 and rocks collide with each other, becoming larger and larger.

00:45:00 The gas present in the disk helps all these solid pieces to agglutinate.

00:45:04 Some detach, but others remain together.

00:45:07 And it is they who become the basis of the planets.

00:45:10 They are called planetesimals.

00:45:12 Even gas giants like Jupiter started as tiny particles of dust,

00:45:17 smaller than a human hair.

00:45:21 They formed their own disk of matter.

00:45:23 Then they started to spin around our sun,

00:45:27 growing as they accumulated gas and rocks, like a big snowball.

00:45:32 Gas giants are special.

00:45:37 They are born from the coldest parts of the disk.

00:45:40 In these cold regions, the molecules are slower,

00:45:43 which makes them easier to capture.

00:45:47 The ice can freeze, and tiny pieces of ice stick together and mix with dust.

00:45:52 These snowballs gather and then form the cores of vast planets like Jupiter, Saturn, Uranus and Neptune.

00:46:01 In the warmer regions, close to the star,

00:46:04 teluric planets like Mercury, Venus, Earth and Mars begin to form.

00:46:09 After the birth of the ice giants, there was not much gas left for these little celestial bodies,

00:46:16 and it could take tens of millions of years for such planets to form after the birth of a star.

00:46:21 Our sun was growing at the same time, sucking in the gas close by and pushing the distant objects even further.

00:46:27 After billions of years, the disk has completely changed,

00:46:31 transforming into a spherical star with a bunch of giant and tiny planets,

00:46:36 asteroids, moons, meteorites and comets around.

00:46:45 Recently, simulations have shown that these protoplanets,

00:46:47 as we call these first dust conglomerates,

00:46:50 did not start by looking like the planets we know.

00:46:53 In the case of gas giants like Jupiter,

00:46:56 they would look more like crushed balls or M&Ms.

00:47:00 When the sun was still young,

00:47:02 the gas and dust disk that surrounded it cooled down and became unstable.

00:47:07 It began to break up into large pieces.

00:47:11 These gathered under the effect of an implacable gravity to create Jupiter.

00:47:15 Then it became a giant gas giant of spherical shape over time.

00:47:19 Numerous anomalies can occur during this process of planet formation.

00:47:23 Have you ever wondered why Venus or Uranus were rotating in the opposite direction?

00:47:28 Usually, when things are formed from a rotating gas disk,

00:47:33 they tend to rotate in the same direction.

00:47:36 If you spin a bunch of balls tied to a string, for example,

00:47:40 they will all rotate in the same way.

00:47:42 So, theoretically, all planets should also rotate in the same direction.

00:47:47 But there are also many objects that move quickly in our solar system,

00:47:52 like comets and asteroids.

00:47:54 When they collide with planets, especially during their first days,

00:47:58 this impact can lead them to rotate in the opposite direction.

00:48:02 Venus and Uranus probably survived a large-scale collision.

00:48:06 Fortunately, they were not ejected into space.

00:48:09 The gravity of the Sun and neighboring planets kept them in their place.

00:48:14 There are also what are called planets locked gravitationally.

00:48:21 These are celestial bodies that rotate,

00:48:24 so that one side is always facing their star,

00:48:27 while the other remains in perpetual darkness.

00:48:30 So one side is always very hot, while the other is extremely cold.

00:48:35 If we lived on such a planet, we could only exist on a thin band between these two extremes.

00:48:40 These planets form when they are very close to their star.

00:48:44 The gravitational forces at work are intense and, over time,

00:48:48 slow down the rotation of the planet until it corresponds to the time it takes to orbit around its star.

00:48:55 Imagine that you are turning on your chair.

00:48:57 Someone approaches you and, holding your chair in his hands,

00:49:01 starts to turn with you.

00:49:04 You will face each other all the time.

00:49:06 Synchronous rotation planets work a little like this.

00:49:09 Our Moon is also in synchronous rotation with the Earth.

00:49:13 That's why we only see one side of it.

00:49:16 We have discovered more than 5,000 exoplanets outside our solar system.

00:49:22 Some of them have very strange orbits.

00:49:25 There are some, for example, that have incredibly long orbits,

00:49:30 thousands of years to make a single revolution around their star.

00:49:34 Or very unequal orbits, similar to those of comets.

00:49:37 Or those planets that are called "hot Jupiters",

00:49:40 which are very close to their star, much closer than Mercury is to our Sun.

00:49:45 But these planets could not have formed where they are now.

00:49:49 As their solar system evolved, they, for one reason or another, changed positions.

00:49:55 This rearrangement is called "planetary migration".

00:49:59 There are three ways this migration can occur.

00:50:02 First, due to the gas and dust in rotation around the planet.

00:50:07 When a planet collides with this matter, it can create spiral patterns in the gas.

00:50:13 These patterns can either bring the planet closer to the center,

00:50:17 or move it away, depending on how they mix.

00:50:20 This is called a "type I" migration.

00:50:23 This is what Jupiter experienced when it moved closer to the Sun.

00:50:28 This is what Jupiter experienced when it moved closer to the Sun billions of years ago.

00:50:30 This also explains the existence of "hot Jupiters".

00:50:33 Second, large planets can move smaller ones, changing their trajectory.

00:50:39 Third, the gravity of the star can attract the planet, making its orbit circular.

00:50:45 Have you ever heard of wandering planets?

00:50:51 Imagine a lonely planet, floating in the vastness of space,

00:50:56 and being tied to the smallest star.

00:50:58 These are the wandering nomads of our galaxy, condemned to wander eternally.

00:51:02 And there are so many of them.

00:51:04 There could be more planets in freedom than planets linked to a star.

00:51:08 We are talking about thousands of billions of wandering bodies in our only milky way.

00:51:14 It is not uncommon for them to be as massive as our largest planet, Jupiter.

00:51:19 But most of them would be a size more comparable to that of the Earth.

00:51:24 There are even some that could have a thick atmosphere capable of keeping them warm.

00:51:27 Although they are the eyes of every star,

00:51:29 some of these planets could have horrors to cut the breath,

00:51:33 while others could be in the towers of moons containing liquid helium,

00:51:37 a potential haven for life.

00:51:39 There is even a chance that they could inhabit an extraterrestrial life.

00:51:43 These planets could hit other stars, or even entire planetary systems,

00:51:47 during their crazy races through space.

00:51:50 Sometimes, they could be captured by the gravity of a star for a certain time,

00:51:54 before being ejected back into space.

00:51:56 But how do they come to be?

00:51:58 Sometimes, during this chaotic formation process,

00:52:01 all the planets fail to stay close to their star-like relatives.

00:52:05 Some of them are expelled from their solar system,

00:52:08 due to the gravitational attraction of other planets, or passing stars.

00:52:14 These ejected planets then become wandering planets.

00:52:19 In 2012, astronomers discovered a solar system dating from the beginning of the universe.

00:52:25 This system includes a star and two planets.

00:52:28 It was nicknamed the "fossil system".

00:52:31 Its star is incredibly old,

00:52:34 about 13 billion years old,

00:52:36 almost as old as our universe itself.

00:52:39 This system is mainly composed of hydrogen and helium.

00:52:44 This is unusual, because planets are generally formed from gas clouds containing heavier elements.

00:52:50 This is when we realized that the way planets were formed before

00:52:54 was different from the way they are formed today.

00:52:58 We know that the stars containing the most metals

00:53:01 are the most likely to have planets.

00:53:03 In astronomical terms,

00:53:05 "metal" means any chemical element other than hydrogen and helium.

00:53:11 But in the primitive universe, there were not many heavy elements.

00:53:14 Most of them were created inside the stars,

00:53:17 and then dispersed in space when they exploded.

00:53:21 So, when did the very first planets form?

00:53:25 This newly discovered system helps to answer this question.

00:53:29 These two giant planets are orbiting around a star,

00:53:32 which is incredibly poor in metals and extremely old.

00:53:36 It should be very rare, if not impossible,

00:53:40 but they exist, nevertheless.

00:53:41 This may mean that there are more planets in poor metal systems than we thought.

00:53:46 The study will help us learn more about the formation of planets.

00:53:51 What you are looking at is by far the most successful portrait of our sun.

00:53:56 Fortunately, our star, 4.5 billion years old,

00:54:00 did not use makeup to arrange its hue before this photo session,

00:54:04 and we can now study its surface in detail.

00:54:08 This emblematic picture was taken in March 2022.

00:54:10 NASA wanted to acquire a better understanding of the behavior of our star

00:54:14 and its impact on terrestrial life,

00:54:16 and to consider the future of our space technologies, of course.

00:54:20 To do this, we launched the satellite of the Solar Dynamics Observatory, or SDO,

00:54:25 in February 2010.

00:54:27 This legendary photo session took place 12 years later,

00:54:30 when the SDO was halfway between the Earth and the Sun.

00:54:35 The SDO had to assemble 25 individual images in the form of a puzzle.

00:54:38 Thus, the final image contains 83 million pixels.

00:54:42 And yes, this resolution is about ten times higher than that of the screen of your 4K TV.

00:54:47 Look at this incredible pattern that looks like the crust of a biscuit.

00:54:51 Usually, the sun's bright surface hides it from us when we observe the star from Earth.

00:54:56 Fortunately, NASA has explored this light beyond the observable spectrum,

00:55:00 which has allowed it to discover invisible details of the face of our sun.

00:55:04 When we adjust a selfie with filters and effects,

00:55:07 we can get completely different portraits,

00:55:10 highlighting different parts of our face.

00:55:13 Even those that we didn't even know existed.

00:55:16 The same principle applies here.

00:55:18 Each of these plasma balls is the same photo of the sun,

00:55:21 taken at different electromagnetic wavelengths.

00:55:24 The spots and patterns revealed can help us to better understand

00:55:27 the events that occur under the skin of our star.

00:55:31 At the speed of light, it usually means something extremely fast.

00:55:34 However, this golden-pink ray that caresses your cheek at dawn

00:55:38 has traveled a long way and is incredibly old on a human scale.

00:55:42 Photons generated by the core of the sun take between 10,000 and 170,000 years

00:55:47 to cross the atmosphere of the star,

00:55:49 then about eight more minutes to reach Earth.

00:55:52 So let's explore why it takes them so long.

00:55:55 Our visit begins with the upper layer of the atmosphere of the sun.

00:55:59 To create these solar deities in the paintings and plays of the Baroque era,

00:56:02 they often wear luxurious crowns with golden-pink rays.

00:56:06 Well, the sun itself also wears a beautiful crown,

00:56:09 which is the external layer of its atmosphere.

00:56:11 But of course, its greatness and glory are incomparable

00:56:14 to those of these "legboard-shaped" costume crowns,

00:56:17 and its shape is not so regular.

00:56:19 The crown is a gas envelope that envelopes our star,

00:56:22 so that its size and shape fluctuate constantly

00:56:25 under the influence of the magnetic field of the sun.

00:56:28 You can see this crown from your own eyes from Earth

00:56:31 during total solar eclipses.

00:56:33 It looks like a sublime radiation around the solar disk,

00:56:36 which itself is then completely masked by the moon.

00:56:39 The crown extends over 8 million kilometers above the surface of the sun,

00:56:43 while our blue planet is only 13,000 kilometers in diameter.

00:56:48 Thus, the hypothetical radius of the crown would be equivalent

00:56:51 to a line of about 625,000 planets the size of the Earth.

00:56:56 And suddenly, all my problems begin to seem tiny.

00:56:58 And here is another singular fact.

00:57:00 The crown of the sun somehow derogates the laws of known physics,

00:57:04 because it is warmer than it should be.

00:57:06 Its temperature is more than 1 million degrees Celsius,

00:57:09 while the surface of the sun is only about 5,000 degrees.

00:57:13 That said, the adverb "only" is not the most appropriate,

00:57:16 because it is always extremely hot in human terms.

00:57:19 Usually, the temperature tends to drop

00:57:22 when we move away from a source of heat.

00:57:25 But this is not the case here.

00:57:27 Astrophysicists remain perplexed by such a mystery.

00:57:30 Fortunately, this recent photo session allows us to discover

00:57:33 what is happening inside this huge incandescent ball

00:57:36 without risking losing sight of it.

00:57:38 Take, for example, these magnificent luminous points.

00:57:41 They represent the solar eruptions that occur under the layer of the crown.

00:57:45 These are powerful explosions that occur

00:57:48 when magnetic fields collide with each other.

00:57:52 When they occur, they change shape and react quickly.

00:57:55 These magnetic fields come from plasma,

00:57:58 which is itself very turbulent,

00:58:00 so that such events are not surprising for the local weather.

00:58:03 Who would have thought that the sun had black spots on its skin,

00:58:06 just like teenagers?

00:58:08 These darker areas are known as coronal holes.

00:58:11 Earthlings can admire the impact

00:58:13 when they observe these magnificent auroras in the polar regions.

00:58:17 The coronal holes seem darker

00:58:20 because the plasma in these regions is colder,

00:58:22 less dense and open magnetically.

00:58:24 These conditions allow solar winds to spread through the solar system

00:58:29 rather than stay on the surface of the star.

00:58:31 And when they hit the Earth's magnetosphere,

00:58:33 these auroras form to delight our eyes.

00:58:36 Fortunately, our local magnetic field cools the solar winds.

00:58:40 Nobody would want to see their eyes melt, would they?

00:58:43 Now, if we were looking for an equivalent to the hair of the sun,

00:58:48 the best candidates would be solar storms.

00:58:50 Sixteen large, shiny plasma loops rise from the surface of the sun

00:58:54 and stretch for thousands of kilometers in space.

00:58:57 Their lifespan varies from a few days to several months.

00:59:00 It is one of the most common events in this region.

00:59:03 Although the first detailed description of a solar storm dates from the 14th century,

00:59:07 modern scientists are still looking for how and why they form.

00:59:12 By diving deeper, we are confronted with the transition zone.

00:59:17 The thickness of this layer is about 100 km,

00:59:19 and the local weather is clearly crazy.

00:59:22 Temperatures can rise up to 500,000 degrees.

00:59:25 This transition zone is located between the crown

00:59:28 and the last region of the atmosphere of the sun,

00:59:30 which is called the chromosphere.

00:59:32 Speaking of which, this is precisely our next stop.

00:59:35 The chromosphere is known to present a scientific mystery

00:59:38 called the sphincter.

00:59:40 Repeat it 20 times very quickly.

00:59:42 Sphincter, sphincter, sphincter.

00:59:45 In addition, this spectacular plasma jet stretches from the surface of the sun

00:59:49 and reaches speeds of about 360 km per second.

00:59:52 As if they were jumping on a trampoline from the surface of the sun.

00:59:56 Each sphincter lasts a few minutes in space

00:59:59 before falling back into the solar atmosphere.

01:00:01 Astrophysicists had a hard time explaining how charged particles

01:00:05 could magnetically escape the incredible gravity of the sun

01:00:09 while being so close to it.

01:00:11 A possible answer appeared in 2017.

01:00:14 A group of scientists discovered that neutral particles

01:00:17 provided particles charged with a magnetic charge

01:00:20 with additional buoyancy

01:00:22 allowing them to tear away at solar gravity for a while.

01:00:25 Which is still better than the explanation of the pearly powder, isn't it?

01:00:29 Let's now move 1,600 km through the chromosphere

01:00:33 to finally reach the solar surface, or photosphere.

01:00:36 It measures about 400 km in thickness.

01:00:39 But unlike the planet Earth,

01:00:42 the surface of the sun is neither stable nor solid.

01:00:44 The temperatures here are so high that no matter can exist.

01:00:48 On the other hand, scientists often call plasma

01:00:52 the fourth state of matter.

01:00:54 And why not?

01:00:56 It is made of ionized atoms and free electrons.

01:00:58 And it deserves to be considered as such.

01:01:01 Maybe one day, we will have the opportunity to meet

01:01:04 a local species of plasmoid person.

01:01:07 But I think it would be better if we avoided their warm welcome.

01:01:11 You know, such people would surely have a volcanic temperament.

01:01:16 Anyway, the photosphere is our last step.

01:01:19 Because humanity does not yet have the technology

01:01:22 to explore the sun more deeply.

01:01:24 So, if we want to learn more about it,

01:01:27 you will have to invent your own space machine.

01:01:29 But time is running out.

01:01:31 You only have 7 to 8 billion years.

01:01:33 After that, our sun will go out,

01:01:35 according to the estimates of scientists.

01:01:37 And, to tell the truth,

01:01:40 the scientists will surely be the first on the shot.

01:01:42 You have a serious competitor.

01:01:44 The Parker Solar Probe of NASA currently holds the record

01:01:47 of the deepest dive in our sun.

01:01:50 This space machine has managed to travel 7,300,000 km

01:01:54 from the surface of the sun to its core on September 27, 2023.

01:01:58 And since then, the Parker probe has reiterated the feat in December of the same year.

01:02:03 So, why didn't it melt, you may ask?

01:02:07 The probe was designed to resist the most extreme conditions

01:02:10 and temperature fluctuations.

01:02:12 It is equipped with a custom-made thermal shield

01:02:15 and an autonomous system protecting the mission against intense solar radiation.

01:02:19 NASA has other ambitious plans.

01:02:21 In December 2024, Parker will get even closer to the sun.

01:02:26 It will move faster than any other object man-made,

01:02:29 at a speed of 700,000 km / h.

01:02:34 The probe will then be only 6 million km from the burning surface of the sun.

01:02:38 It's practically like landing on a star.

01:02:40 Astronomers have already compared this next step to our first moon landing.

01:02:44 Finally, it would probably be better if we landed at night.

01:02:48 Okay, I admit it.

01:02:50 It's an old joke like the world.

01:02:52 1994.

01:02:55 It was dark.

01:02:57 So that no one noticed the two silhouettes opening the emergency exits

01:03:02 of a glass dome located in Arizona and known as Biosphere 2.

01:03:05 They were determined to free 7 people locked inside for a month,

01:03:10 risking their lives in the name of science.

01:03:12 The mission was a success,

01:03:14 but they were accused of property violation and vandalism.

01:03:18 The vandals were Tabby Gail Alling and Mark Vantillo.

01:03:21 They were among the first 8 unfortunate people to live in this place like guinea pigs.

01:03:26 And they didn't want others to suffer the same horrors they had experienced.

01:03:31 $150 million was spent to determine

01:03:33 if humans could create suitable living conditions on other planets, like Mars.

01:03:38 To do this, scientists built a mini-world with more than 3,000 species of plants and animals.

01:03:44 Biosphere 2 was a 12,000 square meters habitat,

01:03:48 completely isolated, with its own mini-tropical forest,

01:03:51 a private beach with a coral reef,

01:03:54 a small savannah, a swamp, and even a piece of desert.

01:03:59 Between 1991 and 1993, nothing could enter or leave this place.

01:04:03 The group of 8 people locked inside were called the Biosphere 1,

01:04:08 and wore suits like Star Trek,

01:04:11 growing their own food and breathing their own air.

01:04:15 It all started with great hopes and a breakfast worthy of a 5-star hotel.

01:04:20 But things took a darker turn over the months.

01:04:23 The whole team was starving and went to the Orange.

01:04:27 In Biosphere 1, our good old Earth,

01:04:29 you can order a pizza in 2 minutes.

01:04:32 But inside Biosphere 2, they spent 4 endless months preparing a margherita.

01:04:37 They had to harvest wheat for the dough, and goat for the cheese.

01:04:41 The goal was to be completely self-sufficient,

01:04:44 and they became an integral part of their atmosphere, literally.

01:04:48 When they exhaled, their carbon dioxide fed the sweet potatoes they grew.

01:04:54 The sweet potatoes became a part of themselves,

01:04:57 since they were eating the same carbon again and again.

01:05:00 They ate so much sweet potatoes that their skin turned orange,

01:05:04 because of all this beta-carotene excess.

01:05:07 What seemed to be a fun situation at the time,

01:05:10 turned out to be a big problem.

01:05:12 The agricultural yields in Biosphere 2 were extremely disappointing,

01:05:16 and the team was starving.

01:05:18 Hunger drove them crazy,

01:05:21 and sudden anger led them to do regrettable things,

01:05:24 like stealing bananas in the basement.

01:05:26 After a while, they had to lock the freezer.

01:05:29 During the first 6 months, each of them lost between 8 and 26 kilos.

01:05:34 Every day, someone weighed the fresh food for the cook,

01:05:38 delivering all the information on the nutrients to the computer,

01:05:41 to make sure that the crew reached its recommended yields in calories,

01:05:45 protein, and fat.

01:05:47 At first, meals were served in the form of buffets.

01:05:50 But as the food began to run out,

01:05:53 the cooks began to divide their food into equal portions meticulously.

01:05:58 Their diet, mainly sweet potatoes, carrots, fruits,

01:06:02 and occasionally meat on Sundays,

01:06:04 was supposed to allow them to hold on during these exhausting 80-hour weeks,

01:06:08 made of exhausting manual work.

01:06:11 The Biosphere team left each meal still hungry,

01:06:14 and had recurring dreams of Big Mac,

01:06:17 sushi, chocolate bars, and other cakes.

01:06:20 The air began to be lacking.

01:06:22 The place was completely sealed,

01:06:24 with a glass dome and steel at the top,

01:06:26 and a floor made of the same metal at the bottom.

01:06:28 The managers made sure to control everything that entered,

01:06:31 to prevent synthetic materials from emitting harmful gases.

01:06:35 The comfort areas were fenced with wood and wool,

01:06:39 and no chemical deodorant or birthday candles could be blown in there.

01:06:45 The Biosphere team relied on the food they grew,

01:06:47 and on their mini tropical forest,

01:06:49 to produce the oxygen necessary for their survival.

01:06:52 However, they were losing oxygen very quickly,

01:06:55 suffocated by their own carbon dioxide emissions.

01:06:58 And the worst part is that they had no idea why.

01:07:01 With another 9 months of experience to endure,

01:07:04 the oxygen level had already dropped from 21 to about 15%,

01:07:08 which gave the impression of living at the top of Mount Fuji.

01:07:13 They felt terribly sick,

01:07:14 and dragged themselves painfully through the Biosphere.

01:07:17 They couldn't even finish a sentence without stopping to catch their breath.

01:07:21 Then the apnea of sleep began to appear,

01:07:24 some waking up out of breath.

01:07:26 To reduce the CO2 levels inside the Biosphere 2,

01:07:30 they tried a few desperate maneuvers,

01:07:32 like pushing plants at a crazy pace,

01:07:34 reducing the soil's water as much as possible,

01:07:37 and even giving up plowing their crops.

01:07:40 Nothing worked.

01:07:42 Everyone agreed that they were not far from touching the bottom,

01:07:45 and they decided to ask for help.

01:07:47 Fridge trucks arrived to pump pure oxygen into Biosphere 2.

01:07:52 As soon as the gas began to spread,

01:07:54 they started laughing out loud,

01:07:56 and running around like cabrioles.

01:07:58 The ecosystem was a real disaster.

01:08:00 The hummingbirds and bees disappeared after a few months,

01:08:03 so that the plants were no longer pollinated.

01:08:05 The greens and the acarians attacked the crops,

01:08:08 and the cockroaches invaded everything.

01:08:11 Four species of cockroaches were introduced to recycle organic matter,

01:08:14 but the ordinary domestic cockroaches were the ultimate survivors.

01:08:19 They managed to infiltrate and multiply,

01:08:22 posing a serious threat to the crops.

01:08:24 At night, the kitchen was full of cockroaches as soon as the lights went out.

01:08:28 To fight this infestation,

01:08:30 the group greased coffee cups with lubricant,

01:08:33 and put pieces of papaya in them to serve as a starter.

01:08:36 The cockroaches climbed inside,

01:08:40 but they could no longer climb the sliding edges to escape.

01:08:42 Being hungry, lacking oxygen,

01:08:44 facing insect infestations,

01:08:46 it would be enough to drive anyone crazy.

01:08:49 Violent disputes led people to throw cups at each other

01:08:53 and spit on each other.

01:08:55 In the end, the group simply split in two.

01:08:58 They stopped talking to each other,

01:09:00 and could meet in the corridors without even looking at each other.

01:09:03 Half of them wanted more food and oxygen

01:09:06 to continue the experiment with dignity,

01:09:09 while the other half believed in their chance of survival without external help,

01:09:12 and whatever it costs.

01:09:14 In truth, the sealed room had been violated long before all this.

01:09:18 Just two weeks after their entry,

01:09:20 a biospheric woman named Jane Pointer

01:09:23 cut her finger in a kitchen accident while preparing rice.

01:09:27 The mission doctor tried to sew it back together,

01:09:29 but it didn't work,

01:09:31 and her finger turned black in a few days.

01:09:33 She went to an external hospital to be operated on,

01:09:37 and a few hours later, she returned inside

01:09:39 with a bag of sports filled with supplies,

01:09:42 like computer parts and colored films.

01:09:45 The journalists only discovered this stealth delivery

01:09:48 many months later,

01:09:50 and because of this, many people questioned

01:09:53 the credibility of the entire experiment.

01:09:55 The media treated the experiment as a reality TV show,

01:09:59 calling it "ecological entertainment in fashion".

01:10:02 The big titles from all over the world

01:10:05 made it seem like the team was about to die.

01:10:07 To the point that their families were worried,

01:10:10 and kept calling the biospheric people to make sure they were doing well.

01:10:14 The group seemed to be in a human zoo,

01:10:17 with tourists from far away

01:10:19 to watch them through their glass cages.

01:10:22 In just the first six months,

01:10:24 more than 150,000 people visited the place.

01:10:27 Biosphere 2 ended up becoming a gag in popular culture,

01:10:32 and a comedy called "Biodome", and decades of funny sketches.

01:10:35 You may be wondering why none of them gave up the experiment

01:10:38 and didn't go out the front door.

01:10:40 Well, none of the environmentalists

01:10:42 wanted to be the first to admit

01:10:44 that it was beyond their strength.

01:10:46 In addition, they all still kept the hope

01:10:49 of being able to take up the challenge

01:10:51 of building a second Earth.

01:10:53 In the end, they managed to discover

01:10:55 where the 7 tons of oxygen was missing.

01:10:58 It had been absorbed by the concrete.

01:11:01 Even though being breathless all the time

01:11:02 may seem to have been the biggest challenge

01:11:04 they had to face,

01:11:06 the biospheric people declared that learning

01:11:08 how to make contact with humans in a closed environment

01:11:10 was even more difficult.

01:11:12 It seems that the experiment was a huge fiasco.

01:11:15 But the group learned a lot of valuable lessons.

01:11:17 They proved that a sealed ecosystem

01:11:19 could function for years.

01:11:21 They contributed to studies

01:11:23 on the restoration of coral reefs.

01:11:25 And their farm showed that a high yield

01:11:28 and a complete recycling of nutrients

01:11:30 could be achieved

01:11:31 without the help of chemical products.

01:11:33 In case you were wondering,

01:11:35 it was not the end of the glass complex.

01:11:37 The second mission inside Biosphere 2

01:11:40 took place in March 1994.

01:11:43 Now you can go back to the beginning of the video

01:11:46 to understand how it could have happened for them.

01:11:49 If an asteroid like Apophis hit the Earth,

01:11:52 we would be destroyed.

01:11:54 Huge earthquakes shook the Earth

01:11:58 and tsunamis flooded everything.

01:12:00 Apophis, a celestial body

01:12:03 several billion years old,

01:12:05 has been present in the solar system since its creation.

01:12:08 You are probably wondering

01:12:10 what is the probability that this gigantic rock

01:12:12 will collide with our planet in 2029?

01:12:15 Well, we'll see that, okay?

01:12:18 Apophis is a huge asteroid

01:12:21 discovered in 2004

01:12:23 by the National Kitpik Observatory in Arizona.

01:12:27 Since then,

01:12:28 it is said to be one of the most dangerous asteroids

01:12:31 ever located.

01:12:33 It is about 330 meters wide.

01:12:36 It is a little bigger than the Empire State Building

01:12:38 or the Eiffel Tower.

01:12:40 It is because it is so scary

01:12:42 that it was named Apophis,

01:12:44 after the Egyptian immortal creature

01:12:46 that brought eternal darkness

01:12:48 and destruction.

01:12:50 In 2021,

01:12:53 researchers had the exceptional opportunity

01:12:56 to study this floating rock

01:12:57 when it passed near our planet.

01:12:59 We will come back to this in a minute.

01:13:01 Some scientists say

01:13:03 that there is a 2.7% chance

01:13:05 that Apophis will hit the Earth

01:13:07 on Friday, April 13, 2029.

01:13:09 This would be the Yarkovsky effect

01:13:12 that would be at stake

01:13:14 because it would push this big space rock

01:13:16 towards the Earth.

01:13:18 This effect comes from the unequal emission

01:13:20 of thermal photons,

01:13:22 the result of which is an unimaginable force

01:13:25 exerted on the object hit.

01:13:26 These photons exert a huge thrust

01:13:28 and play an essential role

01:13:30 in the dynamics of the body in question.

01:13:32 The asteroid has two faces,

01:13:35 a dark one and a light one,

01:13:37 just like the Moon.

01:13:39 The light side is facing the Sun

01:13:41 and is warmer than the dark side.

01:13:43 But the object rotates itself

01:13:45 so that its faces constantly change

01:13:47 direction and temperature.

01:13:49 These changes are not good

01:13:51 because they push Apophis slightly towards the Earth.

01:13:54 Unfortunately,

01:13:55 no one knows how the Yarkovsky effect

01:13:57 will influence the trajectory of the asteroid.

01:13:59 On the other hand,

01:14:01 during the last asteroid pass near the Earth in 2021,

01:14:04 astronomers used radars

01:14:06 to take precise measurements of its trajectory

01:14:08 and they were able to conclude

01:14:10 that Apophis will pass at about 3,000 km from the Earth

01:14:12 in 2029

01:14:14 and will not disturb us for at least 100 years.

01:14:16 In general,

01:14:23 every 8,000 years,

01:14:24 our planet is hit by a shooting star

01:14:26 of a similar size to that of Apophis.

01:14:28 The last time we were hit

01:14:31 by a slightly smaller meteor

01:14:33 was in 2013.

01:14:35 A new spacecraft developed by NASA

01:14:40 called Osiris-Rex

01:14:42 was launched in 2016

01:14:44 to collect samples

01:14:46 on another celestial body

01:14:48 slightly less terrifying, Bennu.

01:14:50 Four years later,

01:14:52 the object was targeted,

01:14:53 took some samples,

01:14:55 quickly said goodbye to Bennu

01:14:57 and returned to Earth.

01:14:59 The samples were safely stored

01:15:01 in a capsule deposited in Utah.

01:15:03 So far,

01:15:05 this is the most significant sample

01:15:07 ever taken on an asteroid.

01:15:09 After its delivery,

01:15:11 the ship did not waste time

01:15:13 and went after Apophis.

01:15:15 For this mission,

01:15:17 Osiris-Rex was renamed Osiris-Apex

01:15:19 and it is currently playing chess with Apophis.

01:15:22 With a little luck,

01:15:23 on April 2, 2029,

01:15:25 when the asteroid passes near Earth,

01:15:27 the space probe will reach Apophis

01:15:29 to land there.

01:15:31 It will stay on it for 18 months,

01:15:34 collecting precious information

01:15:36 and taking thousands of photos.

01:15:38 The asteroid will be monitored

01:15:41 with powerful telescopes.

01:15:43 At some point,

01:15:45 Apophis will be too close to the sun

01:15:47 and then Osiris-Apex

01:15:50 will have to watch it.

01:15:51 If you live in Europe,

01:15:53 in West Asia or Africa,

01:15:55 you are one of the lucky ones

01:15:57 who will have the unique opportunity

01:15:59 in a lifetime to see Apophis with the naked eye.

01:16:01 It will be visible in the sky

01:16:04 of these regions in 2029

01:16:06 and those who have telescopes

01:16:08 will be able to see it again in 2036.

01:16:11 Osiris-Apex

01:16:13 will certainly encounter some problems

01:16:15 because the asteroid has a thick crust

01:16:17 and the spacecraft

01:16:19 will not be able to collect data

01:16:20 as easily as on Bennu.

01:16:22 Osiris-Apex has a single propeller

01:16:24 that will blow all the dust of Apophis

01:16:26 when it lands.

01:16:28 It will be a perfect opportunity

01:16:30 to analyze the surface of the asteroid

01:16:32 and see what it is made of.

01:16:34 The probe will spend a year and a half

01:16:36 mapping the asteroid

01:16:38 trying to detect changes in its shape.

01:16:40 All these researches will show

01:16:42 how the celestial body moves

01:16:44 and we will have a better idea

01:16:46 of how to protect our planet

01:16:48 from such objects.

01:16:49 In 2025, NASA will also launch

01:16:51 the Apophis Pathfinder mission

01:16:53 and it will be the first space ship

01:16:55 to ever touch this asteroid.

01:16:57 It will land about a year after its launch.

01:17:00 In addition, NASA has proposed

01:17:02 to send a small-scale test

01:17:04 to allow humanity to develop

01:17:06 effective protection tactics

01:17:08 against asteroid impacts.

01:17:10 We know that Apophis

01:17:12 comes from the main asteroid belt

01:17:14 located between Mars and Jupiter.

01:17:17 Over the last million years,

01:17:18 this celestial body has changed its trajectory

01:17:20 due to the considerable influence

01:17:22 of Jupiter's gravity.

01:17:24 Now, it seems to favor the sun more,

01:17:27 which means that this asteroid

01:17:29 is very close to Earth.

01:17:31 That's why it's ranked among

01:17:33 the celestial bodies near our planet.

01:17:35 Many tests have been carried out

01:17:37 to find a way to deal with these asteroids.

01:17:39 Among the solutions,

01:17:41 there is drilling and detonation

01:17:43 of the inner space body,

01:17:46 as well as new technologies

01:17:47 like attaching rockets

01:17:49 to redirect the harmful object

01:17:51 away from Earth.

01:17:53 We could also hit it

01:17:55 with a powerful enough force

01:17:57 to change its direction.

01:17:59 Apophis is an asteroid of type S

01:18:01 made up of rocks and metals,

01:18:03 iron, nickel, etc.,

01:18:05 and that looks like a peanut.

01:18:07 It can teach us a lot

01:18:09 about the past and also about the future.

01:18:11 The samples collected can reveal

01:18:13 how life on Earth began

01:18:15 and how the Earth was formed.

01:18:16 Many theories suggest

01:18:18 that water came to our planet

01:18:20 thanks to an asteroid or a comet.

01:18:22 Asteroids are like precious time capsules.

01:18:24 Unlike terrestrial rocks,

01:18:26 which have undergone many changes,

01:18:28 like erosion,

01:18:30 most celestial bodies are intact

01:18:32 and much easier to study.

01:18:34 When meteors fall on Earth,

01:18:36 they are covered with debris

01:18:38 that is impossible to clean.

01:18:40 That's why it's so important

01:18:42 to study Apophis right now.

01:18:44 Some asteroids are made of precious metals,

01:18:45 like platinum.

01:18:47 At the moment,

01:18:49 we have a strong demand for metals

01:18:51 for the industry,

01:18:53 and mining on Earth is quite difficult.

01:18:55 A single big meteor

01:18:57 could provide us with iron,

01:18:59 nickel, gold and platinum

01:19:01 for millions of years.

01:19:03 If Apophis contains all these metals,

01:19:05 we will have to break it down

01:19:07 and bring it back to Earth.

01:19:09 A single asteroid could cost billions of dollars.

01:19:11 Space mining

01:19:13 is extremely profitable.

01:19:14 However,

01:19:16 it would cost us more to bring it back to Earth

01:19:18 than to extract its materials here.

01:19:20 With technological progress

01:19:22 and the development of new types of rockets,

01:19:24 it may be possible one day.

01:19:27 So,

01:19:29 even if we have nothing to fear from Apophis

01:19:31 for another hundred years,

01:19:33 we still need to know

01:19:35 what would happen

01:19:37 if such an impact occurred.

01:19:39 Come on, admit it,

01:19:42 you would hear a huge noise

01:19:43 and you would know that a disaster

01:19:45 has happened even from miles away.

01:19:47 You would have to leave your home immediately.

01:19:49 Shortly after the impact,

01:19:51 violent earthquakes would occur

01:19:53 and buildings would fall

01:19:55 as if by themselves.

01:19:57 Staying away from cities

01:19:59 would probably be the best thing to do.

01:20:01 But you would not have to run away by car.

01:20:03 There would be huge traffic jams

01:20:05 and everyone would panic.

01:20:07 Moving by foot or by bike

01:20:09 would be your best option.

01:20:11 A preferred means of transport

01:20:12 would be the plane.

01:20:14 So,

01:20:16 if you have always dreamed of getting

01:20:18 your pilot's license,

01:20:20 you now have a good excuse.

01:20:22 You would also need to have

01:20:24 enough food and drink

01:20:26 and a pair of socks.

01:20:28 Living near the ocean or the sea is pleasant.

01:20:30 But in this scenario,

01:20:32 there would not be a worse place.

01:20:34 Huge waves would hit the coast

01:20:36 after the impact.

01:20:38 Far from the impact area,

01:20:40 it would take up to 30 hours

01:20:41 to reach the coast.

01:20:43 It would take a while to prepare.

01:20:45 The protective shield of our planet

01:20:50 is deteriorating and is no longer enough.

01:20:52 The same goes for our satellites.

01:20:54 First, high-orbit communication satellites

01:20:56 fall to Earth.

01:20:58 Then, low-Earth-orbit astronauts

01:21:00 can no longer contact their control centers.

01:21:03 And finally,

01:21:05 dangerous and relentless cosmic rays

01:21:08 can bombard the entire planet,

01:21:09 causing chaos and devastation.

01:21:11 Are these the terrifying consequences

01:21:13 of the reversal of the magnetic field of the planet

01:21:15 that we will have to face?

01:21:17 At the moment,

01:21:19 while you are watching this video,

01:21:21 the magnetic pole north of the Earth

01:21:23 is extremely unbalanced.

01:21:25 It is so serious that scientists

01:21:27 will have to revise the global model

01:21:29 of the magnetic field

01:21:31 that was published only 4 years ago.

01:21:33 Does this mean that the magnetic pole

01:21:35 of our planet will soon reverse?

01:21:37 We will discover it a little later.

01:21:38 You see, the magnetic pole

01:21:40 moves quite erratically

01:21:42 from the Canadian Arctic to Siberia.

01:21:44 And these movements are very unpredictable.

01:21:46 But it is normal for the pole to move.

01:21:49 There are long-term surveys

01:21:51 in London and Paris

01:21:53 that prove that the magnetic pole north

01:21:55 moves randomly around the rotation pole

01:21:57 over periods of several hundred years.

01:22:00 But the most amazing thing about its movement

01:22:06 is that it tends to gain speed.

01:22:07 Around the mid-1990s,

01:22:09 the magnetic pole has unobtrusively accelerated,

01:22:12 going from a little over 14 km

01:22:14 to 54 km per year.

01:22:16 And recently, the pole has crossed

01:22:18 the date line,

01:22:20 heading towards the eastern hemisphere.

01:22:22 The European Space Agency

01:22:24 launched satellites

01:22:26 to analyze the magnetic field in 2013.

01:22:28 Thanks to them,

01:22:30 researchers have precious data

01:22:32 that they can not only use

01:22:35 to study the magnetic field,

01:22:36 but also to update them

01:22:38 every 6 to 12 months.

01:22:40 This is how they noticed

01:22:42 that the main field was getting smaller,

01:22:44 it could be a sign

01:22:46 that the magnetic field of the planet

01:22:48 is about to reverse.

01:22:50 To better understand this process,

01:22:52 we must understand how the field

01:22:54 emanating from our core works.

01:22:56 Let's say we have a magnetized bar

01:22:58 that crosses the center of our planet

01:23:00 and is a north pole and a south pole.

01:23:02 This magnet is incredibly powerful,

01:23:04 it can change the magnitude

01:23:05 of the magnetic field of our planet to the surface.

01:23:07 Our magnet not only moves,

01:23:09 but it also weakens,

01:23:11 by about 7% every century.

01:23:13 It must be admitted

01:23:15 that this magnet is not a perfect representation

01:23:17 of the field produced by our core.

01:23:19 It is rather as if electric currents

01:23:21 generated the magnetic field of the Earth.

01:23:23 Nevertheless,

01:23:25 this model facilitates the understanding

01:23:27 of what is happening to our planet at the moment.

01:23:29 The magnetic field of our planet

01:23:31 plays an important role

01:23:33 in the detection of dangerous radiation

01:23:34 and geomagnetic activity,

01:23:36 which is the product of the interaction

01:23:38 between solar wind and the Earth's magnetosphere.

01:23:40 The magnetic field of the Earth

01:23:42 also moves.

01:23:44 Scientists have studied

01:23:46 and followed the movement of magnetic poles

01:23:48 over hundreds of years.

01:23:50 The historical movements of these poles

01:23:52 indicate changes in the global geometry

01:23:54 of the magnetic field of our planet.

01:23:56 And they can also indicate

01:23:58 the beginning of the field's inversion.

01:24:00 This is what is called

01:24:02 a shift between the north and south magnetic poles.

01:24:03 It should be noted that if the north magnetic pole

01:24:09 moves a little,

01:24:11 it is not a very big problem.

01:24:13 But a complete inversion

01:24:15 could have a serious impact

01:24:17 on the climate of our planet

01:24:19 as well as on our modern technologies.

01:24:21 Fortunately, such inversions

01:24:23 do not occur overnight.

01:24:25 The whole process extends over thousands of years.

01:24:27 In addition,

01:24:29 even if the magnetic pole weakens

01:24:31 it does not disappear completely.

01:24:32 Thus, the terrible events

01:24:34 of the beginning of this video

01:24:36 are unlikely to happen to us.

01:24:38 The magnetosphere will continue

01:24:40 to protect the planet from cosmic rays

01:24:42 and charged solar particles,

01:24:44 even if a certain amount of particular radiation

01:24:46 could still reach the Earth's surface.

01:24:48 Magnetic fields are generated

01:24:50 by electric charges in motion.

01:24:52 If a material allows these charges

01:24:54 to move easily in it,

01:24:56 it is called a conductor.

01:24:58 Metal is an excellent conductor

01:25:00 and we often use it

01:25:01 to transfer electric currents

01:25:03 from one place to another.

01:25:05 In this case,

01:25:07 the electric current is made up of negative charges

01:25:09 called electrons moving through the metal.

01:25:11 It is this current that generates a magnetic field.

01:25:13 The Earth has a liquid iron core.

01:25:15 In other words,

01:25:17 there are layers and layers of conductive materials

01:25:19 inside our planet.

01:25:21 The charge currents

01:25:23 constantly move through the core

01:25:25 and the liquid metal also circulates there,

01:25:27 generating the magnetic field.

01:25:30 This magnetic field

01:25:31 produces something

01:25:33 that looks like a bubble around the planet.

01:25:35 It is called the magnetosphere

01:25:37 and it is located

01:25:39 above the highest part of the atmosphere.

01:25:41 This layer protects us

01:25:43 and deflects the cosmic radiation

01:25:45 of high energy

01:25:47 that would otherwise be extremely dangerous

01:25:49 for people and other forms of life on Earth.

01:25:51 The magnetosphere also interacts

01:25:53 with the ionosphere.

01:25:55 The layer of the atmosphere of our planet

01:25:58 contains tons of free ions and electrons

01:25:59 and is able to reflect radio waves.

01:26:01 The interaction between these two layers

01:26:03 and the magnetized solar wind

01:26:05 is what scientists call

01:26:07 the space weather.

01:26:09 The solar wind is normally quite light

01:26:11 and there is absolutely no space weather.

01:26:13 But sometimes,

01:26:16 the sun begins to eject

01:26:18 huge clouds of magnetized gas

01:26:20 that can reach incredible speeds.

01:26:22 They are called coronal mass ejections

01:26:24 or EMC.

01:26:27 These are ejected from the sun

01:26:28 over several hours.

01:26:30 EMCs are generally similar

01:26:32 to huge twisted filaments

01:26:34 and can occur spontaneously.

01:26:36 Their frequency varies

01:26:38 according to a 11-year solar cycle.

01:26:40 For example, at the minimum solar,

01:26:42 one can observe an ejection per day.

01:26:44 And when the sun is in its most active phase,

01:26:46 there can be up to 3 EMCs per day.

01:26:48 Coronal mass ejections

01:26:50 disturb the calm flow of the solar wind

01:26:52 and cause serious disturbances

01:26:54 capable of damaging things

01:26:56 like the Earth's satellites

01:26:57 and the planet's surface.

01:26:59 If coronal mass ejections

01:27:01 reach the Earth,

01:27:03 their interaction with the magnetosphere

01:27:05 generates geomagnetic storms.

01:27:07 These can produce auroras

01:27:09 that occur when a flow of charged particles

01:27:11 hits the atmosphere and illuminates it.

01:27:13 And then there are also solar eruptions.

01:27:15 They develop more rapidly

01:27:17 and with much more energy

01:27:19 than coronal mass ejections.

01:27:21 Solar eruptions often occur

01:27:23 shortly after coronal mass ejections.

01:27:25 The most powerful volcanic eruptions

01:27:26 are not so powerful

01:27:28 compared to solar eruptions

01:27:30 that release 10 million times more energy.

01:27:32 In a few minutes,

01:27:34 a solar eruption can emit

01:27:36 billions of tons of charged particles.

01:27:38 Solar eruptions are also incredibly hot

01:27:40 with temperatures reaching

01:27:42 several million degrees.

01:27:44 Astronomers think

01:27:47 that such solar explosions

01:27:49 occur in the middle of the night

01:27:51 and in the middle of the day.

01:27:54 These solar explosions occur

01:27:55 when the magnetic field of the sun

01:27:57 twists in certain regions.

01:27:59 At some point,

01:28:01 all the stored energy is released.

01:28:03 The star emits light and particles,

01:28:05 mainly electrons and protons.

01:28:07 Most solar eruptions

01:28:09 last a few minutes,

01:28:11 but some last for hours.

01:28:13 A powerful solar storm

01:28:15 can potentially cause

01:28:17 a devastating power outage

01:28:19 on the entire Earth.

01:28:21 If it weren't for the Earth's magnetosphere,

01:28:23 it would be devastating.

01:28:24 Fortunately, it deflects most of the solar particles

01:28:26 that rush to our planet

01:28:28 from our star

01:28:30 at a speed of more than 1.6 million km/h.

01:28:32 But even so,

01:28:34 during space weather events,

01:28:36 there is a lot of dangerous radiation

01:28:38 near the Earth.

01:28:40 It can potentially harm astronauts

01:28:42 and space engines.

01:28:44 In addition,

01:28:46 the space weather can damage

01:28:48 our major driving systems,

01:28:50 such as pipelines and electrical networks,

01:28:52 and other infrastructure.

01:28:53 Scientists map

01:28:55 and regularly monitor

01:28:57 the orientation and global shape

01:28:59 of our planet's magnetic field.

01:29:01 To do this,

01:29:03 they use local measurements

01:29:05 of the orientation and amplitude of the field.

01:29:07 This is how they were able to conclude

01:29:09 that the location of the North Magnetic Pole

01:29:11 had moved almost 1,000 km

01:29:13 since the first measurements

01:29:15 were taken in 1831.

01:29:17 The magnetic field of our planet

01:29:20 varies from 100,000 to 1 million years.

01:29:22 We can say how often this happens

01:29:24 by looking at the volcanic rocks

01:29:26 at the bottom of the ocean.

01:29:28 They retain the orientation

01:29:30 and strength of the Earth's magnetic field

01:29:32 at the time of their creation.

01:29:34 Thus, the dating of these rocks

01:29:36 gives us an image of the evolution

01:29:38 of the magnetic field of our planet

01:29:40 over time.

01:29:42 From a geological point of view,

01:29:45 field inversions occur quite rapidly.

01:29:47 But they are extremely fast

01:29:49 from a human point of view.

01:29:50 A complete inversion

01:29:52 normally takes a few thousand years.

01:29:54 But during this period,

01:29:56 the orientation of the magnetosphere can change,

01:29:58 exposing the Earth

01:30:00 to more cosmic radiation.

01:30:02 Such events tend to modify

01:30:04 the concentration of ozone in the atmosphere.

01:30:06 In any case,

01:30:08 scientists cannot say with certainty

01:30:10 when the next magnetic field inversion

01:30:12 will take place.

01:30:14 But they continue to map

01:30:16 and monitor the movement

01:30:18 of magnetic gold on our planet.

01:30:19 In fact, the Earth is not the only planet

01:30:21 with a magnetic field.

01:30:23 Gas giants like Jupiter

01:30:25 also have a layer of conductive metallic hydrogen

01:30:27 that generates their magnetic field.

01:30:29 Jupiter's internal field

01:30:31 prevents the solar wind from interacting directly

01:30:33 with the planet's atmosphere.

01:30:35 If one of the many possible apocalyptic scenarios

01:30:42 comes true

01:30:44 and humanity is eradicated,

01:30:47 a black box will tell those who will come

01:30:48 after what led us to our end.

01:30:50 This strong 10-meter-long chamber

01:30:53 located in a region

01:30:55 far from the west of Tasmania

01:30:57 is supposed to document all the mistakes

01:30:59 that humanity has made

01:31:01 and which have caused the apocalypse.

01:31:03 Artists, architects and researchers

01:31:05 at the origin of the black box of the Earth

01:31:07 think that this reinforced steel-made installation

01:31:09 will resist fire, water

01:31:11 and all other natural disasters.

01:31:13 But it is not so.

01:31:16 Unless, of course,

01:31:17 the planet is completely destroyed.

01:31:19 Just like the black boxes

01:31:22 that we find in airplanes,

01:31:24 this time capsule is supposed to help

01:31:26 the civilization that will follow ours

01:31:28 to avoid the tragic fate of our humanity.

01:31:30 The project is entirely non-commercial

01:31:34 and carries an important message.

01:31:36 The box will be filled with storage disks

01:31:38 and will be connected to the Internet.

01:31:40 Solar panels on the roof

01:31:42 will feed it in a way

01:31:45 that the stars will feed it in electricity

01:31:46 and batteries will ensure

01:31:48 the storage of a life-saving energy.

01:31:50 Every time the sun shines in the sky,

01:31:52 the black box will update its scientific data.

01:31:54 An algorithm will sort these data

01:31:56 in order to save only the relevant information

01:31:58 for the project.

01:32:00 We will measure the terrestrial and marine temperatures,

01:32:02 the acidification of the oceans,

01:32:04 the extinction of species,

01:32:06 the use of land,

01:32:08 as well as the human demography

01:32:10 and the consumption of energy.

01:32:12 Among the secondary data,

01:32:14 we will find newspaper titles,

01:32:15 social media posts

01:32:17 and news on the main events

01:32:19 concerning the environment.

01:32:21 The creators of the box decided to code it

01:32:24 and store their data in different formats,

01:32:26 including binary code.

01:32:28 Instructions on how to retrieve

01:32:31 all this precious information

01:32:33 will be engraved on the outside of the box.

01:32:35 Some of the biggest brains

01:32:39 working on this project

01:32:41 fear that this may make some people

01:32:43 curious and force the box

01:32:44 long before it is time to do so.

01:32:46 The hard disk powered by solar energy

01:32:48 will have enough space

01:32:50 to collect data for 50 years.

01:32:52 The most pessimistic scientific models

01:32:55 do not predict the end of the world

01:32:57 before this date.

01:32:59 This great misfortune

01:33:01 may not even happen in centuries.

01:33:03 The idea of a box that records

01:33:06 everything that happens

01:33:08 before an air crash

01:33:10 was born in the middle of the 20th century.

01:33:13 At that time,

01:33:14 the first jet in the world,

01:33:16 the De Havilland's Comet,

01:33:18 crashed 7 times in 2 years,

01:33:20 killing 110 people.

01:33:22 The Australian Civil Aviation Department

01:33:26 wanted to know what caused these accidents.

01:33:29 Among the experts,

01:33:33 there was Dr. David Warren,

01:33:35 a chemist specializing in fuels.

01:33:37 He realized that we simply did not have

01:33:39 enough data to draw conclusions.

01:33:42 There was no one to say

01:33:43 what had happened before the accident.

01:33:45 He remembered seeing a recorder

01:33:47 recording sound on a steel wire

01:33:49 at a commercial fair.

01:33:51 So, he wrote to his superior

01:33:53 to suggest that he design

01:33:55 a voice recorder

01:33:57 that would follow what was happening

01:33:59 in the cockpit.

01:34:01 The flight data would also be recorded

01:34:03 and stored in an unbreakable box.

01:34:05 Aviation was not very important

01:34:07 in Australia at that time.

01:34:10 So, the idea did not interest

01:34:11 the superior in question.

01:34:13 But Warren still began to work

01:34:15 on a prototype in his garage.

01:34:17 He showed his device

01:34:20 to the secretary of the British Air

01:34:22 Registration Board,

01:34:24 passing through Australia.

01:34:26 And he loved the idea.

01:34:28 Soon, Dr. Warren was able to

01:34:30 form a whole team to help him

01:34:32 develop a pre-production prototype.

01:34:34 His invention does not actually

01:34:36 bear the name of "black box",

01:34:39 but of "flight recorder".

01:34:40 And it is orange, not black.

01:34:42 We probably say that it is black

01:34:45 because it takes this color

01:34:47 after an accident.

01:34:49 Or maybe because the first boxes

01:34:51 were painted like this

01:34:53 to avoid solar reflection.

01:34:55 Or because it is the name

01:34:57 that scientists give to devices

01:34:59 with input and output data

01:35:01 and complex internal functioning.

01:35:03 So, the flight recorder

01:35:05 is made up of two parts.

01:35:08 A data recorder

01:35:09 and a vocal recorder.

01:35:11 Historically,

01:35:13 it was two boxes.

01:35:15 But now, it is two cylinders.

01:35:17 The data recorder

01:35:19 keeps the flight parameters.

01:35:21 The exhaust gas,

01:35:23 the temperature,

01:35:25 the fuel flow,

01:35:27 the speed,

01:35:29 the altitude,

01:35:31 and the descent rate.

01:35:33 The second cylinder

01:35:35 records the sounds in the cockpit

01:35:37 and the flight parameters.

01:35:38 Sometimes,

01:35:40 the two parts are combined

01:35:42 and it looks like a box.

01:35:44 The box records the data

01:35:46 and the voices in the cockpit.

01:35:48 But it is actually

01:35:50 placed at the back of the plane

01:35:52 where the structure of the device

01:35:54 will protect them in case of an accident.

01:35:56 The black box has a locating beacon

01:35:58 that is activated when in contact with water.

01:36:00 It emits a signal for 30 days.

01:36:02 The bright orange color of the recorder

01:36:04 allows the research teams

01:36:06 to locate it more easily.

01:36:07 Sometimes,

01:36:09 it takes a lot of time

01:36:11 to find a box.

01:36:13 And in some cases,

01:36:15 we never find it.

01:36:17 Long before the invention of the first plane,

01:36:19 there was a black box

01:36:21 with a universal range.

01:36:23 The old library of Alexandria.

01:36:25 In Antiquity,

01:36:27 people in Egypt,

01:36:29 Mesopotamia and Greece

01:36:31 were familiar with libraries and archives.

01:36:33 But these first institutions

01:36:35 were mainly intended

01:36:36 to preserve traditions and heritage.

01:36:38 The concept of a universal library

01:36:40 only became a reality

01:36:42 when the Greeks started to think big.

01:36:44 They were so impressed

01:36:46 by what their neighbors were doing in Egypt

01:36:48 that they organized expeditions

01:36:50 to acquire knowledge.

01:36:52 Alexander the Great,

01:36:54 king of Macedonia,

01:36:56 seeing this new thirst for knowledge,

01:36:58 demanded of his companions,

01:37:00 generals and scholars

01:37:02 to bring him everything he could learn

01:37:04 about the history of the city

01:37:05 and the history of the city.

01:37:07 This allowed them to gather

01:37:09 a lot of information about the geography

01:37:11 and contributed to the creation

01:37:13 of a huge library.

01:37:15 Most of the information

01:37:17 was written in Greek.

01:37:19 For example,

01:37:21 Aristotle's writings were found

01:37:23 in the corpus of literature.

01:37:25 According to some sources,

01:37:27 during this book hunt,

01:37:29 the founders of the library

01:37:32 were given a huge compensation.

01:37:33 If they decided that a book

01:37:35 was precious,

01:37:37 they made a copy of it

01:37:39 and gave it to its owner

01:37:41 with a compensation.

01:37:43 The original remained in the library.

01:37:45 Another story tells us

01:37:47 that Ptolemy III,

01:37:49 the son of the founder of the library,

01:37:51 offered the governors of Athens

01:37:53 a huge compensation

01:37:55 for the right to copy the texts

01:37:57 of the greatest poets.

01:37:59 He kept the originals

01:38:01 and burned all his knowledge

01:38:02 without thinking that it would

01:38:04 lead to their own loss.

01:38:06 There was then no way

01:38:08 to disseminate the information.

01:38:10 Only one source held

01:38:12 most of the knowledge

01:38:14 that humanity had accumulated.

01:38:16 The great minds

01:38:18 were not content to fill it.

01:38:20 They also created important

01:38:22 correspondences between the works,

01:38:24 taking the best part

01:38:26 of the library.

01:38:28 If Alexandri's library

01:38:30 had been a library,

01:38:31 it would have been a library

01:38:33 of the great minds

01:38:35 who had been

01:38:37 the great minds

01:38:39 of the world.

01:38:41 The library

01:38:43 was a library

01:38:45 of the great minds

01:38:47 who had been

01:38:49 the great minds

01:38:51 of the world.

01:38:53 The library

01:38:55 was a library

01:38:57 of the great minds

01:38:59 who had been

01:39:00 the great minds

01:39:02 of the world.

01:39:04 The library

01:39:06 was a library

01:39:08 of the great minds

01:39:10 who had been

01:39:12 the great minds

01:39:14 of the world.

01:39:16 The library

01:39:18 was a library

01:39:20 of the great minds

01:39:22 who had been

01:39:24 the great minds

01:39:26 of the world.

01:39:28 If the knowledge

01:39:29 of the great minds

01:39:31 had been lost,

01:39:33 we would not lose an empire,

01:39:35 but the whole world.

01:39:37 Ladies and gentlemen,

01:39:39 this is your captain speaking.

01:39:41 We will be ready to take off

01:39:43 in 3,

01:39:45 2,

01:39:47 1.

01:39:48 Living in a spaceship

01:39:50 is like the dream subject

01:39:52 of a science fiction movie,

01:39:54 but it is gradually becoming more and more

01:39:57 realistic.

01:39:58 On Earth,

01:40:00 thanks to the atmosphere,

01:40:02 the sky scatters the light of the sun.

01:40:04 We receive light from different directions.

01:40:06 There are then shadows,

01:40:08 contrast and ambient light.

01:40:10 In a spaceship, however,

01:40:12 there is no sky to create

01:40:14 this ambience light.

01:40:16 When you are in a spaceship

01:40:18 inside the solar system,

01:40:20 one side of the ship can be lit

01:40:22 by the sun

01:40:24 or another star,

01:40:26 if your spaceship manages

01:40:27 to move away from the entire solar system,

01:40:29 you may have to say goodbye

01:40:31 to the illuminated side of the ship.

01:40:33 You will be very far from any star

01:40:35 and the ship will therefore fly

01:40:37 in the most total darkness.

01:40:39 But do not worry,

01:40:41 our cutting-edge technologies

01:40:43 will probably find a way

01:40:45 to imitate the light of the sun.

01:40:47 The designers may place

01:40:49 LED light panels similar to windows

01:40:51 and the inhabitants of the ship

01:40:53 will not see much difference.

01:40:55 A study has revealed

01:40:56 that a crew of 160 people

01:40:58 could make up a viable population

01:41:00 for about 200 years.

01:41:02 The important thing is to select

01:41:04 the crew members

01:41:06 from a large genetic pool.

01:41:08 No passenger should be closer

01:41:10 than cousins in the 6th or 7th degree.

01:41:12 This is a projection of our time.

01:41:14 But who knows,

01:41:16 maybe hundreds of years later,

01:41:18 entire countries will live

01:41:20 in the same spaceship.

01:41:22 Your neighbor on Earth

01:41:24 reminds me of Thor's scene

01:41:25 Ragnarok where Asgardians

01:41:27 who survived Aela

01:41:29 escape with the Grand Master's ship

01:41:31 and go back to Earth to settle there.

01:41:33 Maybe we will go to Proxima Centauri B.

01:41:36 It is an exoplanet,

01:41:38 the term used to define planets

01:41:40 located beyond our solar system.

01:41:43 Proxima B is in another stellar system

01:41:45 and some scientists think

01:41:47 it has potential.

01:41:49 It is thought that it is possible

01:41:51 that liquid water exists on its surface.

01:41:53 It is important because this planet

01:41:54 is our nearest neighboring exoplanet.

01:41:57 Yes, the closest.

01:41:59 But it is located

01:42:01 about 40 billion kilometers from us.

01:42:03 To better understand this proximity,

01:42:05 we will give you a comparison.

01:42:07 Currently, one of our fastest spaceships,

01:42:09 namely New Horizons,

01:42:11 reaches a dizzying speed

01:42:13 of more than 50,000 km / h.

01:42:15 But even with this speed,

01:42:17 it would take him thousands of years

01:42:19 to reach Proxima B.

01:42:22 We will find out how to distort

01:42:23 the space-time equation by then.

01:42:25 Being realistic,

01:42:27 this is the first option that seems most likely.

01:42:29 Suppose we make the trip

01:42:31 with our fastest spaceships.

01:42:33 It would still be a trip

01:42:35 of a few hundred years.

01:42:37 This brings us to another minor problem,

01:42:39 the life span of humans.

01:42:41 A single crew

01:42:43 will not be able to go to the end of the trip.

01:42:45 Here, generational ships

01:42:47 are a solution.

01:42:49 An adult community enters the ship,

01:42:51 then their children,

01:42:52 and the children of their children,

01:42:54 until humanity finally reaches

01:42:56 the new planet.

01:42:58 There are two other solutions.

01:43:00 If researchers managed to make people live

01:43:02 for centuries,

01:43:04 we would not need these generational ships.

01:43:06 Likewise,

01:43:08 there could be a system

01:43:10 that allows people to freeze.

01:43:12 It will take 20,000 people

01:43:14 to start a healthy population

01:43:16 on a new planet.

01:43:18 For now,

01:43:20 the encounters would not be as romantic

01:43:21 as on Earth.

01:43:23 There will probably be a geneticist

01:43:25 who will regulate our reproduction.

01:43:27 Freedom of choice, in general,

01:43:29 would be reduced.

01:43:31 The rules will be strict.

01:43:33 In each generation,

01:43:35 there will be certain tasks to manage.

01:43:37 Someone will have to be a doctor,

01:43:39 and someone else will have to be a plumber.

01:43:41 The new generations could be subjected

01:43:43 to career planning tests.

01:43:45 Everyone would see themselves assigned

01:43:47 a profession according to their merits,

01:43:49 their passions,

01:43:50 and the jobs available.

01:43:52 It reminds me a bit of Snowpiercer,

01:43:54 but with a little luck,

01:43:56 things would happen more humanly

01:43:58 in this version.

01:44:00 People all need water,

01:44:02 and they will create waste.

01:44:04 By then,

01:44:06 we may no longer depend on plastic.

01:44:08 In addition, recycling may be done

01:44:10 at a different level.

01:44:12 Yet, we will need water.

01:44:14 A healthy human being

01:44:16 needs about 1,200 liters of water per year.

01:44:18 It's not like they stopped on a planet

01:44:19 to fill their water tank.

01:44:21 How can the inhabitants of space ships

01:44:23 solve such a problem?

01:44:25 Well,

01:44:27 there are already systems

01:44:29 that recycle the waste of astronauts

01:44:31 in fresh water.

01:44:33 The next problem is that of the infirmary.

01:44:35 A space ship can contain

01:44:37 virtually no bacteria or microbes,

01:44:39 but people need it

01:44:41 to strengthen their immune system.

01:44:43 If they are too confined

01:44:45 and land on a foreign planet,

01:44:47 they will face potential conditions

01:44:48 that will reign there.

01:44:50 Armament is also important.

01:44:52 The space is far away and highly radioactive.

01:44:55 Our planet has a magnetic field

01:44:57 that protects us from these waves

01:44:59 that grill DNA.

01:45:01 Outside,

01:45:03 the space ship will need a solid shield.

01:45:05 Maybe we can create

01:45:07 a kind of field of force?

01:45:09 NASA is working on systems

01:45:11 that allow plants to grow in space.

01:45:13 We will probably see special sections

01:45:16 dedicated to agriculture and breeding.

01:45:17 I have the impression

01:45:19 that this type of ship

01:45:21 would also carry samples of flora and fauna.

01:45:23 Who knows,

01:45:25 there may be specific parks

01:45:27 and different mini-ecosystems.

01:45:29 It would be excellent

01:45:31 for the mental health of the people on board the ship.

01:45:33 It is good to preserve the existence

01:45:35 of the human race,

01:45:37 but existential crises

01:45:39 can disturb passengers.

01:45:41 They could eat their space sandwich

01:45:43 in the park

01:45:45 to the sound of the birds' chirping.

01:45:46 Not just a garden,

01:45:48 but the youngest passengers

01:45:50 could need a playground

01:45:52 and a school,

01:45:54 in this case, a cabin,

01:45:56 to study.

01:45:58 They will probably have

01:46:00 a new school program.

01:46:02 How to stay alive on a foreign planet

01:46:04 level CE1?

01:46:06 By the time we have such a ship,

01:46:08 high-tech AI and robots

01:46:10 will probably be more in vogue than ever.

01:46:12 There could be robots

01:46:14 that can replicate themselves.

01:46:15 We can send these robots

01:46:17 to our new potential planet in advance,

01:46:19 and then see what happens.

01:46:21 We can even send

01:46:23 teams of robots

01:46:25 to several planets

01:46:27 and see which one has the best habitat.

01:46:29 I admit it,

01:46:31 generational ships look like an idea

01:46:33 taken from Hollywood superproductions,

01:46:35 but there is an initiative

01:46:37 called the 100-Year Starship Project.

01:46:39 Mark Millis,

01:46:41 founder of the ToeZero Foundation,

01:46:43 and his team

01:46:44 designed a probe called Icarus.

01:46:46 It has the theoretical ability

01:46:48 to accelerate up to a tenth

01:46:50 or a fifth of the speed of light.

01:46:52 Although the current design of Icarus

01:46:54 is not particularly elegant,

01:46:56 as it looks like a mastodon

01:46:58 the size of a skyscraper

01:47:00 mainly composed of rows

01:47:02 and stacks of spherical fuel tanks,

01:47:04 Millis explains that

01:47:06 it is not a definitive representation

01:47:08 of what an interstellar ship

01:47:10 could look like,

01:47:12 but rather of the most logical design

01:47:13 at first.

01:47:15 When it comes to designing

01:47:17 space ships for humans,

01:47:19 gravity is a key element

01:47:21 to take into account

01:47:23 to prevent the erosion

01:47:25 of bone and muscle density.

01:47:27 The solution is to generate gravity

01:47:29 with a rotating cabin

01:47:31 or centrifuge,

01:47:33 but it must be large enough

01:47:35 to permanently simulate

01:47:37 terrestrial gravity

01:47:39 to avoid disorientation

01:47:41 and to avoid

01:47:42 the possibility of a collision.

01:47:44 The crew and passengers

01:47:46 must be prepared

01:47:48 for different scenarios.

01:47:50 They must have equipment

01:47:52 to scan the territory,

01:47:54 or even self-defense weapons

01:47:56 to protect themselves

01:47:58 from potentially hostile life forms.

01:48:00 Once they have arrived at Bonport,

01:48:02 they will also need tools

01:48:04 to build their new home

01:48:06 when they finally arrive

01:48:08 on their new planet.

01:48:10 The crew will also like

01:48:11 to implement advanced technology

01:48:13 to get around the planets.

01:48:15 "Hi mom,

01:48:17 I brought you a rock

01:48:19 as a souvenir of the surface of Mars.

01:48:21 New professions could appear

01:48:23 as a space travel guide live

01:48:25 and we could need

01:48:27 a type of document,

01:48:29 like a visa,

01:48:31 to visit other habitable planets.

01:48:33 A meteor shower is expected,

01:48:35 so stay in your base

01:48:37 for the next two years,"

01:48:39 "Ok, I'll calm down."

01:48:40 So, how would you imagine

01:48:42 a ship capable of transporting

01:48:44 humans from one solar system to another?

01:48:46 Would it have wings

01:48:48 or would it look like a rocket?

01:48:50 Tell us more about the look

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