Plongez dans les mystères du cosmos avec notre dernière vidéo, abordant la question intrigante : "Que se passe-t-il lorsque vous rencontrez un trou noir ?" Découvrez des faits stupéfiants sur ces géants cosmiques et d'autres phénomènes étonnants. Rejoignez-nous pour une exploration captivante des secrets les plus énigmatiques de l'univers ! #TrouNoir Animation créée par Sympa.
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Musique par Epidemic Sound https://www.epidemicsound.com
Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna
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Nos réseaux sociaux :
Facebook: https://www.facebook.com/sympasympacom/
Instagram: https://www.instagram.com/sympa.officiel/
Stock de fichiers (photos, vidéos et autres):
https://www.depositphotos.com
https://www.shutterstock.com
https://www.eastnews.ru
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Si tu en veux encore plus, fais un tour ici:
http://sympa-sympa.com
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FunTranscript
00:00 Dark monsters, always hungry, live everywhere in the universe.
00:06 They are born when massive stars explode in space.
00:10 Some black holes, as heavy as the Earth, are not bigger than a ping-pong ball.
00:15 They have no surface, but their gravity is so strong that even light cannot escape.
00:21 Black holes also have no physical limits, like a membrane.
00:24 The horizon of events, which is the closest to a limit in the conventional sense, is a threshold that marks the point of no return.
00:32 For a star, the encounter with a black hole usually ends in a light show and its destruction.
00:39 To the knowledge of astronomers, a single star managed to survive a meeting with a black hole as heavy as 400,000 suns.
00:47 This happened in a galaxy located about 250 million light years from Earth.
00:53 Astronomers equipped with very powerful devices noticed X-ray bursts that raged in space every 9 hours.
01:01 They thought they were call signals for a star trapped by a cosmic abyss.
01:06 The star was a red lambda giant when it met its new friend for the first time.
01:12 When they got closer, the hungry space monster could not resist the temptation and gnawed at its guest.
01:19 When it ran out of the outer layers of hydrogen from the star, all that remained was the heart.
01:25 Finally, the poor thing turned into a white dwarf, but for some obscure reason,
01:30 the giant monster could not finish its meal and trapped it in its orbit for later.
01:35 Since then, the white dwarf has been traveling in an orbit of 9 hours.
01:39 It stays far enough from the hole not to fall into it or be swallowed.
01:44 But its journey is not easy. Because of gravity, its orbital trajectory is constantly deviated.
01:50 After two days, it looks like a spiral pattern.
01:54 As the black hole keeps twitching, the star continues to lose its mass and grow in size.
02:00 Its own orbit becomes more and more circular.
02:03 Scientists think that one day, it will be able to spiral away from its bad friend
02:08 and turn into a planet the size of Jupiter in a billion years.
02:12 That's 70 times more than the current age of the universe.
02:15 So it could never happen.
02:18 The Milky Way alone has hundreds of millions of black holes, and there are many more beyond.
02:24 It could feed on other stars and release them into other galaxies.
02:28 The telescopes that currently exist may not be powerful enough to spot them,
02:33 but most galaxies, including our Milky Way, have supermassive black holes in their center.
02:39 They can be billions of times heavier than the Sun.
02:42 Others of their kind have only three times the mass of the Sun.
02:46 The closest black hole to Earth has been spotted 1,000 light years away,
02:50 that is, very close in galactic terms.
02:52 It is in a stellar system that you can see with the naked eye.
02:56 Scientists discovered it when they noticed that a star was behaving strangely.
03:00 It was a giant that was spinning wildly.
03:03 They guessed it must have a powerful gravitational companion.
03:07 The most famous black hole that astronomers have spotted so far
03:11 weighs as much as 34 billion suns,
03:14 and is about 8,000 times larger than the one in the center of the Milky Way.
03:19 It eats the equivalent of one sun a day.
03:22 Sometimes, some black holes even devour others that are too close to them.
03:27 Before you decide to get on a spaceship to escape to a safe and unblackened galaxy,
03:32 here are some good news.
03:34 Even though they are supermassive, they do not have a large enough radius to destroy Earth.
03:39 And even the most famed of them are safe if you observe them from afar.
03:43 No black hole should get closer to our planet than the Sun,
03:47 for an equal duration of 10 billion times the current age of the universe.
03:52 In the unlikely case that one of these frightening things would pass near Neptune,
03:56 it could still affect the Earth's orbit, which would not be good.
04:00 In theory, anything can turn into a black hole.
04:04 The only difference between a black hole and the Sun is the material its center is made of.
04:09 It is incredibly dense in these monsters of space.
04:12 In reality, there is only one known way to create a black hole.
04:16 A supermassive star's gravitational collapse is needed,
04:19 of 20 to 30 times the mass of the Sun.
04:22 Thus, the Sun will never turn into a black hole.
04:27 But if this were to happen, and the old star retained its mass,
04:30 it would still have the same gravitational power.
04:33 The Earth would continue to rotate around it and would not be attracted.
04:37 Its orbit would also remain identical.
04:40 The only huge problem would be the lack of solar light.
04:44 In reality, the Sun is not massive enough for such a transformation,
04:48 and would eventually become a white dwarf.
04:51 A black hole will never eat an entire galaxy for its breakfast.
04:55 There are about 400 billion stars in the Milky Way.
04:58 But only 0.1% of all the stars that form will eventually become black holes.
05:04 The perpetually starved supermassive monster,
05:07 which is located in the middle of a galaxy,
05:09 has an impressive gravitational range.
05:12 But even that would not be enough.
05:14 It has already eaten most of the stars that were close to it.
05:17 It already weighs the equivalent of several million suns,
05:20 so that it cannot grow much more,
05:23 even if it continues to gnaw at stars that look like suns.
05:27 The galaxies will continue to hit each other,
05:30 and the black holes will grow and fuse.
05:32 But since the universe is already huge, and it continues to expand,
05:36 these collisions and fusions will not last forever.
05:39 The black holes will travel in this immense space like wandering stars.
05:43 They will not even be able to eat the black matter at the periphery of the galaxies.
05:48 In the end, all black holes will perish, but this will happen in a very, very long time.
05:54 If you one day become a space explorer,
05:56 and you travel far enough to meet a black hole and fall into it,
06:00 your life will not stop instantly.
06:03 On the contrary, things will be much more complicated.
06:06 The way you perceive space and time will change,
06:09 and your reality will be divided in two.
06:12 In one of them, you will cease to exist.
06:14 In the other, you will live and enter the hole without being hurt.
06:18 When you go deeper into the hole,
06:21 you will notice that space is becoming more and more curved.
06:24 In the center of the hole, it is infinitely curved.
06:27 This is what is called singularity.
06:30 The laws of physics based on the principles of space and time do not run here.
06:34 In a sufficiently large hole, millions of times larger than the sun,
06:38 everything would go perfectly well for you,
06:40 and you would continue to fall freefall without feeling any gravity.
06:45 You could simply keep falling into total vacuum until you reach singularity.
06:50 You would have no chance of moving in the opposite direction.
06:54 There, space and time exchange their roles.
06:57 Time is constantly pulling forward on Earth,
07:00 but in the figurative sense, while it would do so physically inside the hole.
07:05 In a smaller hole, the force of gravity would be stronger at your feet than at your head.
07:10 This is why you would experience a phenomenon of spaghettification.
07:13 This is how scientists call the process where you compress yourself horizontally and stretch out vertically,
07:19 a bit like spaghetti, because of the enormous gravity of the black hole.
07:23 In the meantime, if you had a travel companion in space,
07:26 who, for some reason, would not have ended up in the black hole,
07:29 everything would be different for him.
07:31 He would see you stretch and grow like a huge magnifying glass.
07:35 The closer you would get to the edge of the hole, the more you would feel like you were moving slowly.
07:40 Then you would freeze and the flames would surround you.
07:44 You would be in two places at the same time, living two different fates,
07:48 but there would always be only one copy of you.
07:51 This is how the black holes teach us that nothing is real.
07:55 Reality can be different for different people.
07:58 Some scientists think that we all live inside a huge black hole.
08:03 Everything in the universe began with the Big Bang,
08:06 but according to a theory, there was also something before that.
08:10 It was a super dense grain that concentrated all the mass and energy of the universe,
08:15 about as heavy as a billion suns.
08:18 It was a billion times smaller than any particle observed by humans.
08:23 This grain could be born inside a black hole.
08:26 If we assume that there is more than one universe,
08:29 black holes could also serve as portals between these universes.
08:33 It could be like a root that two trees share.
08:37 You can't see a black hole directly because it emits no light.
08:41 Before, scientists could only spot them by the effect they produced on their environment.
08:46 But when more than 200 scientists from all over the world worked together,
08:50 they managed to take the first pictures of this space oddity.
08:54 The equipment they used, if they were put together,
08:58 would have the power of a telescope the size of Earth.
09:01 Imagine a place where a single day lasts longer than a whole year.
09:06 On Venus, a day, that is to say a complete rotation on its axis,
09:10 is as long as 243 days on Earth.
09:13 And what is even stranger, despite the fact that Venus knows one day without end,
09:18 is that its year is shorter than that of Earth.
09:21 While Earth takes about 365 days to make a complete orbit around the Sun,
09:27 Venus does it in only 225 days.
09:30 So, in a way, for Venus, a day is longer than a whole year.
09:35 Venus is a strange planet in general.
09:38 It is nicknamed the "Earth's twin" because of our similarities.
09:42 Although it is a little smaller than our planet,
09:45 there are also drastic differences.
09:48 For example, it rotates in the opposite direction,
09:51 which means that the Sun rises to the west and sets to the east.
09:55 And Venus is not the only one to dance to its own rhythm.
09:59 Uranus does the same.
10:01 And finally, it's a bit of madness on Venus in terms of atmosphere.
10:04 When you are standing on Earth, you don't really feel the weight of the air around you.
10:09 Well, on Venus, this feeling would be comparable to an elephant sitting on your shoulders.
10:14 Venus has an atmospheric pressure 90 times higher than that of Earth.
10:19 The atmosphere consists of a thick layer of toxic gases.
10:22 For example, the carbon dioxide released by all volcanoes.
10:26 It applies an incredible pressure.
10:28 This is translated by incredibly high temperatures.
10:31 It is therefore surprising that we still have to wait
10:34 before we can set foot on this planet one day.
10:37 Meanwhile, Mercury, the planet closest to the Sun,
10:41 has an orbit even shorter than that of Venus.
10:43 It makes a full journey around the Sun in only about 88 Earth days.
10:48 However, it has a slow rotation on its axis,
10:51 which means that one day on Mercury lasts about 176 Earth days.
10:56 Basically, half a year for us.
10:58 Just like with Venus, a day lasts much longer than a year.
11:01 As it is the planet closest to the Sun,
11:04 it is not surprising that Mercury knows extremely high temperature variations.
11:08 During the day, they can exceed 420 ° C, enough to melt lead.
11:14 But wait for sunset.
11:16 At night, it goes down to a glacial -180 ° C.
11:19 It is because Mercury does not have a thick atmosphere like ours,
11:23 so the heat does not spread evenly across the planet.
11:26 If one side is plunged into darkness, it will be extremely cold,
11:30 and the other side will be burning.
11:32 Just like if you left an ordinary big rock under the sun for a moment.
11:37 In fact, it is so cold that there could even be ice on it.
11:41 Look at the region of the northern pole of the planet.
11:44 Especially its yellow spots, lit by the sun inside the craters.
11:48 They indicate the presence of water ice.
11:50 And it turns out that water is much more common in space than we thought.
11:54 Mars is often nicknamed "the red planet".
11:57 It owes its nickname to the abundance of iron oxide, or rust, covering its surface.
12:02 The rich iron minerals create this reddish hue that colors the Martian landscape.
12:07 But it turns out that Mars is not just red.
12:09 If you stand on Mars, you will see a terrain similar to a desert of caramel colors,
12:14 bathing in a golden glow.
12:16 A little brown here and there, and even slight greenish reflections.
12:20 Mars also has the largest mountain in the entire solar system, Olympus, Mons.
12:25 At a dizzying height of about 22 km above sea level, it is much higher than Mount Everest.
12:31 It was formed by the eruption of a lava with low viscosity,
12:35 creating a structure similar to a shield.
12:38 Since Mars is covered with sand, it is also famous for its fantastic dust storms.
12:43 But it turns out that they are even more insane than we thought.
12:47 These storms can last months.
12:50 Although they may present challenges for future human missions,
12:54 they also contribute to the unreal aspect of the planet when it is observed from afar.
12:59 It is not only the storms to take into account, but also the earthquakes of Mars.
13:04 Also known as seismic tremors, they were detected for the first time by NASA in 2019.
13:11 Unlike earthquakes, which are often triggered by tectonic plate movements,
13:16 we think that the tremors of Mars result from the cooling and contraction of the interior of the planet.
13:22 It is interesting to see how similar and yet so different the two planets are.
13:28 The emblematic rings of Saturn could hold a secret linked to the ancient past of the Earth.
13:33 These rings are mainly composed of ice particles and debris,
13:37 and are estimated to be relatively young on a cosmic scale, only a few hundred million years old.
13:43 Now, some theories claim that they were born after a large-scale disaster.
13:48 The collision of two large moons, or the disintegration of a comet for example.
13:53 What is interesting is that this chronology coincides with the age of the extinction of dinosaurs on Earth.
13:58 Would there be a link? Who knows?
14:00 In fact, although Saturn wins the big prize for its rings, it is not the only planet in our solar system to have it.
14:07 Jupiter, Uranus and Neptune also have their own sets of rings,
14:12 although they may not be as visible and impressive as those of Saturn.
14:16 However, there is something by which Saturn really stands out.
14:21 The magnificent hexagon of its north pole.
14:24 It is a colossal figure with six sides, and each side of this incredible structure measures about 14,500 km long,
14:32 or 1,900 km more than the diameter of the Earth.
14:36 The Sun is a medium-sized star, and yet it could contain 1,300,000 Earths.
14:44 The star is also 333,000 times heavier than our planet.
14:49 NASA has translated radio waves created by the atmosphere of the planets into audible sounds.
14:54 This is how astronomers have discovered that the sound produced by Neptune resembles the waves of the ocean,
15:00 that Jupiter seems to be underwater,
15:03 and that Saturn's voice sounds like the music of horror movies.
15:06 The Earth, it sounds a bit like bebop jazz.
15:09 Okay, I made that up.
15:12 The surface of the Sun is burning, but a lightning bolt is five times hotter.
15:18 The Earth is struck by 100 lightning bolts every second,
15:22 which represents 8 million lightning bolts per day and about 3 billion per year.
15:28 Incredible!
15:30 If you ever manage to go to the Moon and see traces of recent footsteps,
15:34 that doesn't mean there's someone else with you.
15:37 Footprints or other marks of the same type can last a million years there,
15:42 because the Moon has no atmosphere.
15:45 There's no wind, not even a small breeze that could slowly erase these footprints.
15:50 Astronomers have found the biggest hole we've ever seen in the universe.
15:55 It's called the Giant's Void, and it extends over a surface of a billion light years.
16:00 It was accidentally discovered.
16:02 One of the research team members was a little bored
16:05 and wanted to see how things were going in the direction of the cold point.
16:09 It's an anomaly in the cosmological diffuse background map, or FDC in abbreviated.
16:14 It's a faint glow that reaches our planet from different directions and fills the universe.
16:20 It's been going through space for nearly 14 billion years
16:23 and is what's left of the light production that followed the Big Bang.
16:28 So, you fall right in the middle of a black hole, and you're getting ready for a sad end.
16:33 Don't panic.
16:35 Falling into a black hole won't necessarily destroy you, or your spaceship.
16:39 You'd have to choose a large black hole to survive.
16:42 If you fall into a small black hole, what's called the Event Horizon is very narrow.
16:47 Gravity, on the other hand, increases a little more every centimeter.
16:51 So, if you extend your arm forward, there will be a big difference in gravity
16:55 that applies between your fingers and your elbow.
16:57 This will have the effect of stretching your hand, causing a rather unpleasant sensation.
17:02 Very unpleasant, to be honest.
17:03 Things wouldn't be quite the same if you fell into a supermassive black hole
17:07 like the ones in the center of galaxies.
17:10 These objects can be millions of times heavier than the sun.
17:13 Their Event Horizon is vast, and gravity doesn't change that quickly.
17:17 So, the force you'd feel on your heels and at the top of your head would be about the same,
17:22 and you could go all the way to the heart of the black hole.
17:25 Well, that's still to be proven.
17:28 If you watch a very touching movie in space and start crying,
17:32 your tears won't flow.
17:34 They'll accumulate around the ocular globes.
17:37 Your eyes will become too dry, and you'll feel like they're burning.
17:41 All the liquid on your body will evaporate, including the surface of your tongue.
17:46 Speaking of burning, it's something that fire can't do in space.
17:50 Indeed, fire can spread when there's a flow of oxygen.
17:54 And since there isn't any in space...
17:57 Once they've exploded, the stars aren't supposed to come back to life.
18:01 But some stars have somehow survived a big supernova explosion.
18:06 These zombie stars are quite rare.
18:09 Scientists have found a very big one called LP40365.
18:14 It's a partially burned white dwarf.
18:17 A white dwarf is a star that has burned all its hydrogen,
18:20 and this hydrogen was previously its nuclear fuel.
18:24 In this case, the final explosion was perhaps weaker than it usually is,
18:29 not powerful enough to destroy the star as a whole.
18:33 It's as if a star wanted to explode but didn't make it,
18:36 which explains why some of the matter survived.
18:40 If you ever go into space, don't take off your suit,
18:43 except if you're in a spaceship.
18:45 In space, the air in your lungs will spread,
18:47 as will the oxygen in the rest of your body.
18:50 You'll be like a balloon, twice as big as your normal size.
18:54 Good news, the skin is elastic enough to contain you,
18:57 which means you won't explode.
18:59 A little comfort.
19:01 When an object enters a black hole,
19:04 it changes shape and stretches like spaghetti.
19:07 This happens because gravitational force attracts an object in one direction,
19:12 while compressing it in another.
19:15 A kind of pasta paradox.
19:18 In addition, a black hole as big as an atom has the mass of a very large mountain.
19:24 There are some in the centre of the Milky Way, called Sagittarius A.
19:29 It has a mass equivalent to one billion suns,
19:32 but fortunately, it's very far from us.
19:36 If you made a big boom on an asteroid,
19:39 you wouldn't be able to hear its noise.
19:42 Yes, we often hear the sound of spaceships and space battles in movies,
19:46 but it's just a myth.
19:48 Sound is a wave that propagates due to the vibrations of molecules.
19:52 A person taps on a few metres of a roof.
19:55 The sound wave pushes the first air molecule next to the explosion,
19:59 then the second, the third, and so on, until the wave reaches your ear.
20:04 To diffuse sound, we need molecules like air or water.
20:08 In the atmosphere, sound waves propagate very well, but space is empty.
20:13 So there's nothing to hear.
20:15 You can tap loudly in your hands,
20:17 but there won't be any molecule able to vibrate and transport this sound.
20:21 So, to have a conversation,
20:24 You need a radio or a very good reading of the lips.