En 20 minutes, nous allons nous plonger dans des scénarios très fous ! Imaginez : déverser toutes les gouttes d'eau dont nous disposons directement sur le soleil brûlant - vous parlez d'une chute aux proportions épiques ! Et ce n'est qu'un début : et si nous construisions un pont entre la Terre et Mars, ou si nous transformions la Lune en une boule disco géante ? C'est comme un brainstorming sous stéroïdes, avec des idées plus folles qu'un tour de montagnes russes. Alors, préparez votre casse-croûte et laissez libre cours à votre imagination. Vous allez découvrir les idées les plus farfelues que vous ayez jamais entendues ! Animation créée par Sympa.
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Si tu en veux encore plus, fais un tour ici:
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Musique par Epidemic Sound https://www.epidemicsound.com
Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna
----------------------------------------------------------------------------------------
Nos réseaux sociaux :
Facebook: https://www.facebook.com/sympasympacom/
Instagram: https://www.instagram.com/sympa.officiel/
Stock de fichiers (photos, vidéos et autres):
https://www.depositphotos.com
https://www.shutterstock.com
https://www.eastnews.ru
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Si tu en veux encore plus, fais un tour ici:
http://sympa-sympa.com
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FunTranscript
00:00Is it possible to extinguish the Sun?
00:04For example, what would happen if we poured all the oceans of the Earth into it,
00:08or even more water?
00:11Well, let's find out together!
00:13The universe is a place full of mysteries.
00:16Since immemorial times, scientists have wondered about the functioning of space.
00:20But none of us has ever doubted the existence of one thing, the Sun.
00:26Ah, the center of our solar system!
00:29Is it big, bright and ... immortal?
00:32No, not really.
00:34In fact, the Sun is just an ordinary star.
00:37It is composed of 75% hydrogen, a little helium and a pinch of other heavy elements.
00:43Gravity keeps it all together.
00:45But in about 5 billion years, the Sun's life cycle will come to an end.
00:51The hydrogen it contains will run out.
00:53Our star will begin to grow progressively.
00:56And you can't even imagine how big it will become.
01:00And then, it will begin to devour all the nearby planets.
01:04It is at this moment that we will regret being so close to it.
01:07After absorbing us all, the star will remain a red giant for another billion years or so.
01:14And then, sooner or later, it will begin to shrink and extinguish,
01:18turning into a white dwarf.
01:20In the end, all that will remain of it is a bright and colorful nebula.
01:25But don't be afraid.
01:27At the moment, the Sun is in the middle of its life cycle.
01:30It was born about 4.5 billion years ago, and it has about as much time in front of it.
01:36Fortunately, we appeared during the most favorable and stable period of this star.
01:41In other words, there is no reason to worry.
01:45But let's try to imagine one.
01:47What if we accelerated the Sun's life cycle by using ...
01:51water.
01:52We will try to gather all the water on Earth and pour it on the Sun.
01:56First of all, we will need a bucket.
01:59No, not this one.
02:00We will need a very, very big bucket.
02:03One that can contain about 1,360,000,000 cubic kilometers of water.
02:08Its size would be equal to the distance between Washington and Chicago.
02:12Or if we can only find ordinary buckets, we would need about 70 trillion of them.
02:18Yes, we are talking about a number of 18 zeros.
02:21Well, imagine that we have obtained such a quantity of buckets by magic.
02:25It is time to extinguish the Sun.
02:27We sprinkle the star with all this water and ...
02:30Nothing? Seriously?
02:32Oh, look at that!
02:33The Sun probably had mercy on us and produced a very small solar eruption.
02:38It turns out that all the water on Earth is actually just a ridiculous droplet for the Sun.
02:44People often underestimate how much the Sun is infinitely larger than our planet.
02:49In fact, it can contain more than 1,300,000,000 Earths.
02:54So, indeed, the Sun will not go out and will not even get colder.
02:59It will not even notice that we have done anything.
03:02But let's not give up.
03:04We really want to extinguish the Sun for one reason or another.
03:08What happens if we just pour enough water on it?
03:12And how much does this enough represent?
03:15Do you remember our trillion buckets?
03:17Well, we actually need about 370 quadrillion of these.
03:22This number is 27 zeros.
03:24It's hard to imagine, so let's just say it's a lot of water.
03:29Now, let's pour all this on the Sun again.
03:32Wow! Look at this steam!
03:35But the Sun has not yet gone out.
03:38On the contrary, it says thank you and suddenly becomes much larger and much brighter.
03:44What's going on?
03:46As you can see, the Sun is not a common campfire.
03:49In campfires and candle flames, there is a chemical combustion.
03:53When we pour water on the fire,
03:55the water absorbs the heat of the flame and cools it
03:58to such an extent that it can no longer maintain the combustion reaction.
04:01It also blocks the access of the fire to oxygen.
04:04Basically, the water interrupts the chemical process.
04:07But the combustion of the Sun is not the same reaction.
04:11Even if we say it burns, it's not quite true.
04:14What's going on over there is what we call nuclear fusion.
04:18It is one of the most powerful and most insensitive reactions in the universe.
04:23There are many layers of hydrogen that sink deeply into the Sun.
04:27If you take four atoms of hydrogen and they fuse,
04:30you end up with an atom of helium.
04:33When we talk about the Sun, the process is a little more complicated.
04:37When the star tries to produce this fusion,
04:40the positive protons repel each other.
04:43So you need a lot of strength and energy to be able to push them together.
04:48Woosh! Your spaceship is almost here.
04:51Thanks to the latest technology, you can now travel to any planet in our solar system
04:56faster than ever.
04:58And we can finally visit other planets in complete safety.
05:01You have registered for a trip into space
05:03and you are now on board a spaceship with your guide,
05:06astronauts and a few other passengers.
05:08First stop, the smallest planet in our solar system, Mercury.
05:12It is only a third of the distance from the Earth to the Sun.
05:15The view will be spectacular.
05:17As soon as your ship lands on the solid surface of this rocky planet,
05:20you see an endless universe.
05:22Stars, comets passing by and ... the Sun.
05:25Three times larger than what we see from Earth.
05:28Without any clouds to hinder the view.
05:30There is no moon. Mercury and Venus do not.
05:33You try to move, but because of your spatial combination and reduced gravity,
05:37you feel like you're on a trampoline in a slow motion movie.
05:41It is not safe to come here during the day.
05:43On Mercury, it lasts almost 59 terrestrial days.
05:46Although your space suit protects you,
05:49temperatures can become quite extreme.
05:51During the day, it goes up to 430 degrees.
05:54There is no atmosphere to keep the heat,
05:56so the temperature during the night can go down to 180 degrees.
06:00This is why Mercury is not the warmest planet,
06:02even if it is the closest to the Sun.
06:04Venus is the second closest,
06:06but it has an atmosphere that retains its heat.
06:08You are safe in your adapted space suit,
06:11but it will still be very difficult to undergo such radical temperature changes,
06:15so you have to hurry.
06:17Mercury has a lower gravity because it weighs less than Earth,
06:20which means that gravity on Mercury pulls less on your body.
06:23If a person weighs 45 kilos on Earth,
06:26she would weigh 17 kilos on Mercury.
06:28And you really feel lighter.
06:30Hurry up, we don't have much time.
06:32You hear the voice of your guide in your space suit.
06:34He is standing next to you and points something with his finger.
06:37Look to your left, that's why we are here.
06:40The Calorie Basin.
06:41Breathtaking.
06:42Mercury's atmosphere is so thin
06:44that nothing protects the planet from asteroids that hit its surface.
06:48It is the one with the most craters in our solar system.
06:51That's why it reminds you of the Moon.
06:53And now you are there, looking at the Calorie Basin,
06:56the largest impact crater in the entire solar system,
07:00formed almost 4 billion years ago
07:02by an object at least 97 kilometers long.
07:05You can see its rocky interior,
07:07filled with deep crevasses and high ridges,
07:09surrounded by the highest mountains that can be found on this planet,
07:13which rise to 3,000 meters above many volcanic chimneys.
07:17They were active in the past.
07:19The other side, which is hidden from the sun,
07:21contains tiny deposits of ice.
07:23It is the only form of water found here,
07:25but you won't have time to see it.
07:28It all started with a minor change on our planet.
07:31First of all, people noticed that the Moon had become brighter
07:35and a little bigger.
07:37But no one paid attention to it.
07:39It affected the tides all over the world,
07:41so that the water submerged the beaches.
07:44But it wasn't a tragedy.
07:46Many fish came closer to the shore.
07:48People started to find giant squid,
07:51cod and other creatures close to the coast,
07:54while they usually lived in the dark depths.
07:57New and stranger things happen every day.
08:00Birds no longer fly south in winter.
08:03They gather in huge swarms,
08:05flying around cities without a precise destination.
08:08The Moon helped them to find their way in nature,
08:10but now they can no longer know in which direction to fly.
08:14From the seas,
08:15the ship's captains notice that the compasses are now unstable.
08:19The arrow points in different directions
08:21since the magnetic poles of the Earth have changed.
08:24People realize that the Moon has started to approach it
08:27for an unknown reason.
08:29The gravity of the Moon affects that of our planet.
08:33This leads to changes in the climate,
08:35in the behavior of all living things,
08:37and in the magnetic field.
08:39Now, it rains in the driest places,
08:42and it's hot in the coldest lands.
08:44This harms the ecosystems of the whole planet.
08:47People who live near forests
08:49often hear wolves howling,
08:51because the Moon makes these animals go crazy.
08:54The Earth's natural satellite
08:56never ceases to grow,
08:57and illuminates the night in a much brighter way.
09:00Nothing irremediable has happened yet.
09:03People still don't panic,
09:05because they don't want to believe that the end is coming.
09:07But one day, the Moon reaches a critical point.
09:11You walk down the street, listening to music,
09:14and at that moment, someone bumps into you.
09:16Well, this guy may be late for work.
09:19You keep walking,
09:21and a girl passes by and hits your shoulder.
09:23Sorry, sorry, she says.
09:25Then she leaves.
09:27You could see fear in her eyes.
09:29You look in front of you,
09:31and see people running in your direction.
09:33You finally take off your headphones,
09:35and you hear screams and sirens.
09:37People leave their cars and run away.
09:39Hundreds of seagulls fly in the sky.
09:42You hear a strange noise among all this noise.
09:45It seems to be...
09:47water!
09:48How is this possible?
09:49You are in the city center,
09:51a few kilometers from the coast.
09:53You don't have time to think.
09:55You notice that a huge wave floods the streets
09:58and heads straight for you.
10:00You run into a building and climb to the 10th floor.
10:03From here, you watch the water submerging the city.
10:07The powerful torrent carries all the cars,
10:09the buildings on one floor,
10:11and the trees on its road.
10:13You notice a shark fin and other fish in the water.
10:17Imagine a planet where every breath
10:19fills your body with energy,
10:21like an espresso.
10:23The sky above you is an intense blue,
10:25while gargantuan trees
10:27spread far into the atmosphere,
10:29their leaves of a sparkling glass
10:31pushing at a stupefying speed.
10:34Your daily jogging becomes an unparalleled pleasure.
10:37Thanks to the abundance of oxygen,
10:39you become a boosted version of yourself.
10:42Running is done effortlessly,
10:44while you rush through the landscape
10:47and lift weights that would normally seem unmovable to you.
10:50It's as if the world itself
10:52was imbued with energy.
10:54Everything goes faster.
10:56The fauna that surrounds you
10:58is also affected by this overload of oxygen.
11:01Animals gallop on land with grace,
11:03their massive bones propelled
11:05by an unparalleled agility.
11:07Imagine yourself in a thrilling chase
11:09with a cheetah doped with oxygen
11:11facing a predator
11:13that could bring misery to a Ferrari.
11:15You may wonder how such a scenario
11:17could be possible.
11:19Let's see.
11:21Oxygen is the powerful fuel
11:23that allows terrestrial life to exist as such.
11:26It constitutes about 21% of the air we breathe
11:30and every breath we take
11:32transmits these small molecules to our cells,
11:35providing them with the energy they need to develop.
11:38Without oxygen, they would be suffocated
11:41and our bodies would collapse.
11:43But that's not all.
11:45Oxygen is a panacea that works for all kinds of living beings.
11:48From tiny bacteria to gigantic elephants.
11:51It is even crucial underwater,
11:53where it enriches the oceans.
11:55Amazing creatures like plankton and algae
11:57produce a lot of oxygen,
11:59thus creating a prosperous underwater world.
12:02But to fully understand the impact
12:04of high oxygen levels on the planet,
12:06get ready for a little time travel.
12:09Recently, scientists made an amazing discovery.
12:12They tested rocks from two different places
12:16and guess what?
12:18These rocks contained tiny gas pockets
12:21which showed how oxygen levels had increased
12:24by nearly a third in a very short time,
12:26like a breath of fresh air on a planetary scale.
12:29The researchers therefore studied these rocks
12:32and discovered that oxygen levels
12:34were much higher at the time.
12:36Imagine luxurious landscapes,
12:38impenetrable forests
12:40and huge swamps that spread at close range.
12:44During the Carboniferous period,
12:46oxygen permeated the atmosphere
12:48with an impressive concentration of 20%,
12:50just like today.
12:52But over the next 50 million years,
12:54its content has gone up to 35%.
12:58Can you imagine what happened?
13:00The increase in oxygen levels
13:02caused an incredible phenomenon.
13:04Huge forests grew all over the Earth,
13:06creating a greenish world that was breathtaking.
13:09Vast swamps spread in low altitude areas,
13:12giving the landscape a surrealistic look.
13:15At the same time,
13:17carbon dioxide levels dropped.
13:19Normally, when things decompose,
13:21microbes release carbon dioxide into the air.
13:24Imagine a wandering planet,
13:26a cosmic vagabond
13:28that no one would want to accompany home.
13:31Basically, a wandering planet
13:33has already been ejected from its own stellar system
13:36and now floats aimlessly in space,
13:38like a lonely cosmic cowboy.
13:40These planets are not purely theoretical.
13:42They exist,
13:44and scientists have even detected them in our galaxy.
13:46In fact, estimates suggest
13:48that there could be many of these cosmonomads
13:50floating around the Milky Way.
13:52And they are not just small rocky universes like Earth.
13:56Some of them are massive gas giants,
13:59several times larger than Jupiter.
14:01These mastodons could potentially have their own moon
14:04and even their own mini-system in orbit around them.
14:08For example,
14:10one of the most famous wandering planets we know
14:12bears a complicated name.
14:14Here, read it yourself.
14:16It is located about 80 light years from Earth,
14:19and was discovered in 2013.
14:22Its mass is estimated to be about 6 times that of Jupiter,
14:26and it would be about 12 million years old.
14:29And yes,
14:31it's not because these cosmic loners don't have stars
14:33that they are mega-cold.
14:35They can still generate heat and light
14:37from their own internal processes.
14:40Some can even have magnetic fields and auroras,
14:43just like Earth.
14:45In other words,
14:46wandering planets could potentially be habitable
14:48if they met the right conditions.
14:50So,
14:51what would life look like on such a planet?
14:54And could we possibly live in such a world?
14:57Well,
14:58existing on a wandering planet
15:00can be a very lonely existence.
15:02There is no sun to lean on,
15:05and no cosmic neighbors to have a barbecue with.
15:08Ouch.
15:09That's why we need to be creative.
15:11Let's start with the most obvious problem.
15:13It will be difficult to do without light and heat.
15:16How can we solve this problem?
15:18Well,
15:19we should probably invest in very sophisticated space heating
15:23and wear space suits,
15:25super warm.
15:26We could also invent a whole new way
15:28to produce electricity
15:30without depending on solar energy.
15:32For example,
15:33why not use geothermal energy?
15:35That's serious.
15:37Each planet has an internal source of heat.
15:40Without it,
15:41they would only be cold rocks
15:43and no life floating in space.
15:45This source of heat could be exploited
15:48and used to power houses, factories,
15:51and spaceships.
15:53It's as if you had a big enough jacuzzi
15:55to power an entire city.
15:57And this city will certainly be located underground,
16:00closest to the source of heat.
16:03As for light,
16:04we would probably need to make ultra-powerful flashlights
16:08or maybe even learn to genetically create
16:11bioluminescent organisms to light our houses.
16:14Imagine space bases
16:16full of mushrooms and fluorescent plants.
16:19Speaking of plants,
16:21the presence of plants would be quite difficult to obtain without stars.
16:25So what would we eat?
16:27Well, we could use the same geothermal sources we talked about
16:31or certain chemical reactions to meet our needs.
16:34And maybe we would develop a taste for food rich in sulfur
16:38or we would start fermenting our own drinks
16:41from boiling volcanic mud.
16:43Yum!
16:44But apart from food,
16:46we have a bigger problem.
16:48Living on a wandering planet would be like cutting your breath,
16:51literally,
16:52because we would have no air.
16:53You see,
16:54all wandering planets do not have a viable and stable atmosphere.
16:57It all depends on their size, their composition and other factors.
17:01But even if our new house had an atmosphere,
17:04it could be incredibly thin and precarious.
17:07We would not have beautiful blue skies
17:09or spectacular sunsets to admire.
17:12Instead,
17:13we would look into the infinite void of space
17:16where the stars would be brighter than ever.
17:19And forget about meteorological phenomena.
17:21Without atmosphere to create them,
17:23we would have no rain, no snow, no storm.
17:26And these are just the smallest of the problems.
17:29The worst is that the planet's temperature would fluctuate enormously,
17:33going from an unbearable heat to an unbearable cold.
17:36It would be like living in an oven
17:38that would be constantly turned on and off.
17:41And finally,
17:42we would be exposed to all kinds of space debris and cosmic radiation.