Pratique du Shadowing: Why Humanity Will Never Leave The Solar System - Apprendre l'anglais à l'oral avec la vidéo
Création de la leçon...
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The latest limited edition pin is here, now available on the Kurzgesag shop.
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You will never leave the solar system.
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Nobody alive today will.
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And maybe no human ever.
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Locked in by an invisible barrier, impossible to overcome for carbon-based animals like us.
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And not just us, there may be millions of alien civilizations in the universe, none of them ever able to venture into deep space in a meaningful way.
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Okay, but how can this be?
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We've made countless videos imagining how the exploration of the galaxy and beyond should just be a question of time,
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sort of mandatory for civilizations at a certain point.
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But there's a catch.
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We're pushing up against fundamental physics.
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What is this barrier made of dust and nothingness?
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And why is it so hard to overcome?
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You don't understand how large space is.
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We don't either.
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Conceptualizing the size of space is impossible for our ape brains
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that evolved to understand distances like right here and over the next hill.
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Space is so absurdly huge that we just check out and just hear very far.
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Very far and a million times very far feels the same.
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But it's not.
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To help our brains, let's start with what makes us cross distances.
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Speed.
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The fastest a human ever traveled in space were astronauts at 40,000 km an hour, returning from the Moon in 1969.
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Not bad, but way too slow.
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The fastest thing humans have ever built by far is the Parker Solar Probe, which at this moment uses a physics cheat code hurling around the gravity well of Venus,
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accelerating to get closer to the Sun.
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After seven years of doing this, the probe is shooting through space at a breathtaking 635,000 kilometers an hour.
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Fast enough to go around the world in four minutes or to cover the distance from Earth to the moon in 36.
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So let's pretend we had a spaceship that fast with a human crew ready to explore the universe.
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Current rockets would need seven to ten months to reach Mars, but our new spaceship covers the distance in just two weeks.
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Pretty good.
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The next stop is Pluto, which will reach after about a year.
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Okay, much longer, but still okay.
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It only takes two more years to pass the heliopause and one more to pass Voyager 2, which traveled over 50 years to get this far.
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Great!
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The next stop is the end of the Oort cloud, the true edge of the solar system where open space begins.
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We reach it in...
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2,500 years!
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Oh.
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Oh no.
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Not only did we travel for the amount of time it
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took to get from the founding of the Roman Republic to the present day, there's nothing out here.
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This is the invisible barrier, the barrier of nothingness that might trap us in the solar system forever.
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Space tends to be like that.
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There is a place that's very far away, but with human ingenuity and billions of dollars, we can get there.
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Then you zoom out one more time and all hope leaves your body.
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And the problem is that we've barely started zooming out.
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Why don't we just go faster?
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Well, we don't know of a non-magic way to travel faster than light, teleport or freeze people.
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So, no warp drive for now.
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But things like a propulsion system that uses nuclear fusion or antimatter, powerful enough to reach a substantial fraction of the speed of light, are in the realm of the physically possible.
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Ignoring the technical details and various problems that these energy sources have, we'll be very optimistic and make the reasonable assumption
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that we can get a spaceship to fly at around 20% the speed of light, which is extremely fast — 60,000 km per second,
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216 million km per hour.
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enough to reach the edge of the solar system in just 3.5 days
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and the outer edge of the Ork cloud in 8 years.
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Alpha Centauri, the closest star system to our own, in 20 years.
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We can work with that.
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There's only one small problem.
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We don't have internet!
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Wait, what?
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Just kidding.
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But our sponsor Saily can help you with that problem while traveling.
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Saily is the eSIM service app from the creators of NordVPN.
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You can choose from a wide range of affordable eSIM plans for over 200 destinations, so you'll never be without an internet connection while traveling.
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Just download the app, pick a data plan, use the code Kurzgesagt for a 15% discount on your first data package and install the eSIM in advance.
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It'll activate automatically when you arrive and you can start browsing right away.
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It now comes with an app-based phone number for voice calls and SMS that stays the same everywhere.
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Perfect for local apps, shops and travel companions.
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All you have to do is pick your next destination.
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We'll go back to solving our trickier travel problems.
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Everything should be sorted out now, right?
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Well, there's only one small issue.
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Space hates you.
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The barrier of dust.
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Unfortunately we'll run into a few obstacles on the way.
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Literally.
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Because while space is very empty, it's not actually empty.
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There are energetic particles, gas, dust and things bigger than dust.
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As a lot of unhappy people experience every day, if you're going really fast and smash into something, you have a huge problem.
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And, at 20% the speed of light, this is true even if the thing you're smashing into is just an atom.
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An individual iron atom
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that hits your spaceship at this speed has enough energy to carve a damage track tenths of a millimetre deep.
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Over time, its hull will be riddled with microscopic bullet holes, which is not great.
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Of course, our engineers knew this and created a shield for our ship, a sort of protective sail that absorbs or at least slows down most molecules we smash into.
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And while this makes the journey much safer, there are things floating around in space that are larger than atoms.
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Running into a single grain of dust at 20% the speed of light is like running into a grenade, causing a tiny detonation as the dust explosively evaporates,
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grinding away our protective shield.
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But you can also hit something bigger than a grain of dust, like a small rock the size of a golf ball.
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Hitting that at 20% the speed of light
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releases more than double the energy of the nuclear bomb that was dropped over Hiroshima.
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We'll not even talk about anything larger.
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Atoms, dust, and pebbles are dangerous enough.
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We might have reached our natural speed limit here.
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Beside the fact that we don't have a good idea how we could possibly fly any faster, all of the damaging effects of hitting stuff floating around in the void get much worse fast.
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Having said all that, it's probably fair to assume that with enough shielding, our spaceship should be able to survive traveling through space at
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roughly 20% the speed of light long enough to get to at least nearby stars in a reasonable amount of time.
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Only one more issue to overcome.
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Almost everything in space that's close is super lame.
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The first proper target outside the solar system is the Alpha Centauri system, which is roughly 10,000 years with our original slow,
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more realistic ship, but only 20 years with our super-fast fictional ship.
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So, let's cram a few unlucky humans into a tiny box for 20 years, and send them on their way, and assume they somehow make it without murdering each other.
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Four years after their arrival, their message reaches Earth.
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Earth.
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People around the globe gather together and hold their breath, eager to listen to it.
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We arrived.
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Alpha Centauri and its planets are very pretty up close.
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Unfortunately, they're all super deadly and uninhabitable.
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But we're doing extremely cool astrophysics and are learning a lot, which is pretty exciting.
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We're getting kind of tired of freeze-dried food and desperately need new shows to watch though.
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Not sure what we were thinking coming here.
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The thing about space is that almost all close destinations, if close means something different from what it usually means, are pretty lame.
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Not from a scientific perspective, of course.
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It would be an absolute dream to have the privilege to set foot on foreign planets
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and marvel at the wonders of our universe.
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But if 20% of the speed of light might be our speed limit, and we give humans a realistic travel time of say 40 years, we could reach things that are up to 8 light years away.
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None of the targets remotely within this range within a human
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lifetime may be worth traveling dozens of years in a tiny box through one of the deadliest environments imaginable.
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Our solar system is a bit unlucky in that regard.
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We're in a relatively empty pocket of the galaxy.
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This might change in a few million years as we move through the galaxy and there might be small, localized star-spanning civilizations.
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We discuss this in another video.
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Let's say that we could go much further, to any of the stars within our stellar neighborhood, a sphere about 25 light years in diameter.
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0.02% of the Milky Way, by the way.
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This tiny bubble is currently inhabited by 34 stars and 6 brown dwarfs.
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Only 3 stars in our neighborhood are similar to the Sun.
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But one of them is actually the Sun, and another one is Alpha Centauri A.
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The other stars close to us are mostly red dwarfs, with planets that vary from deadly to super deadly.
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There are a few planets in the habitable zones of their stars, where water can be liquid.
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But Mars is also in the habitable zone of the Sun, and it's really bad.
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Even the planets that we think look most like Earth, like GJ1061D, come with no guarantees.
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Imagine traveling your entire life, and then arriving at a Mars.
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What a brutal letdown that would be!
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There are a few stars that would be interesting targets, and may have actual habitable planets.
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Planets with oceans and atmospheres that are breathable, which probably would mean that they have some form of microbial life, if not more.
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It would be extremely interesting and definitely worth it to check them out.
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But they could be dozens if not thousands of light years away, which means journeys of hundreds or thousands of years, even at a large fraction of the speed of light.
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Of course, it is maybe feasible that a future humanity
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that is technologically way more advanced than us and very motivated could find solutions.
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Maybe they've solved biological aging and a travel time of a few hundred years doesn't seem that bad to them.
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Maybe they could send AI spaceships with embryos or some version of that into space.
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They probably have way more advanced telescopes to make sure they don't choose star systems that are deadly and empty.
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But it's still hard to imagine without real science fiction technology how they could build and sustain a connected civilization.
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Conclusion The longer you think about deep space the less it makes sense.
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The distances are too vast.
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There's a deadly speed limit and even
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if we could solve these issues almost all destinations even remotely reachable may not be worth the trip.
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Space is the greatest challenge humanity will ever face.
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Right now, we're just not equipped or able to solve it.
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Rockets, computers and even nuclear fusion reactors are hopelessly underpowered.
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We need technology that's overwhelmingly transformative.
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Something as wild to us as flying to the moon would have been to a hunter-gatherer.
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Will we ever get there?
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We genuinely don't know.
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But it is good to remind yourself of something.
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There are few things that make you look dumber than predicting the future of technology.
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In 1903, the New York Times published an editorial, Flying Machines Which Do Not Fly,
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that confidently predicted it would take humans 1 to 10 million years to achieve powered flight.
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69 days later, the first successful flight happened.
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66 years later, humans landed on the moon.
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So, we really hope this video will seem as dumb as this article in 100 years.
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And there's another option entirely, maybe our thinking about all of this is just completely wrong.
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Maybe the future is not out there, but deep down.
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But we'll explore that in another video.
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The latest limited edition pin is here, continuing the cosmic time collection.
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Predicting the future is really hard, but this device offers you a rare glimpse into the end of the universe.
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one by one, all the stars will die until everything is swallowed by darkness.
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Wear this animated lenticular pin as a reminder that you exist right now, in a brief and extraordinary moment in time
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when the universe is still filled with stars and light and there's so much left to discover.
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You're exactly where you belong in cosmic time and the universe.
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Only 10,000 Vanishing Stars pins exist and each one is individually numbered.
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Add it to your collection or start a new one while supplies last.
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And while humanity may still be confined to a tiny corner of the cosmos, we've already achieved some remarkable things.
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To celebrate these milestones, we created our Cosmic Milestones poster collection, featuring the first moon landing, the Mars rover Curiosity, and the Wilson Observatory,
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all enhanced with shimmering foil details.
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Get your favorite, or better, all of them, and create a gallery wall
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that will inspire you every day and remind you of what humanity is capable of.
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Head over to our shop, we've put together a few deals for you.
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Vocabulaire et conseils d’expression pour cette leçon
Cette leçon d’expression orale de niveau C1 s’appuie sur la vidéo « Why Humanity Will Never Leave The Solar System ». Les mots qui reviennent le plus souvent : space, speed, star. Cette vidéo contient 183 phrases et 2329 mots à répéter en shadowing. La partie parlée dure 13:51. Le locuteur parle à un rythme naturel d’environ 168 mots par minute, proche d’une conversation courante. Seuls 81 % des mots font partie des 3 000 mots les plus courants en anglais, le vocabulaire est donc exigeant.
Vocabulaire clé de cette vidéo
Les 15 mots les plus avancés de la vidéo, avec leur prononciation et leur sens :
| Mot | Prononciation | Sens |
|---|---|---|
| spaceship nom | vaisseau spatial, astronef | |
| atom nom | /ˈætəm/ | atome |
| civilization nom | /ˌsɪv.ɪ.laɪˈzeɪ.ʃən/ | civilisation |
| cosmic adjectif | /ˈkɑz.mɪk/ | cosmique |
| predict verbe | /pɹɪˈdɪkt/ | prédire |
| smash verbe | /smæʃ/ | fracasser |
| nothingness nom | néant | |
| cosmos nom | /ˈkɑzməs/ | cosmos |
| unlucky adjectif | /ʌnˈlʌki/ | malchanceux, poissard |
| milestone nom | /ˈmaɪlˌstoʊn/ | borne, borne kilométrique |
| remotely adverbe | /ɹɪˈmoʊtli/ | à distance |
| float verbe | /fləʊt/ | flotter |
| fraction nom | /ˈfɹæk.ʃən/ | fraction |
| probe nom | /pɹoʊb/ | sonde, explorateur |
| fusion nom | /ˈfjuː.ʒən/ | fusion |
Les verbes à particule que vous entendrez
| Mot | Prononciation | Sens |
|---|---|---|
| zoom out verbe | /ˌzuːm ˈaʊt/ | dézoomer |
| check out verbe | mater, regarder | |
| put together verbe | assembler | |
| slow down verbe | ralentir, décélérer | |
| sort out verbe | résoudre |
Des phrases à répéter
Des phrases courtes et complètes de la vidéo, à réutiliser dans la conversation de tous les jours :
- We're pushing up against fundamental physics.
- You don't understand how large space is.
- Why don't we just go faster?
- We'll go back to solving our trickier travel problems.
- Will we ever get there?
La grammaire de cette vidéo
Les structures que le locuteur utilise le plus, avec les mots exacts de la vidéo :
| Structure | Dans la vidéo |
|---|---|
| Present perfect have/has + participe passé — une action passée qui compte encore maintenant | We've made · have ever built · you've solved |
| Voix passive be + participe passé — l’accent est mis sur ce qui arrive, pas sur qui le fait | should be sorted · will be riddled · was dropped |
| Propositions relatives who / which + proposition — une précision sur une personne ou une chose | Pluto, which will · light, which is · holes, which is |
Prononciation à surveiller
Le locuteur utilise 31 contractions et formes réduites, comme don't, we'll, we're. Prononcez-les sous leur forme courte, telles que vous les entendez.
- Les sons « th »: breathable /ˈbɹiːðəbəl/, breathtaking /ˈbɹɛθˌteɪ.kɪŋ/
- Les sons « sh » et « zh »: civilization /ˌsɪv.ɪ.laɪˈzeɪ.ʃən/, smash /smæʃ/, fraction /ˈfɹæk.ʃən/, fusion /ˈfjuː.ʒən/, fictional /ˈfɪkʃənəl/
- Mots longs — placez bien l’accent: civilization /ˌsɪv.ɪ.laɪˈzeɪ.ʃən/, habitable /ˈhæbɪtəbəl/, invisible /ɪnˈvɪzəb(ə)l/, antimatter /ˈæn.tiˌmæt.ɚ/, astrophysics /ˌæs.tɹoʊˈfɪz.ɪks/
Les sons difficiles pour les francophones :
- /h/ — il se souffle, il n’est pas muet: habitable /ˈhæbɪtəbəl/, inhabited /ɪnˈhæbɪtɪd/, enhance /ɪnˈhæns/, unhappy /ʌnˈhæpi/, hull /hʌl/
- /tʃ/ et /dʒ/ — à ne pas adoucir en « ch » et « j »: checkout /ˈt͡ʃɛkˌaʊt/, energetic /ˌɛn.əɹˈdʒɛt.ɪk/, individually /ˌɪndɪˈvɪd͡ʒ(u)əli/, cheat /ˈt͡ʃiːt/
- /r/ anglais — langue recourbée, sans frotter la gorge: predict /pɹɪˈdɪkt/, remotely /ɹɪˈmoʊtli/, fraction /ˈfɹæk.ʃən/, probe /pɹoʊb/, astrophysics /ˌæs.tɹoʊˈfɪz.ɪks/
Comment s’entraîner avec cette vidéo
- Écoutez la vidéo en entier une fois sans parler et notez les mots que vous ne connaissez pas.
- Commencez à la vitesse 0,75×, répétez phrase par phrase, puis revenez à la vitesse normale quand cela devient facile.
- Enregistrez-vous et comparez avec l’original, en faisant attention à des mots comme spaceship, atom, civilization.
Qu'est-ce que la technique du Shadowing ?
Le Shadowing est une technique d'apprentissage des langues fondée sur la science, développée à l'origine pour la formation des interprètes professionnels. Le principe est simple mais puissant : vous écoutez de l'anglais natif et le répétez immédiatement à voix haute — comme une ombre suivant le locuteur avec un décalage de 1 à 2 secondes. Les recherches montrent une amélioration significative de la précision de la prononciation, de l'intonation, du rythme, des liaisons, de la compréhension orale et de la fluidité.