Les Scientifiques Ont Trouvé Quelque Chose De Terrifiant Dans l’Océan Atlantique

Sympa

Les scientifiques ont découvert quelque chose de véritablement effrayant caché au fond de l'océan Atlantique, digne d'un film de science-fiction. À des kilomètres sous la surface se trouve un immense « bassin de saumure », également connu sous le nom de « lac toxique ». Ce lac sous-marin est si salé et dense qu'il ne se mélange pas avec l'eau de mer environnante, créant son propre petit monde inquiétant. Ce qui est terrifiant ? Il est mortel pour la plupart de la vie marine — tout poisson ou créature qui y nage n'a aucune chance. Mais, de manière étrange, certains organismes uniques y prospèrent, s'adaptant à des conditions extrêmes qui pourraient nous aider à comprendre la survie sur d'autres planètes. C'est un rappel stupéfiant de combien de notre planète est encore inexplorée et pleine de surprises !  Animation créée par Sympa. ---------------------------------------------------------------------------------------- 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 ----------------------------------------------------------------------------------------  Si tu en veux encore plus, fais un tour ici:  http://sympa-sympa.com

Transcript

00:0066 million years ago, maybe in the month of September, a huge asteroid hit the Earth,

00:07sowing chaos and devastation.

00:10The tragic consequences of this terrifying collision have led to the extinction of dinosaurs.

00:15Yes, I want to talk about the asteroid of Chicxulub which left a huge crater in Mexico

00:20and changed life on Earth forever.

00:23Today, it turns out that this is not the only cosmic rock to have hit our planet at that time.

00:28Scientists have just confirmed the existence of another asteroid.

00:32This second asteroid was not as big as Chicxulub, but it still had a hell of an impact.

00:38It crashed off the coast of West Africa, sinking into the ocean and leaving behind a crater, the Nadir crater.

00:46And believe me, its effects are far from insignificant.

00:50The impact was so powerful that it triggered a real tsunami.

00:54These waves rose to more than 790 meters in height,

00:59almost the size of Burj Khalifa, the highest structure ever built by man.

01:04But how did we come to the conclusion that there had been a second impact?

01:09Wisden Nicholson, from the Eriot-Watt University, spotted the Nadir crater in 2022.

01:15Dr. Nicholson examined high-resolution images of the ocean floor

01:19when he noticed a huge depression 9 km wide under nearly 305 meters of water.

01:25He thought it could be an asteroid impact crater,

01:29but at the time, the evidence he had was not solid enough.

01:34Today, scientists have confirmed that it was indeed a crater.

01:38A second asteroid did indeed hit Earth at the time of the extinction of dinosaurs.

01:43Let's see now how they understood that.

01:46First of all, there were these 3D seismic images of very high resolution.

01:51They allowed researchers to separate the layers of the ocean floor

01:55and get a perfectly clear view of the crater.

01:58It's a bit like when you go from a blurry echography to 3D scans where all the details are visible.

02:03Their conclusions confirmed that the crater had been created by an asteroid

02:07with a width of between 457 and 5 cm.

02:10The impact was so intense that it produced a central peak,

02:14created ridges around the crater and even damaged a peripheral area of several thousand kilometers.

02:19With the help of these very detailed images,

02:22scientists have managed to reconstruct what happened

02:25just after the asteroid hit the surface of our planet.

02:28It first hit the ocean, creating a first crater in the shape of a tank.

02:33As the shock wave spread,

02:35the seabed was so violently shaken that there were several landslides.

02:40The furniture sediments surrounding the crater collapsed inwards,

02:44creating a well-visible edge.

02:47As you already know, the impact also triggered a tsunami

02:51whose power was such that the waves did not just spread outwards,

02:56but turned towards the crater,

02:58leaving huge scars on the ocean floor.

03:02And it wasn't just one big wave.

03:04No, there were a whole series.

03:07A succession of tsunamis destroying everything in their path.

03:11This second asteroid impact is a major event for scientists.

03:15It is a rare opportunity for them to study a marine impact crater in such detail.

03:21There are only about twenty confirmed marine craters in the world,

03:25and none of them have been observed with such precision.

03:28In addition, these data allow scientists to test new ideas

03:32on the formation of craters in aquatic environments.

03:35Unlike terrestrial craters,

03:37marine craters are hidden under layers of sediment,

03:41which makes them difficult to study.

03:43But thanks to this new 3D imaging,

03:46we can observe the crater on all its layers.

03:49It's like cutting a cake to see what it's made of.

03:53Dr. Nicholson and his team now dream of drilling into the crater

03:58to collect samples in the depths of the ocean floor.

04:03This would allow them to measure the shock pressure during the impact

04:06and understand what happened in the minutes,

04:09hours and days that followed the collision.

04:12Of course, the Chicxulub asteroid remains the star of the extinction of dinosaurs.

04:17This space traveler was gigantic.

04:20It measured between 10 and 14 km wide.

04:23It hit the Earth at a devastating angle,

04:26projecting rocks and gases vaporized in the atmosphere.

04:30It caused a winter of impact that lasted 15 years,

04:33because all these elements blocked the sun and plunged the Earth into darkness.

04:38The most intriguing thing is that some experts think that the asteroid Nadir

04:42could actually be a fragment of Chicxulub

04:45that would have detached before it hit the Earth.

04:49It's just a theory.

04:51But if it's true, it could mean that our planet

04:54was the victim of a double impact from space.

04:57Let's go back in time.

04:59Until 1908 and in Siberia.

05:01Look around you.

05:03You see nothing but trees and rivers.

05:06And suddenly, a huge object, 45 to 90 meters in diameter,

05:10crosses the Earth's atmosphere.

05:12Is it a comet? An asteroid?

05:15Scientists are not sure.

05:17What they are sure of is that this intruder exploded in the sky of Tunguska,

05:22causing one of the most powerful explosions in history.

05:26It completely razed the forest upside down,

05:29knocking down 80 million trees on a surface of about 2,150 square kilometers.

05:35It's a surface higher than that of cities like Los Angeles or New York.

05:40The trees were literally flattened,

05:43and their trunks stripped of their branches.

05:45Around the epicenter, it formed a strange radial pattern.

05:49And if this explosion had occurred above a city,

05:52all buildings would have been destroyed and countless lives would have been lost.

05:56Fortunately, this disaster occurred in a very remote region of Siberia,

06:01but the most frightening.

06:03When the scientists finally arrived in the region years later,

06:07they found no impact crater.

06:09So it is not surprising that the mystery remains intact.

06:13The most logical explanation is that when the object exploded in the sky,

06:17probably at a distance of 5 to 10 kilometers above the Earth,

06:21it disintegrated before touching the ground,

06:23which did not prevent the explosion from razing an entire forest.

06:27In 2013, another event blew up these products,

06:31this time above a much more populated area.

06:34The city of Chelyabinsk.

06:36It was on an ordinary morning in February that an asteroid of about 18 meters in diameter

06:41entered the Earth's atmosphere, illuminating the sky.

06:44It was moving at a speed of nearly 70,000 kilometers per hour.

06:49It exploded in mid-flight, about 29 kilometers above the city.

06:54The spectacle was terrifying,

06:56but fortunately the asteroid disintegrated high enough in the atmosphere

07:00and did not touch the ground.

07:02If it had, the city would have had very big problems.

07:05Indeed, even if there was no direct impact,

07:08the explosion still created a shock wave that crossed the atmosphere

07:12and hit the ground with enough force to break all the windows.

07:16The explosion damaged about 7,200 buildings,

07:19but luckily there were no direct victims.

07:22There is no doubt that this explosion was a real warning signal.

07:26It was not a distant cosmic event like the Tunguska.

07:30This asteroid exploded above a modern and populated area,

07:34and the damage is very real.

07:36The good news?

07:37Scientists are getting better and better at locating these objects

07:40before they get too close.

07:43Space agencies around the world, like NASA,

07:46track geocruisers to determine what could pose a risk.

07:52But as these two events show,

07:54it happens that space rocks surprise us.

07:58And if the chances of a major impact are low,

08:01the stakes remain very high.

08:03At present, NASA is monitoring an asteroid.

08:06This is Bennu, which is about the same size as the impactor Nadir.

08:10Bennu is considered one of the most dangerous objects in orbit near Earth.

08:14According to NASA,

08:15there is a low risk that it will hit Earth between 2178 and 2290,

08:22with a maximum danger on September 24, 2082.

08:27But don't panic right now.

08:29The probability of an impact is only 1 in 2700.

08:33This reminds us that the Earth is not safe from a cosmic disaster.

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