L'Antarctique a un secret étrange : c'est l'un des meilleurs endroits sur Terre pour trouver des météorites ! Ce continent glacé peut sembler comme un lieu étrange pour cela, mais il y a une raison pour laquelle tant de roches spatiales y sont découvertes. Lorsque des météores atterrissent sur la glace blanche, ils sont beaucoup plus faciles à repérer que dans les zones rocheuses ou boisées. De plus, les calottes glaciaires s'écoulent lentement et poussent les météorites enfouies vers la surface, les rendant encore plus faciles à trouver. Les températures glaciales aident également à préserver ces roches spatiales, les gardant en excellente condition pour que les scientifiques puissent les étudier. Ainsi, malgré les conditions rudes de l'Antarctique, c'est une mine d'or pour les chasseurs de météorites désireux d'en apprendre davantage sur notre système solaire ! 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
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00:00Look at this stone. At first glance, it looks like one of those ordinary pebbles that you can see when you walk on the beach.
00:08It is not particularly colorful, nor particularly heavy, about 2 kg.
00:13But if I told you that this stone was born on Mars, that it traveled to Earth to finally arrive in Antarctica.
00:20Ah, now the story is much more fascinating. So, let's discover all this.
00:26The researcher Roberta Skor, who worked on the project ANSMET, or Antarctic Search for Meteorites, of the Denver Antarctic Program,
00:34found the meteorite in 1984.
00:37If you want to decipher the name of this space traveler, I can help you.
00:41First of all, this is the place where it was found. The hills of Alan in Antarctica, or Alan Hills.
00:48Then, we have the year of its discovery and the number of the sample.
00:52If you tell yourself that our friend Roberta picked up this stone by exclaiming,
00:56Wow, a piece of Mars, you will be disappointed.
00:59At first, it was totally impossible to know where the meteorite came from.
01:03And something was even more disturbing for the researchers.
01:06This stone was very different from other types of meteorites found on our planet.
01:11Okay, but how did they finally discover that it came from Mars?
01:16Thanks to gas traces similar to those that make up the atmosphere of the red planet.
01:21We learned about its composition thanks to the brave Viking Lander,
01:25who carried out the necessary analyses in situ in 1976.
01:30But let's go back to our discovery. It is very special.
01:34And not only because it comes from far away.
01:37Among the few thousand meteorites found on Earth, only about a hundred probably come from Mars.
01:44And even with that, our little one is different from the others, and seems to be part of a separate group.
01:50So let's go back to the past, and retrace the story of this cosmic traveler.
01:55It probably formed about 4 billion years ago on its native red planet.
02:00One day, which was not very different from the others, the life of this peaceful pebble was upset.
02:06A meteor impact catapulted it into space.
02:09And our stone began its journey as a small asteroid.
02:12At the time, it was much larger than at the time of its discovery on Earth.
02:16At one point, it approached the Earth, and it looks like it decided to explore the places.
02:22This is how, 13,000 years ago, ALH ended its space travel by colliding with our planet.
02:29At present, this Martian fragment is the oldest we have ever found.
02:34But at first, it was not very popular.
02:36It was only in 1996 that its notoriety suddenly increased, following a revolutionary discovery.
02:43NASA researchers have indeed wondered.
02:46This fragment is obviously very old.
02:49But could it have recorded traces of life that could have prospered on Mars at the time when ALH was still attached to the red planet?
02:57And guess what?
02:58It was a very good question.
03:00They detected traces of very fine magnetic particles.
03:04Their structure and chemical composition are quite similar to those of the particles found on our planet.
03:10They are called fossil magnetos.
03:12And it is magnetotactic bacteria that produce them.
03:15This could mean that there were, at some point, life forms on Mars.
03:19In April 2020, Japanese space agency scientists made another discovery.
03:25They detected in our meteorite nitrogen containing organic materials of Martian origin.
03:31So who knows what new surprising secrets a more in-depth examination of the meteorite could reveal to us?
03:37For now, all you have to do is go to Antarctica and start digging.
03:42Indeed, it is an ideal place for meteorite hunting.
03:46We have found nearly 50,000 meteorites in Antarctica, and hundreds of thousands are still waiting to be discovered.
03:53Each of these space rocks can tell us a story about the evolution of the solar system.
03:58For example, the very first lunar rock found on the frozen and desert continent
04:03confirmed the fact that pieces of space objects larger than asteroids could be found on Earth.
04:08Let's imagine that you are inspired and that you decide to go hunting for meteorites in Antarctica.
04:14Get ready to take on serious challenges.
04:17Despite their potential abundance, finding space rocks is not as easy as it seems.
04:23You will have to go to remote areas, and it is not even certain that you can find anything.
04:29It is also a very big problem. Meteorites are disappearing.
04:35Currently, scientists find about 1,000 meteorites a year in Antarctica.
04:40But according to a new study, about 5,000 meteorites would disappear every year.
04:45The cause is rising temperatures.
04:48Worried, researchers have created a model capable of helping them determine where these meteorites are likely to rise to the surface.
04:56This model is quite complex, because it takes into account the snow cover,
05:01the surface temperature, the speed of ice melting, and even the inclination of the terrain.
05:07Scientists then carried out simulations in the context of different warming scenarios.
05:13And it turned out that the meteorites were actually sinking as the temperatures increased.
05:19The surprise of the researchers is obvious.
05:21They did not expect that climate change would affect their work so much.
05:26Even if these regions are below freezing point,
05:29our way of life contributes to the destruction of a crucial archive of the solar system.
05:34But let's go back to your hunt for meteorites.
05:37If you want to increase your chances of finding one,
05:40go to the foot of the mountains where the ice, which usually flows down, is forced to rise.
05:46And do not forget to bring your windbreaker.
05:48In these places, powerful winds sweep the snow exposing a blue ice.
05:53Instead of melting, this old ice can directly turn into water vapor.
05:58And this is how we can discover meteorites that otherwise would remain hidden.
06:03But we must hurry.
06:05Meteorites on the surface disappear quickly.
06:09Even when the temperatures are much lower than freezing point,
06:13the rocks can still absorb some of the heat of the sun and melt the ice.
06:18It is as if they were creating underground tunnels or underglaciers,
06:22sinking and collapsing in front of everyone.
06:25Some time later, the ice closed the entrances of these tunnels,
06:29imprisoning the meteorites and making any discovery impossible.
06:34Scientists admit that it is very difficult to find effective methods to locate meteorites.
06:40And if we do not hurry to develop good techniques,
06:44we risk losing between 80,000 and 250,000 space rocks in total.
06:50It is therefore not surprising that scientists have given themselves the mission to find more meteorites.
06:56They focus on the collapse zones.
06:59These are places where meteorites accumulate on the surface
07:02due to the geological characteristics of the ice flow and climatic conditions.
07:08As you already know, you can find meteorites on blue ice without snow cover.
07:14Meteorites are therefore easy to locate.
07:17But finding these hot spots is often pure chance.
07:20Or you have to spend whole days peeling maps and satellite images
07:25to try to locate the blue ice zones near the research stations.
07:30Let me introduce you to Véronika Tolénar, training glaciologist and her team.
07:36They went faster by developing an intelligent map of Antarctica.
07:41To do this, they used automatic learning and satellite data from NASA,
07:46the Canadian Space Agency and other organizations.
07:49This map highlights the areas where meteorites could be hidden.
07:54On the basis of previous discoveries and all kinds of data related to climate and ice.
08:00Apparently, the best places to find meteorites are on the shores of the continent
08:05and near the mountains covered with blue ice.
08:08Unfortunately, there is not only blue ice that matters.
08:11The temperature and the speed of ice flow are also very important.
08:16For example, if the ice flows too fast,
08:19meteorites are carried away before they can accumulate.
08:23If you want to find a meteorite, you need very precise conditions.
08:27The surface temperature must remain below minus 9 degrees Celsius almost all the time.
08:32Otherwise, the meteorites flow.
08:35You can start looking near the hills of Alan.
08:38Yes, this is where our friend ALH was discovered.
08:41This region is a kind of gold mine for meteorites, with more than a thousand discoveries.
08:46But there are even more promising places,
08:49like the mountains of Fimbulaymen, where no one has done research yet.
08:53You may be the first.
08:56Anyway, thanks to this new map,
08:59researchers have developed a ranking of the best places to hunt for meteorites,
09:03which will better target future outings on the ground.
09:07And as many regions of blue ice are still unexplored,
09:10there are tons of meteorites waiting for you to be discovered.
09:14So, what are you waiting for?