Les scientifiques ont remarqué quelque chose d'étrange à propos de Pluton et de sa grande lune, Charon, et cela les amène à reconsidérer beaucoup de choses ! Contrairement à la plupart des lunes, Charon fait presque la moitié de la taille de Pluton, si bien qu'elles gravitent autour d'un point dans l'espace situé entre elles, presque comme si elles étaient des planètes jumelles. En plus de cela, Pluton possède un "cœur" rougeâtre et Charon a un "capuchon" sombre à son pôle, deux éléments qui sont inhabituels et restent encore quelque peu mystérieux. La couleur rouge sur Pluton provient de substances chimiques appelées tholines qui se forment lorsque la lumière du soleil frappe des gaz, mais pourquoi Charon a cette tache sombre déroute encore les scientifiques. De plus, Pluton et Charon présentent toujours la même face l'un à l'autre, une face de Pluton ne voit donc jamais sa lune ! Ce système unique donne aux chercheurs une multitude d'indices sur la façon dont les petites planètes et lunes se forment et évoluent au fil du temps. 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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00:00Pluto was once considered a major planet, but it was then classified in the category of dwarf planets,
00:07that is to say something too big to be an asteroid, but too small to be taken seriously.
00:13Not very nice.
00:14Recently, scientists have begun to discuss the mystery surrounding one of Pluto's moons.
00:20It turns out that it could be even cooler than we thought.
00:23We could have a system with two planets there.
00:26Pluto resides in the distant belt of Kuiper, a vast area of our solar system,
00:34like a large rocky banlieue located beyond the orbit of Neptune.
00:38It is filled with small icy objects, similar to Pluto, and bearing the name of Kuiper objects.
00:44These objects are the remains of the first days of our solar system,
00:48and they give us some clues about how it was formed.
00:51It is from there too that many comets come from.
00:54You already knew it was small, but did you know how much?
00:58Pluto has a width of about 2,250 km,
01:02about half that of the United States, and much smaller than our moon.
01:06Pluto's atmosphere is very fine, and is composed of nitrogen, methane, and carbon monoxide.
01:12A real treat for the nostrils.
01:14And it is also very cold, with average temperatures of about minus 234 ° C.
01:21Its orbit around the sun looks like an oval, and a year on Pluto lasts about 250 terrestrial years.
01:28Pluto also has a strange and unique retrograde rotation,
01:32because it is tilted on its axis, which means it turns to the side.
01:38If you were on Pluto, you would be surrounded by high icy mountains, valleys, plains, and craters.
01:45The sun would be very weak and distant, it would always be twilight.
01:49It is a very colorful planet, surprisingly.
01:51You would see a rainbow of pale blue, yellow, orange, and deep red.
01:56But the most adorable about Pluto is its famous heart, the Tombaugh region.
02:00Pluto was discovered very late, in the 1930s, much later than the other planets.
02:06At first, we thought it was the ninth planet in our solar system.
02:11However, the more we explored Kuiper Belt,
02:15the more we realized that it was filled with these medium-sized objects.
02:19We found four other small planets similar to Pluto.
02:22Eris, Ceres, Makemake, and Aumea.
02:26They all had the same characteristics.
02:29It was at this moment that we understood that Pluto belonged to a completely different family,
02:33and that we had created the category of dwarf planets.
02:39There are some differences between these two categories of planets.
02:42The first obvious difference is the size and mass.
02:45The major planets are much larger and more massive.
02:48They must also be spherical, while dwarf planets cannot be perfect spheres.
02:54They can have weird shapes, like Aumea, which is shaped like an egg, for example.
02:59Just like a normal planet, a dwarf planet rotates around the sun, but its orbit is not clear.
03:05It is full of debris and heteroclite objects.
03:08These are the only differences.
03:09This reclassification has therefore aroused a lively controversy.
03:13The English speakers have even invented a new term,
03:16to be plutoed, which means to be outclassed.
03:19Although it is sad that Pluto is no longer a major planet,
03:22we can console ourselves by telling ourselves that we have found a real family for it.
03:29Finally, when you stand on Pluto, you can see its five moons,
03:34Styx, Nix, Kerberos, Hydra, and the most mysterious, Charon.
03:39Charon is Pluto's largest moon.
03:41It was discovered in the 1970s thanks to NASA's New Horizons probe.
03:46The probe took a photo that revealed a moon with a fascinating and huge red-brown spot on its surface.
03:52It is a vast canyon that has nothing to envy to our Grand Canyon.
03:56It seems that Pluto and its moon both have interesting formations on their surface.
04:02Charon's particularity is that it is very large for a moon.
04:05It is about half the size of Pluto.
04:07Scientists therefore wonder, would Pluto be a two-planet system?
04:12The center of mass, or barycenter, of Pluto and Charon is outside Pluto.
04:18Normally, in the case of planets and their moons,
04:21it is the center of the planet itself that should be the center of mass, the moon orbiting it.
04:27But in the case of these two objects, it seems that they orbit each other.
04:31Binary objects are very common in the universe.
04:35These cosmic couples form as our moon formed, as a result of a giant impact.
04:40But double planets are extremely rare, and we have never discovered double dwarf planets.
04:46If the hypothesis is confirmed, it would mean that Charon is in fact the sixth dwarf planet.
04:51It will then be the first binary system of dwarf planets in history.
04:55But we have another candidate, the dwarf planet Eris and its moon, Dysnomie.
05:02The solar system is full of mysterious and fascinating moons.
05:07So fascinating that some of them could even be home to life.
05:11It's been a while since we've talked about microscopic life in space.
05:15Debates about the discovery of organic fossils on Mars have been going on for decades.
05:20With the development of our technology, we are finally on the right track.
05:24Here is Encelade, very popular since the arrival of the Cassini probe from NASA.
05:29Encelade is covered with a kind of snowy coat,
05:32which explains its unusual brightness and the presence of snowy craters.
05:36It is small, only about 500 km, and is mainly composed of rocks and ice.
05:42But in 2004, we discovered panaches of water spilling into the south pole of this moon.
05:47This means that there is liquid water under its icy surface.
05:51The reason is probably Saturn and its other big moon, Dione.
05:56Their gravitational dance creates tidal forces that bring heat and life to Encelade.
06:00Encelade is therefore a candidate for choice in the search for life in our solar system.
06:04Of course, life requires more than water, and we will not find animals or anything of the kind.
06:10But we could find microscopic organisms there.
06:13And that's really great.
06:17In fact, Saturn is winning the lottery in terms of the possible presence of life forms.
06:23For example, scientists had the crazy idea that Titan, another of these moons,
06:28could also shelter an extraterrestrial life.
06:31Titan is an icy satellite whose temperature is close to minus 179 degrees Celsius.
06:36Surprisingly, there are even lakes on its surface.
06:39But don't imagine classic water expanses.
06:42These lakes would not be filled with water, but with tannins or liquid methane.
06:46In 2005, NASA mentioned the possibility of a life feeding on chemical substances
06:52such as acetylene or hydrogen in the Titan lakes.
06:56Then, in 2010, NASA scientists went deeper into their research.
07:01And they discovered that there was a lack of hydrogen and acetylene in the Titan lakes,
07:06which suggests the possibility that something feeds on these substances.
07:10As a result, some dared to imagine methane-eating beings in the frozen lakes of Titan.
07:15In addition, they suggested that, if these creatures exist,
07:19they probably have cells much larger than those of terrestrial animals.
07:23So we could find there something much bigger than a simple microbe.
07:27Something like a small animal, for example.
07:31But Saturn is not the only one to be lucky.
07:34Triton is Neptune's big moon.
07:36And you guessed it, it's another candidate.
07:39The surface of this icy world is covered with nitrogen and its crust is made up of water ice.
07:44Once again, it is very cold there.
07:46And Triton is one of the favorite of geologists.
07:49Because it is part of the small number of moons that, in our solar system,
07:53have formidable active geysers.
07:56They reject gaseous nitrogen into space.
07:58It would be a beautiful spectacle if we could see it.
08:01These geysers mean that Triton has a secret source of heat.
08:05This means that, just like for Encelade, there could be liquid water under the surface of Triton.
08:10And if this place turns out to be home to life, we could find organic substances there.
08:18Unfortunately, it is not easy to send a mission to explore these celestial bodies.
08:22The only spacecraft we have sent so far is Voyager 2, in 1989.
08:29It takes us more time, money and technology to develop probes capable of traveling far
08:34and exploring the regions located beyond Mars.
08:37And even if we get there, it will take decades for these machines to reach these places.
08:42Anyway, let's hope that in the 21st century,
08:46we will finally be able to fully explore our solar system and all its wonderful mysteries.