Les Objets les Plus Rares à Avoir Visité Notre Système Solaire

Sympa

Notre système solaire a reçu des visiteurs vraiment rares. Oumuamua a été le premier objet interstellaire connu à traverser notre système solaire, et les scientifiques pensent qu'il pourrait s'agir d'un astéroïde de forme étrange ou même d'un morceau de planète brisée. Puis, il y a la comète Borisov, une autre voyageuse interstellaire qui nous a donné un aperçu de ce à quoi ressemblent les comètes des autres systèmes solaires. L'astéroïde 514107, également connu sous le nom de Kaʻepaokaʻāwela, a une orbite inversée inhabituelle autour du soleil, probablement parce qu'il a été capturé depuis un autre système stellaire. Plongeons dans leur monde inhabituel !  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

00:00The solar system is full of mysterious objects from everywhere.

00:05In October 2017, researchers from Hawaii discovered a strange object they called Umuamua,

00:12meaning a visitor from a distant land, in Hawaiian.

00:16Or it's the burrowing of a very big cow.

00:19It followed an escape orbit, literally escaping the gravitational attraction of its planet,

00:24as if it was thrown a ball into space without any hope of return.

00:28This means that this unusual object comes from the outside of our solar system.

00:33The theories about it were numerous, from a simple asteroid to an alien spaceship.

00:40Some scientists have even considered that it is a piece of nitrogen ice,

00:45coming from a planet similar to Pluto.

00:47Its unusual shape only adds to the mystery.

00:50The significant variations of its luminous curve

00:53suggest that this object could be either elongated, like a tube,

00:57or flat, like a pancake.

00:59This object was unique in its kind.

01:01Umuamua did not behave like a comet or an asteroid.

01:05Comets, composed of ice, develop shiny tails as they approach the sun,

01:10while asteroids, mainly made of rocks, have no tails.

01:15Umuamua has no tail and does not release gas, but it is not a simple rock either.

01:20Its surface is very shiny, almost like polished metal.

01:23When it passed near the sun, its speed suddenly increased,

01:27as if it had been propelled by a rocket.

01:29And it was not the gravity of the sun that caused this sudden acceleration.

01:33Scientists do not know what caused it.

01:36So, what was this object really?

01:39After years of study, scientists now estimate that Umuamua

01:43is probably a comet covered with frozen hydrogen.

01:46This hydrogen reacted with the light of the sun,

01:49accelerating the comet and changing its trajectory.

01:52Umuamua probably accumulated this hydrogen

01:55by being exposed for a long time to cosmic rays.

01:58It also acquired a nice red tint thanks to this exposure.

02:02This object was a visitor from a young chaotic solar system,

02:06where collisions and migrations are frequent.

02:09Such systems often propel many small objects.

02:13It is possible that it was ejected by a planet such as Jupiter,

02:17whose gravity is so intense that it can project huge objects through space.

02:22This phenomenon also occurs with the comets we observe.

02:26Umuamua has already left our solar system,

02:29although similar objects visit us from time to time,

02:32about once a year.

02:34To learn more about these mysterious visitors,

02:37astronomers plan to send a probe in pursuit of Umuamua.

02:40We will use the orbits of Earth and Jupiter

02:43to accelerate it enough to catch up with it.

02:46However, some visitors have stayed a little longer in our neighborhood.

02:50In October 2019, the Hubble Space Telescope

02:53captured the image of a bluish comet,

02:56surrounded by dust and gas.

02:58At that time, it was already in our solar system,

03:01about 420 million kilometers from Earth,

03:04somewhere between Mars and Jupiter.

03:07We were able to observe the luminous dust surrounding it,

03:10but its core was still invisible due to its small size.

03:13However, small and relative here,

03:16this comet is about 1,000 meters wide,

03:19the length of 10 football fields.

03:21In March 2020, Hubble images revealed

03:24that a small fragment had detached from the core,

03:27indicating that this comet is very active, unlike Umuamua.

03:30By examining the object more closely,

03:33we discovered that its core was a mixture of ice and dust particles.

03:37Its surface is also similar to that of other comets,

03:40with rough areas and smooth layers of icy and dusty debris.

03:44This comet was discovered by the amateur astronomer

03:47Gennady Vladimirovich Borisov,

03:49and was therefore nicknamed Comet 2i Borisov.

03:52Scientists have quickly confirmed

03:54that it came from outside our solar system.

03:57This comet was like a tourist enthusiast.

04:00It was moving at a dizzying speed of about 180,000 km per hour.

04:04Such a speed would allow to go around the Earth 4 times in an hour.

04:09But this visit was fascinating for many other reasons.

04:13Most of the comets in our solar system

04:16come from the Quipper Belt or the Oort Cloud.

04:19The Quipper Belt is a region of space beyond the orbit of Neptune,

04:23similar to a large distant ring around the Sun,

04:26and filled with many icy objects.

04:29They are all ancient remains of the time

04:31when our solar system was still very young.

04:34The Oort Cloud is much further away.

04:37It forms a gigantic bubble around the solar system,

04:40also filled with very ancient icy objects.

04:43Most long-term comets come from there.

04:46But where does Comet 2i Borisov come from?

04:49We still do not know for sure.

04:52Scientists estimate that it could have been formed in another stellar system,

04:56which could be either younger or older than ours.

05:00NASA had accustomed us to more precision.

05:03In any case, it is possible that it was expelled from its original system,

05:07just like the summer or the month of May.

05:11Although Comet 2i Borisov is too small to maintain its own

05:15to maintain its own

05:17to develop a hair when it approaches the Sun.

05:20The term hair

05:22refers to this magnificent cloud of luminous gas and dust

05:25that surrounds the core of the comet.

05:28It is formed when the heat of the Sun causes the vaporization of the ice that is there.

05:32Thus releasing dust and gas into space.

05:35This comet was more friendly than Oumuamua

05:38and allowed us to study it more.

05:41We have thus discovered interesting characteristics,

05:44such as the fact that it had never interacted with another star, for example.

05:47Unfortunately, Borisov also had to leave us.

05:50It is now on a path that will take it back to interstellar space.

05:54Nevertheless, other visitors are approaching us.

05:57And you may have heard of this one.

06:02The Great Comet of 1996.

06:05This is how we nicknamed the Hyakutake Comet.

06:08It was also named after the astronomer Yuji Hyakutake

06:12who discovered it, by an incredible coincidence,

06:15on the eve of the New Year.

06:17On March 25, 1996,

06:19this object passed incredibly close to Earth.

06:22Barely 0.1 astronomical unit,

06:25a little further than the Moon.

06:27It flew over the North Pole,

06:29making this interview one of the closest

06:31with a comet of the last 200 years.

06:34Visible all over the world,

06:36it was very bright and spread widely in the sky.

06:39And it did not stop being visible for a single night.

06:42It became more and more apparent during the month of March,

06:46ranking among the brightest objects in the night sky at the end of the month.

06:50It completely disappeared at the end of May.

06:53It is a long-term comet,

06:55which means it takes hundreds of years

06:57to orbit around the Sun.

06:59The last time it visited us

07:01was about 17,000 years ago,

07:03but its orbital period has now increased

07:05to 70,000 years.

07:07But do not worry,

07:09other comets will illuminate our days and nights.

07:11In addition, some space objects

07:13prefer to take longer.

07:16Then comes this asteroid,

07:18Ka-Hepaoka Auella.

07:20You will excuse me if I misspell the name.

07:22In Hawaiian,

07:24it means Jupiter's mirror.

07:26Fortunately, the scientists

07:28had the kindness of naming it BZ

07:30to facilitate the life of your friendly narrator.

07:33It is a small asteroid,

07:35about 2.9 km in diameter.

07:37As its name suggests,

07:39it shares an orbit with Jupiter.

07:41But here is a fascinating detail.

07:43This asteroid moves in the opposite direction,

07:46what is called a retrograde orbit.

07:49This unusual asteroid

07:51was discovered in November 2014.

07:53It orbits around the Sun

07:55for about 11 years and 8 months,

07:57sometimes going inside

07:59and outside the orbit of Jupiter.

08:01It has been like this for at least 1 million years,

08:04and it will continue like this

08:06for another million years.

08:08But why does it move so uniquely?

08:10BZ could well be

08:12an interstellar vagabond.

08:14Maybe it passed through our solar system

08:16about 4.5 billion years ago,

08:18when the Sun was formed.

08:20Then, it would have been captured

08:22by its gravity,

08:24keeping an opposite orbit.

08:26Or maybe it comes from the cloud of Oort.

08:28In this case,

08:30it could have inherited its strange orbit

08:32of the mysterious new planet.

08:34A hypothetical body,

08:36whose existence is suspected

08:38in our solar system,

08:40far beyond Neptune.

08:42Whatever it is,

08:44this asteroid offers us

08:46a precious insight into the history

08:48of the solar system

08:50and the way in which organic matter

08:52comes from distant space.

08:54They stay there for variable periods of time.

08:56But sometimes, we are lucky,

08:58and they teach us a lot

09:00about the space around us.

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