00:00A few years ago, the NASA observed a strange blue light on Jupiter.
00:06It quickly fell and failed to pass in a way.
00:09Would this be a proof that the gas giant cave cache
00:12the phenomena that we ignore since decades?
00:15And if it is the case,
00:16what would be the implications for us, on Earth?
00:19In reality, the astronauts did not discover this phenomena by chance.
00:24Jupiter has been object of attentive observations for long time,
00:27especially thanks to the Juno mission.
00:31The Juno mission was launched in 2011
00:33and reached Jupiter in 2016.
00:37Since this date, she orbit around the planet
00:39and recueil a large quantity of data.
00:42Her mission consists of better understanding
00:44the composition of Jupiter,
00:46the function of its atmosphere
00:48and the processes to work in its depths.
00:51In 2020, one of its cameras, the JunoCam,
00:54a very inspired name,
00:56a recorded something habituel.
00:59Près du pôle Nord de Jupiter,
01:01a brief light light very luminous is appeared.
01:03This phenomenon seemed to be moving,
01:06and at a remarkable speed.
01:08Or, capture of rapid objects in space
01:10is particularly hard,
01:12which explains the surprise
01:13of many researchers face this image.
01:16So, what would be this lueur?
01:18The explanation the most plausible
01:20and the most widely admised
01:22is that of an eclair.
01:23But the eclair Joviens
01:24differ very strongly
01:25from those of the Earth.
01:27Sur this planet,
01:28they form at the interior
01:29of immense nuages
01:30composed of ammonium and eau.
01:32The tempest who reign
01:34are much more violent
01:35than those observed at us
01:36and can produce
01:38the teintes inhabituelles,
01:40like the ver.
01:41But if this lueur
01:42was not an eclair,
01:43why did we never see it?
01:45It is possible
01:47that she exists for a long time,
01:48but that she moves too fast
01:50to have been captured
01:51by our instruments
01:52until then.
01:53If she was observed
01:54again,
01:55the researchers
01:55could analyze it
01:56more precisely
01:57and determine the nature.
01:59In the meantime,
02:00most of the explanations
02:01remain based
02:01on our current knowledge
02:03today.
02:04Another question
02:05is to know
02:06what this trouvaille
02:07could mean for the Earth.
02:09The savants
02:10think that she has
02:11no effect direct
02:12on our planet.
02:13But the discovery
02:14remains important.
02:15because it confirms
02:16that the phenomena
02:17comparable
02:18to the earth
02:19like the fudre
02:20exist on other planets,
02:22sometimes
02:23even more extreme shapes.
02:25Like on Mars,
02:26for example.
02:27The scientists
02:27have discovered
02:28that the atmosphere
02:29of the planet
02:29has decreased
02:30of electricity.
02:31Otherwise,
02:32Mars has
02:33few clouds.
02:35In 2021,
02:36when the snowstorm
02:37is passing on the
02:38rover Perseverance,
02:40the researchers
02:41were waiting
02:41to hear the usual noise
02:42of the sky.
02:44which falls
02:44and the wind
02:45which falls.
02:46However,
02:47the rover
02:48has captured a light
02:49pop.
02:50At the moment,
02:51it was difficult to explain.
02:53But at the moment,
02:55the researchers
02:55think they have understood
02:56its origin.
02:57This noise
02:58would come from
02:58an electric charge
02:59in the air
03:00very tense.
03:01In sum,
03:02a mini-clair martian.
03:04It doesn't look
03:05as a solar light.
03:06No big flash
03:07does not traverse
03:08the sky.
03:08The atmosphere
03:10is too fine
03:11for this.
03:11It's rather
03:12a minuscule
03:13enticelle.
03:14It counts
03:15as a fad
03:16which is officially
03:17the third planet
03:19known
03:19in Mars
03:20after Jupiter
03:22and Saturne.
03:24How the researchers
03:25have discovered
03:25Perseverance
03:27has a microphone
03:29called Supercam.
03:30During two years,
03:32he recorded
03:33about 28 hours
03:34of his Mars.
03:34In this data,
03:36there were 55
03:37breves
03:38impulsions
03:38correspondant
03:39to the little
03:40electric charge
03:40electric.
03:41They were infamous
03:43compared to the little
03:44electric charge
03:45when you touch
03:46a door
03:47after walking
03:48on a tree.
03:49Each
03:50has lasted
03:51a few milliseconds.
03:53But
03:53seven of them
03:54also
03:56interferences
03:57electromagnetic
03:57important
03:58showing that
04:00electricity
04:00had been
04:01in the air
04:01close to the rover.
04:03But
04:03d'où
04:03comes this
04:04martian?
04:05Sur Terre,
04:06the clouds
04:07nest in the clouds
04:08when particles
04:09of ice
04:10come out.
04:11Mars
04:12has not
04:13a cold
04:13and too cold
04:16and too cold.
04:17However,
04:18the planet
04:19is very
04:19icy.
04:20When the clouds
04:21agitate
04:22the clouds
04:23of ice
04:23and exchange
04:26electric charges
04:27the scientists
04:29use
04:29for this
04:30a long
04:31and complex
04:32the
04:32tribo-electrification.
04:34The idea
04:34remains simple.
04:36The frotting
04:36accumulates
04:37the electricity.
04:38When the charge
04:39becomes quite
04:40strong,
04:40it is free.
04:41This charge
04:42produces both
04:43a sound
04:44and
04:44the same
04:46signals
04:46detected
04:47by
04:47Perseverance.
04:48This
04:49can
04:50seem
04:50anodine
04:51but
04:51they
04:51are
04:51important.
04:53The
04:53electric
04:53could
04:54improve
04:54the
04:55power
04:55of
04:55the
04:55could
04:56help
04:57the
04:57electric
04:57could
04:58the
04:58of
04:58the
04:58of
04:58hydrogen
04:59and
05:00the
05:00hydrogen
05:00can
05:01cause
05:01the
05:02energy
05:02could
05:04also
05:05influence
05:08the
05:10power
05:13of
05:13of
05:14of
05:15the
05:15power
05:15of
05:16the
05:17power
05:20of
05:22so
05:22more
05:23more
05:23the
05:23could
05:29perturb
05:30our
05:31systems
05:31or
05:32could
05:34make
05:35the
05:37to
05:38create
05:39the
05:39spacecraft
05:41to
05:43in
05:44the
05:44environment
05:44of
05:45Mars.
05:46Now
05:48we
05:48move
05:49into
05:49the
05:49solar
05:49new
05:50simulations
05:54indiquent
05:55that
05:56Uranus
05:56and Neptune
05:57would not be
05:58gigantic
05:58glass.
06:00Their interior
06:01could only be
06:01fine
06:02of
06:03scientists
06:06could
06:07correspond
06:10without
06:11the
06:12without
06:12being dominated by
06:13the
06:13glace.
06:14In
06:14several
06:15simulations,
06:16planets
06:16contiennent
06:16even more
06:17more
06:17of
06:17the
06:17rocks.
06:18with
06:19the
06:19current
06:20Uranus
06:21and
06:21Neptune
06:21could
06:22be rich
06:22in
06:23rocks
06:23and
06:23glace.
06:24The
06:25scientists
06:25are always
06:29able to
06:31be able to
06:32study
06:32the
06:36sonde
06:37Voyager 2
06:38a
06:38survolé
06:38Uranus
06:39en 1986
06:40puis
06:41Neptune
06:41en 1989.
06:43Elle a recueilli quelques mesures avant de poursuivre sa route.
06:47Aucune sonde n'est restée assez longtemps pour comprendre réellement ce qui se passe sous les nuages.
06:52Les chercheurs doivent donc s'appuyer sur des simulations construites à partir d'indices limités.
06:58L'image classique des géantes de glace reste valable, mais ce n'est plus la seule interprétation compatible.
07:05Une autre découverte remarquable concerne Ariel, une lune d'Uranus.
07:09Bien que petite, les scientifiques pensent aujourd'hui qu'elle aurait pu abriter un immense océan souterrain représentant plus de
07:16la moitié de son volume.
07:17Cet océan aurait pu atteindre environ 170 km de profondeur et aurait peut-être existé il y a seulement 1
07:24milliard d'années.
07:26Ariel ne mesure qu'environ 1 100 km de diamètre, soit à peu près un tiers de la taille de
07:31la Lune.
07:31Pour cette raison, on pensait autrefois qu'elle ne pouvait pas conserver sa chaleur très longtemps.
07:37Des recherches plus récentes nuancent cette idée.
07:40Lorsque Voyager 2 est passé près d'Uranus en 1986, elle a renvoyé des images montrant que la surface d
07:46'Ariel n'avait pas l'aspect ancien et figé attendu.
07:49La Lune paraissait plutôt jeune et active, avec des fissures, des crêtes et même des signes de volcans glaciaires.
07:57Certaines structures rappellent dit fortement celles observées sur Europe, Encelade ou Triton, des mondes où l'on sait déjà que
08:03des océans existent sous la glace.
08:06Par la suite, les scientifiques ont aussi détecté sur Ariel des traces d'ammoniaque et de composés carbonés.
08:12Ces substances disparaissent normalement assez vite, sauf si quelque chose les fait remonter depuis l'intérieur, ce qui suggère souvent
08:19la présence d'eau liquide souterraine.
08:21Les chercheurs ont donc élaboré des modèles de la structure interne possible de la Lune.
08:27Dans ces simulations, Ariel possède une croûte externe fragile, une couche plus souple en dessous, puis un océan profond, et
08:35enfin un noyau solide.
08:37Ils ont ensuite étudié la réaction de cette croûte aux forces de marée, provoquée par l'attraction d'Uranus et
08:43des autres lunes.
08:45Les calculs montrent que si la croûte faisait moins de 30 km d'épaisseur, elle pourrait se fissurer sous une
08:52forte contrainte de marée.
08:54Une telle contrainte aurait pu provenir d'une interaction avec la Lune Miranda il y a environ 1 à 2
08:59milliards d'années.
09:00Cette interaction aurait légèrement modifié l'orbite d'Ariel et exercé une tension suffisante pour fracturer sa croûte.
09:07Quoi qu'il en soit, il est trop tôt pour affirmer qu'Ariel possède aujourd'hui un vaste océan.
09:13Elle est si petite qu'elle perd facilement sa chaleur.
09:16Et si de l'eau liquide y subsiste, il doit y en avoir très peu.
09:20Ce ne serait probablement pas l'endroit idéal où rechercher la vie.
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