Les astronomes viennent de découvrir une planète qui pourrait être parfaite pour la vie humaine ! Elle se trouve dans la "zone de Goldilocks", ce qui signifie qu'elle n'est ni trop chaude ni trop froide—juste ce qu'il faut pour de l'eau liquide. Les scientifiques pensent que cette planète pourrait avoir une atmosphère, des océans et peut-être même déjà de la vie. Elle est très éloignée dans l'espace, mais avec les nouvelles technologies, nous pourrions en apprendre davantage bientôt. Imaginez un avenir où les humains pourraient y voyager et commencer une nouvelle vie parmi les étoiles ! Pour l'instant, tout ce que nous pouvons faire, c'est continuer d'explorer et de rêver à ce qui se trouve là-bas. Animation créée par Sympa.
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Musique par Epidemic Sound https://www.epidemicsound.com
Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna
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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
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Si tu en veux encore plus, fais un tour ici:
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FunTranscript
00:01Look at this fascinating planet.
00:03It looks like a prey to flames.
00:05Its surface must be even more burning than the heart of the Valley of Death.
00:09The ground, arid and cracked by huge cracks,
00:13shows an absolute dryness.
00:17Not a single drop of water exists in this overheated universe.
00:20Yet, here is the same planet under a completely different face.
00:23Now, it is plunged into a glacial cold.
00:27The temperatures there are so low that any form of life would be strictly impossible.
00:33This singular world, called HD 2794D,
00:37is located at 19.7 light years from Earth,
00:41within the constellation of Eridan.
00:43It is a super-Earth,
00:45that is to say, a planet more massive than Earth,
00:48but more modest than glacial giants like Neptune.
00:51What distinguishes it is its atypical orbit,
00:54which sometimes makes it penetrate, sometimes leaves the habitable zone of its star.
00:59This region, where the conditions of temperature
01:01could allow the presence of water in liquid form.
01:05However, this intriguing planet has never been observed directly.
01:09Astronomers detected it by analyzing tiny oscillations of its star,
01:14thanks to two high-precision instruments,
01:16ESPRESSO and HAPS,
01:18installed on telescopes in Chile.
01:20These tools measure radial speed,
01:23that is to say, the slight movements of the star caused by the gravitational attraction of the planet.
01:28The more this oscillation is marked,
01:30the more the planet that is at the origin of it is massive.
01:35By exploiting these data,
01:36researchers have determined that this planet had a mass about 6 times higher than that of Earth.
01:42It gravitates around a star, HD 2794,
01:47also known as 82G.
01:50Eridani, slightly smaller and less luminous than our sun.
01:54What makes it unique is that it is bright enough to be visible to the naked eye,
02:00unlike many other stars housing exoplanets,
02:04that it is impossible to see without a telescope.
02:07This system has been under surveillance for more than 20 years.
02:11For a long time.
02:12Scientists suspected that it sheltered several planets,
02:15and in 2011, they confirmed the presence of two super-Earths,
02:19HD 2794D and HD 2794C,
02:24respectively making a revolution around the star in 18.3 and 89.6 days.
02:32For a while, a third planet,
02:34whose orbital period was estimated at 40 days,
02:37seemed to have been detected.
02:39Researchers began to doubt it,
02:41but after the thorough re-evaluation of several years of data,
02:45they ended up validating its existence.
02:47This is the extreme HD 2794D.
02:54Michael Kretinier, a researcher at the University of Oxford,
02:57played a decisive role in identifying this planet.
03:01He relied on an IT algorithm called Yarrara
03:05to isolate the low signal of the planet from the background noise.
03:08Thanks to this method,
03:10he was able to confirm not only the existence of HD 2794D,
03:16but also its exceptional character.
03:18Unlike the planets of our solar system,
03:21which follow essentially circular trajectories,
03:24this one adopts a strongly elliptical and elongated orbit.
03:29It takes 647 days to complete a revolution around its star,
03:34which is 40 days less than the duration of the Martian orbit around the Sun.
03:38At its apex, this planet is at a distance
03:41equivalent to twice the Earth-Sun interval,
03:43placing it well beyond the habitable zone.
03:46But at its perigee, it approaches up to 0.75 UA,
03:51penetrating then into the region
03:53where temperatures could allow the presence of liquid water.
03:56This extreme oscillation generates strange seasons.
04:00During a part of its orbit,
04:02HD 2794D turns into a real desert of ice.
04:08As the planet approaches its star,
04:10temperatures rise,
04:12and the ice must then melt,
04:14giving birth to ephemeral oceans.
04:16It thus goes through a brief period of torrid heat,
04:19so intense that water on the surface could evaporate into the atmosphere.
04:23But as soon as the planet moves away,
04:25a misty autumn sets in, accompanied by rain,
04:28before giving way to a harsh winter.
04:32In other words, this planet is also between extreme cold and overwhelming heat,
04:37making its environment unpredictable for any form of life.
04:41If organisms have developed there,
04:43they must necessarily be able to resist an environment in perpetual upheaval.
04:48But why is HD 2794D such a singular orbit?
04:54It could be the remains of events that occurred billions of years ago,
04:58while the planetary system was still in formation.
05:02At a later time,
05:04another planet of size could have disturbed its orbit,
05:07imposing this trajectory on it.
05:09Another theory suggests that a giant planet once present in the system
05:13would have forced HD 2794D to follow an elongated orbit
05:18under the effect of its gravitational influence.
05:21Later, this giant could have been expelled from the system,
05:25abandoning HD 2794D on its current trajectory.
05:30This theory seems coherent,
05:32because the two other planets in the system,
05:34HD 2794B and HD 2794C,
05:39evolve on much more regular orbits.
05:42The discovery of this planet is fascinating,
05:45because it questions our understanding of living worlds.
05:49Unlike the planets that permanently reside in the habitable zone,
05:53HD 2794D only crosses it.
05:57Scientists want to know if it could still shelter life,
06:01if only temporarily.
06:03To answer this question,
06:05future telescopes will analyze its atmosphere
06:07in search of water, gas, or even biological traces.
06:13Another super-Earth likely to shelter life
06:15evolves around a star located 137 light-years away.
06:19In astronomical terms, it is relatively close.
06:22A light-year is equivalent to about 9.5 billion kilometers.
06:26Named Toei 515b,
06:28this planet is once and a half larger than Earth,
06:31and, unlike HD 2794D,
06:35it remains permanently in the habitable zone.
06:38Look, here's what astronomers think this planet could look like.
06:43Toei 515b loops its orbit very quickly,
06:46in just 19 days.
06:48But although it is close to its star,
06:50it could not be excessively hot,
06:52because its star is a red dwarf,
06:55a celestial body smaller and colder than our sun.
06:58This means that Toei 515b could have a warmer climate
07:02than other exoplanets orbiting warmer stars.
07:07NASA detected this planet
07:09thanks to the Satellite Transiting Exoplanet Survey,
07:12which detects exoplanets by observing
07:14the slight decrease in brightness of a star
07:16when a planet passes in front of it.
07:18As red dwarfs are smaller and less bright than the sun,
07:22transiting planets are easier to identify.
07:26Astronomers plan to study this planet
07:28through the James Webb Space Telescope.
07:32Located 1.6 million kilometers from Earth,
07:35this ultra-performing telescope
07:37is able to analyze the atmosphere of exoplanets.
07:40If Toei 515b has one,
07:43it could help researchers identify the gases present
07:46and evaluate whether the conditions are conducive to liquid water,
07:49or even to life.
07:52Another promising world in our extraterrestrial life quest
07:55is an ultra-dense super-Earth of the K2-360 system.
07:59An international team of Japanese and European researchers
08:02identified this planetary system in orbit
08:04around a star similar to the sun,
08:06750 light years away.
08:08This system contains two planets,
08:10including one of the densest rock exoplanets ever discovered.
08:14K2-360b is a rock super-Earth,
08:17measuring about 1.6 times the size of Earth,
08:21but with a mass 7.7 times greater,
08:24which makes it as dense as lead.
08:26It orbits around its star at lightning speed,
08:30completing a revolution in just 21 hours.
08:33It is the planet known for its densest ultra-short revolution period,
08:37with well-measured properties.
08:39Its neighbor, K2-360c,
08:42is a much more massive planet,
08:44with at least 15 Earth masses.
08:46It takes 9.8 days to orbit,
08:48but as it does not pass in front of its star from our point of view,
08:51its exact size remains unknown.
08:55This exceptionally dense planet
08:57could be the residual core of a much larger star.
09:01The intense radiation of its star
09:03could have, over time,
09:05blown its external layers,
09:07leaving only a rocky core.
09:09It could thus offer a glimpse of the fate of planets
09:12too close to their star.
09:14Astronomers estimate that K2-360b
09:16could have migrated inland
09:18as a result of gravitational interactions
09:20with its more massive companion.
09:22One of the hypotheses is based on a high eccentricity migration,
09:26where the initially stretched orbit of the planet
09:29gradually stabilizes,
09:31making it more circular near the star.
09:33Another theory suggests that the rotation
09:35and axial inclination of the planet
09:37could play a role in this phenomenon.
09:39Planets of this type are rare,
09:41and discovering a combination of a giant companion
09:44would allow to refine the models of scientists
09:46on the formation and planetary evolution
09:49in extreme environments.
09:51This discovery could also enlighten
09:53the future of rocky planets,
09:55in particular those that are too close to their stars.