00:00At lightning speed, this mysterious object crosses our galaxy at nearly 1.6 million kilometers per hour.
00:08Its speed is such that it could even escape the gravitational grip of the Milky Way.
00:13While scientists are trying to elucidate the exact nature of this cosmic curiosity,
00:18let's launch into space to better understand the mysteries.
00:22The object in question, CWIS-J1249, is currently evolving at a distance of 400 light-years from Earth.
00:30Let's take a closer look to determine whether it could be a wandering probe.
00:35This seems unlikely due to its impressive size.
00:38It is 30,000 times more massive than Earth and represents 8% of the mass of the Sun.
00:44Such a mass ranks it in a category that Dr. Darren Baskill,
00:48a professor of astronomy at the University of Sussex, describes as
00:52« located between a star and a planet ».
00:55Stars capable of reaching such phenomenal speeds are extremely rare.
01:00Only one or two stars out of a thousand in our galactic neighborhood reach such a speed.
01:07If you were to one day observe one moving as fast as this cosmic enigma,
01:12you would see it leave the Milky Way in just a few tens of millions of years.
01:16A nod in terms of cosmic time.
01:18Let us remember that such stars can survive for tens of billions of years.
01:23Although the mysterious CWIS-J1249 only travels at 0.001% of the speed of light,
01:30its velocity remains high enough to potentially escape the gravitational attraction of our galaxy
01:36and fly into intergalactic space.
01:39To better grasp the extent of its speed,
01:41know that J1249 exceeds 2.6 times that of the fastest ever launched space probe,
01:48the Parker Solar Probe,
01:50which reached its peak in June 2024 by orbiting around the Sun.
01:55J1249 was discovered by volunteers of the Backyard Worlds project, NASA's new planet.
02:03These researchers analyze the images reported by the Wide Field Infrared Explorer and NeoWISE missions,
02:09scrutinizing all signs worthy of interest.
02:12Three of them spotted a fast and diffuse point crossing the images of WISE.
02:18When they understood the nature of their discovery, they were overwhelmed with enthusiasm,
02:23although they first thought that this space object had already been reported.
02:27However, to their great surprise, this was not the case.
02:31Currently, most scientists estimate that CWIS-J1249
02:37could be either a low-mass star or a brown dwarf.
02:41However, this type of star, larger than a planet,
02:44does not have the size necessary to maintain a nuclear fusion in its core,
02:48as our Sun does.
02:50In other words, these stars do not have enough mass
02:54for their nucleus to burn its stellar fuel and radiate.
02:57This is why brown dwarfs, often referred to as failed stars,
03:02are smaller and colder than the Sun.
03:05They even have complex atmospheres, similar to those of planets,
03:10including clouds and molecules such as water.
03:14In order to verify this hypothesis,
03:17astronomers continued their observations using terrestrial telescopes.
03:22They quickly detected an unusual chemical composition for the object,
03:26displaying iron levels and other metals much lower than those of stars
03:30or ordinary brown dwarfs.
03:32This led NASA to issue a bold hypothesis.
03:36J1249 could be one of the oldest stars ever identified in our galaxy.
03:44This upheaval raises a question.
03:46Why is this hypothetical star moving so fast?
03:50Researchers are considering several scenarios.
03:53One of them assumes that it is a remnant of a binary stellar system,
03:57in which one of the members, a white dwarf,
04:00would have exploded as a supernova after absorbing too much matter from J1249.
04:06Another hypothesis suggests that the star could come from a stellar mass
04:11that would have dislocated after meeting two black holes.
04:15According to the specialists, one way to reach such a velocity
04:19is to move towards a massive object without reaching it,
04:23which produces a gravitational wave effect.
04:26This phenomenon is used to accelerate space probes,
04:30allowing them to explore the solar system in a reasonable time scale.
04:34The speed of J1249 could be explained by a similar mechanism.
04:39The star could have been born in the overpopulated core of the galaxy,
04:43move towards another star without hitting it,
04:46and thus gain an extreme speed.
04:49Let's now let the astronomers continue their investigations
04:52to confirm this fascinating hypothesis.
04:55Meanwhile, let's go to the binary system 55 Cancri,
04:59located 41 light-years from Earth.
05:02This system houses an amazing planet.
05:0555 Cancri E, alias Jonsen.
05:10This super-Earth, 8 times more massive than our planet,
05:14orbits around its star in a little more than 17 hours,
05:17a much shorter year than a terrestrial day.
05:20In addition, the planet is 25 times closer to its star than Mercury is to the Sun,
05:26which explains why its surface reaches an infernal temperature of 2400°C.
05:32It's hot enough to melt most of the known metals.
05:36In 2010, researchers discovered that the high star of 55 Cancri
05:41had a particularly high carbon-oxygen ratio.
05:45If this same ratio also applied to the planet,
05:48it could receive immense amounts of carbon,
05:51and the most incredible.
05:53This carbon could exist in the form of diamonds.
05:56This would make 55 Cancri a real planet of jewels.
06:02Unfortunately, later studies revealed that this carbon-oxygen ratio
06:07was less extreme than initially thought,
06:10making the existence of a gem-encrusted world unlikely.
06:14However, the composition of the planets does not always reflect
06:17exactly that of their high star.
06:19If an external process had enriched the amount of carbon in 55 Cancri E,
06:24it could still remain the most precious planet in the universe.
06:28It would certainly be worth the detour.
06:30But let's leave behind us this diamond planet to go to Vega,
06:34one of the brightest and most important stars in the night sky.
06:38The brightness of the other stars is evaluated compared to Vega's,
06:43on a scale where its own magnitude is zero.
06:46A magnitude star is 1.25 times less luminous than Vega,
06:51while a magnitude star is 1.25 times brighter.
06:56Vega was also a polar star, although it is no longer the case.
07:00Today, the axis of the Earth points to Polaris, the North Star.
07:05However, the axial inclination of the Earth draws a circle
07:08over a period of about 26,000 years,
07:10and Vega will become the polar star again in about 12,000 years.
07:14Patience.
07:15What really distinguishes Vega from the other stars
07:18is that it does not have a perfect spherical shape.
07:21Unlike the Sun, which rotates slowly and is practically spherical,
07:25Vega makes a complete rotation in just 12 hours and a half.
07:29This rapid rotation causes an equatorial inflation,
07:32giving it an ovoid appearance.
07:34And now, prepare for the most dangerous meeting of all.
07:38But before that, a warning is necessary.
07:41Although space is of inconceivable immensity,
07:44it is extremely sparsely populated.
07:47The average density of the universe is equivalent to 6 protons in a volume of 1 m3.
07:52Some regions, called empty or super-empty,
07:55contain even less matter.
07:57These areas are colossal.
07:59They can extend over 30 to 300 million light years,
08:03and almost nothing can be found.
08:05We also find in the universe places where time and space are deformed
08:09in order to challenge any human understanding.
08:12Like the binary black holes systems,
08:14where two massive black holes gravitate around each other
08:18before finally merging.
08:20As they approach in a spiral,
08:22they emit powerful gravitational waves
08:25that propagate through space-time.
08:28The first detection of these waves was made in 2015
08:31by the Laser Interferometer Gravitational Wave Observatory, LIGO,
08:36when it recorded the final collision of a pair of black holes.
08:40During the 20 milliseconds preceding the fusion,
08:43these black holes released more gravitational energy
08:46than the total energy emitted by all the stars of the observable universe
08:50during the same period.
08:52But the universe has much more to offer.
08:54By exploring more,
08:56you could come across exoplanets like Corot T7b,
08:59where rock clouds form and pour down stone wells,
09:03or KILT 9b, the hottest known planet,
09:08with surface temperatures reaching 4,300 °C,
09:12or TRES-2b,
09:15the darkest planet ever discovered.
09:18It absorbs more than 99% of the light it receives,
09:22making it darker than coal.
09:25Thus, on a vast and almost unfathomable scale of the cosmos,
09:29fast and mysterious objects,
09:31strange planets and immense voids
09:34remind us how much there is still to discover in the universe.
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