00:00Scientists have discovered an invisible star nestled in the heart of the Milky Way,
00:05a star that played a key role in the birth of our galaxy.
00:09Situated 26,000 light years away, in its center,
00:12a massive and imperceptible object began to spread everywhere
00:16and wanted to invade it at every moment without even realizing it.
00:19It all began in the 1970s,
00:21when an astronomer named Vera Rubin started studying the galaxy of Andromeda.
00:26Her goal was to check if the stars were following predictable trajectories.
00:31Imagine that you were spinning a ball at the end of a string around you.
00:35The closer it is, the faster it turns on a reduced orbit.
00:39Conversely, if you release the string, the ball slows down and describes a wider circle.
00:45This is the fundamental principle of gravity.
00:47It is the same for planets.
00:49Those that gravitate near the sun, like Mercury,
00:52travel in their orbit in just a few months,
00:55while those furthest away, like Neptune and Saturn,
00:58take several decades to complete their evolution.
01:01The stars should therefore follow this same pattern by orbiting around the center of their galaxy.
01:06The closest ones move quickly, while those located on the periphery should slow down.
01:12However, when Rubin measured their speed, she made a disturbing discovery.
01:16These stars did not slow down.
01:19Distant stars were moving at a speed comparable to those near the center.
01:23Logically, these galaxies should have dislocated.
01:26Yet, they remained intact.
01:28This paradox indicated that a mysterious force kept them in cohesion.
01:33An undetectable presence, a massive and invisible object hidden in the galactic center,
01:38exerting its influence without ever revealing itself.
01:41Rubin began to repeat these observations on other galaxies.
01:44It was not an isolated anomaly, but an omnipresent phenomenon.
01:48It happened by chance to highlight that these cosmic structures
01:52were bathed in a matter of colossal density,
01:55much higher than that of all the stars, planets and gas clouds combined.
01:59An invisible force enveloped them.
02:02Astronomers called this entity black matter,
02:05because it does not emit any light, does not reflect it,
02:08and does not seem to interact with any other substance.
02:11It is simply there.
02:13And yet, all models confirm not only its existence,
02:17but also its fundamental role.
02:19It alone constitutes 85% of the total mass of the universe.
02:24Without it, the world as we know it would not exist.
02:28Yet, just like the invisible star detected in the center of the Milky Way,
02:32the only way to perceive it was its gravitational footprint.
02:36How to uncover what refuses to be found?
02:40Recently, scientists have hypothesized the existence of an invisible star
02:45in the center of the Milky Way.
02:47A fascinating discovery that could finally give us a glimpse
02:50of the real nature of black matter.
02:52They started by tracking the slightest clues of its existence,
02:56scrutinizing all possible signs of its presence.
02:59They analyzed the movement of galaxies
03:01and caused collisions of particles in giant accelerators,
03:05hoping to generate tiny fragments of black matter in the laboratory.
03:09But these efforts did not yield results.
03:12They even ignored what they were looking for.
03:15Is black matter only made up of particles?
03:18A theory suggested that it would be made up of ghostly particles,
03:22barely able to interact with ordinary matter.
03:25Other hypotheses suggested that it could appear and disappear in a blink of an eye.
03:29A problem still existed.
03:31If black matter worked that way,
03:34then the galactic centers should be incredibly dense,
03:37saturated with compressed matter in a tiny volume.
03:40However, the observation reveals a completely different reality.
03:43The cores of galaxies seem surprisingly diffuse,
03:46extended, almost ethereal.
03:48It is then that a new theory has emerged.
03:51What if the black matter nested at the heart of galaxies
03:54was not made up of heavy particles as we had long assumed?
03:57What if it was of such a thin nature
04:00that it behaved more like an air filament?
04:03These hypothetical filaments would be of incredible lightness,
04:06far beyond all that science has been able to observe so far.
04:09They would even be billions of times smaller than a neutrino,
04:12yet already the lightest known particle.
04:15This concept, called blurry black matter,
04:18could upset everything we thought we knew about the universe.
04:21A team of astrophysicists wanted to test this hypothesis.
04:25They therefore designed a simulation,
04:27modeling a galaxy with two main elements,
04:30a large amount of blurry black matter and a small fraction of gas.
04:34The same type of gas that generates the visible stars.
04:37Once the program was launched,
04:39they simply let the system evolve,
04:42carefully observing the interaction between these two components.
04:45At first, it was a total chaos.
04:48But gradually, the blurry black matter began to condense,
04:52grouping together to form a gigantic invisible object
04:55near the galactic center.
04:57The gas reacted immediately,
04:59dispersing in this impalpable mass,
05:02mixing and generating a faint glow.
05:05Then, an extraordinary phenomenon occurred,
05:08giving birth to dark stars.
05:10Unlike classic stars like our sun,
05:13radiating heat and light,
05:15these objects were colossal, invisible,
05:18and resulted from the fusion of two forms of matter.
05:21A totally new entity, never observed before.
05:24These structures extend over thousands of light years,
05:28while being almost immaterial,
05:30closer to huge cosmic clouds than to real stars.
05:33Their nature, their value,
05:35to be named boson-fermion stars.
05:38Finally, the mystery of black matter seemed to find an explanation.
05:42The nucleus of these invisible stars
05:44presented an ideal density,
05:46neither too high nor too low,
05:49and corresponded exactly to the observations of astronomers
05:52on real galaxies.
05:54If this hypothesis had just been confirmed,
05:57it could explain the behavior and role of black matter in the universe.
06:01Each galaxy in the universe could then be influenced
06:04by one of these gigantic ghost objects.
06:06The star hidden in the heart of the Milky Way could be one,
06:09shaping our galaxy in a way
06:11we had never been aware of.
06:14This matter would behave very differently from ordinary matter.
06:17Unable to form solid structures,
06:19it would exist in the form of a complex network
06:22moving filaments or hair.
06:24This also means that the Earth could be completely plunged into it.
06:27The black matter being subjected to gravity,
06:30it is attracted by planets and stars,
06:33concentrating in dense flows
06:35that lead it to cross our planet,
06:37while constantly oscillating.
06:39If we could observe it,
06:41it would appear in the form of luminous and invisible filaments,
06:44piercing the planet and stretching into space.
06:47But this is just the beginning.
06:49Now, scientists must refine their models,
06:52enrich them with details,
06:54and confront their predictions with real observations of galaxies.
06:57The discovery of a dark star in the heart of the galaxy
07:00is not our only clue.
07:02Fortunately, a cosmic phenomenon
07:04allows us to detect the trace of it.
07:06The gravitational lens.
07:08When the light of a distant galaxy crosses the universe,
07:11it can cross a massive galaxy
07:13or another object with an intense gravitational field.
07:16Rather than continuing its trajectory in a straight line,
07:19it is then curved by this colossal force.
07:22Reaching Earth, this distorted light
07:24offers a enlarged and distorted image of the original galaxy,
07:27as if we were looking through a curved glass.
07:30If the black matter is blurry,
07:32it should leave a singular imprint on these images,
07:35making some areas slightly troubled and wavy.
07:38To have confirmation of this,
07:40an ideal object had to be observed,
07:42and scientists have found one.
07:44A distant galaxy whose light,
07:46deformed by gravity,
07:48presented a strange elongated silhouette.
07:51They then connected radiotelescopes from all over the world,
07:54forming a virtual planetary-scale telescope.
07:57It was able to zoom in
07:59to perceive the smallest details of this galaxy
08:02as clearly as a grain of sand on the Moon.
08:05They then conducted a vast experiment
08:07generating simulations of this image
08:09with different sizes of blurry black matter particles.
08:12At a precise moment,
08:14they ended up discovering a perfect correspondence.
08:17This allowed them to calculate the exact mass of these particles
08:20well before detecting them.
08:22The clues point directly to our own galaxy.
08:25The densest areas of these cosmic hairs,
08:28their roots,
08:30could be surprisingly close
08:32to only a few tens of thousands of kilometers from Earth,
08:35a distance accessible for a space probe.
08:38With the discovery of this invisible star
08:41in the center of the Milky Way,
08:43it remains only to study it closely.
08:45A mission to one of its roots
08:47could finally allow us to solve
08:49one of the greatest mysteries of the Universe.
Comments