00:00It could well be that we have fallen into the sea of all water reserves, and it floats in space.
00:07It has been hiding under our nose for at least 12 billion years.
00:11As for its size, it is difficult to imagine.
00:15140,000 billion times larger than all the oceans of our planet combined.
00:21This cosmic aquatic world is orbiting a large black hole called Quasar,
00:28located 12 billion light years away.
00:30Quasars are supermassive black holes that emit colossal amounts of radiation.
00:36It is estimated that this one is 20 billion times heavier than our sun,
00:40and that it carries an energy capable of illuminating 1,000 billion.
00:45In our Milky Way, we are used to seeing water in the form of ice.
00:50The water reserve we are talking about here seems to be in the form of steam.
00:54The important thing in this discovery is that there could be water everywhere in the universe.
00:59All you have to do is know where to look.
01:02You may be surprised to learn that all the stars are not hot to the touch.
01:06Until now, we believed that all the stars were as bright as our sun,
01:11fireballs ready to melt everything in their path.
01:15But there are colder ones, the brown dwarfs.
01:18Their particularity lies in the fact that they are too small to carry out the nuclear fusion
01:23that allows the stars, like our sun, to shine.
01:26They do not emit much light or heat, which makes them difficult to see.
01:31These brown dwarfs are divided into different categories.
01:34The coldest Hygia-type stars have a surface temperature lower than that of a cup of tea.
01:40If you could touch one, you would only feel a soft heat.
01:45About 4 billion years ago, Uranus apparently exchanged its place with Neptune.
01:51It is difficult to imagine that such large planets could do that.
01:55But this theory could solve the mystery of the formation of our solar system.
02:00We know that rocky planets formed as a result of major collisions.
02:04Take our planet, for example.
02:06About 4 to 6 billion years ago, things were quite shocked around the sun
02:11until the Earth reached its final form.
02:14During this period, a larger collision made enough rocks and gases explode
02:20to give birth to the Moon.
02:22But as for our neighbors in the solar system, Jupiter, Uranus and Neptune,
02:27scientists still have no answer.
02:30According to standard models, it would take an eternity for them to form.
02:34It would exceed the age of the solar system itself.
02:37If this new theory is correct,
02:39then Uranus and Neptune would be born from a dense gas cloud compacted around the sun.
02:44The problem is that for this theory to stand,
02:48these planets must have exchanged their places at some point in history.
02:52Neptune is about 4.5 billion kilometers away,
02:57the largest distance a planet can reach in our solar system.
03:01Uranus is a little closer, at 3 billion kilometers.
03:05This new idea suggests that after their formation,
03:07much closer to the sun than they are today,
03:10their positions have been modified.
03:12This could be due to the passage of many comets for billions of years
03:16that would have slowly moved these giant planets away.
03:19This is not a definitive answer to the question of how they formed.
03:24It is rather a strong intuition supported by many data.
03:28Speaking of strange things found in our universe,
03:32what about this floating spoon that NASA's Curiosity rover photographed on Mars
03:38while the rover was walking on the red planet?
03:41It fell on this strange spoon-shaped rock in the summer of 2015.
03:46The rock has a handle and even projects a shadow on the ground.
03:50It is not an abandoned utensil during a Martian picnic,
03:54but what NASA scientists call a ventifact,
03:58a rock carved by the wind.
04:00This is not the first time that the Martian surface has delighted us with strange wind sculptures.
04:05There was the face on Mars, a rat, and even beignets with jam.
04:12It is possible that diamonds rain on more than 1900 exoplanets.
04:17Scientists have discovered that it is not necessary to have particularly high temperatures
04:22for carbon to turn into diamonds, as it was believed before.
04:27Until recently, we only knew Neptune and Uranus as likely to present such rain.
04:33Astronomers have been interested in this phenomenon for about forty years.
04:38But these planets were difficult to study.
04:41Only the Voyager 2 probe was able to take a look.
04:45However, considerable progress has been made thanks to laboratory simulations.
04:52Neptune and Uranus are ice giants,
04:55because their outer layers are filled with hydrogen, helium, water and ammonia,
05:00what scientists call ice.
05:03Their magnificent blue hue is due to the methane present in their atmosphere.
05:09But diamond rains occur lower, in the depths.
05:13If we could visit them, we would see that under the thick atmosphere,
05:17there are very dense layers of ice.
05:20All this pressure leads to chemical reactions
05:23that can generate diamonds the size of a small city.
05:28We cannot plunge into Neptune or Uranus with a probe looking for diamonds.
05:33Instead, we reproduce these conditions in laboratories
05:37by pressing the matter between diamond clusters
05:40and hitting it with lasers to imitate the extreme environment of these planets.
05:45Thanks to this, scientists have managed to create artificial diamonds.
05:50Understanding how these rocks are formed there
05:53could also explain why Neptune is warmer than it should be,
05:57and why it knows such intense storms.
06:00These diamonds could also allow us to pierce the mystery
06:03of the strange magnetic fields of Uranus and Neptune.
06:07If we compare what is happening on our planet,
06:10we find very different results.
06:12So there may be strange things going on with the magnetism of these planets.
06:16NASA plans to send a new probe to Neptune or Uranus in the next decade.
06:22As the planets will align perfectly in 2030,
06:25the time will be ideal to explore these sparkling worlds up close.
06:32Planet Kepler-78b is another strange cosmic discovery.
06:37This hot world, in fusion,
06:39goes around its star in record time, once every eight and a half hours.
06:44It is only 1.6 million kilometers away.
06:49If we could put our foot on its surface,
06:52we would notice that its sun is 80 times larger
06:55than the star we see every day in our sky.
06:59If we apply what we know so far about the formation of the planets,
07:03this little guy should not even be there.
07:06Specialists still have no idea how it appeared
07:10or where it is.
07:12What we know is that it will soon disappear, in a way.
07:17As it is extremely close to its sun,
07:20this burning planet will collide with it in a few billion years.
07:25It's relatively short on the cosmic level.
07:29What is similar between our planet and Kepler-78b is density.
07:34Of course, it is about 20% larger than Earth
07:38and weighs almost twice as much,
07:40but it has the same solid interior.
07:42It is impossible for it to form closer to its star
07:45and for it to simply move away over time.
07:48It cannot be born much further away and have migrated inwards.
07:52Any movement inwards would have been impossible to stop.
07:56And it would have collided with the star.
07:59This discovery may not be particularly revolutionary,
08:02but there is a good chance that you never thought about it.
08:05There may be space dust in your hair right now.
08:09Every day, piles of materials from space come crashing down on Earth.
08:13Sometimes, these objects are visible,
08:16like when a meteor turns into a meteorite by crashing on the ground.
08:21But most of the time, it's more discreet.
08:23These materials drift through the atmosphere and land
08:26in the form of what we call space dust.
08:29It may not be much,
08:31but it is about 14 tons per day.
08:34This dust contains tiny fragments of rocks and metals
08:37detached from asteroids and comets during major collisions.
08:41These particles are very small.
08:43You wouldn't be able to see them without sophisticated instruments.
08:46But every time you leave your home,
08:48a part of these particles may land in your hair.
08:53NASA Jet Propulsion Laboratory, California Institute of Technology
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