00:00A recent study has implicated almost 200 giant stars who arrive at the end of their lives.
00:07It has given to scientists more precise information on how the Sun will end up one day.
00:13It is apparent that the Sun will be about 200 to 300 times bigger than it will be now when
00:17its end will arrive.
00:21To start, let's talk about some basic information on the size of the stars.
00:25The big stars atteign this stage because they have exhausted their nuclear carburant and they don't burn anymore hydrogen in
00:31their noyau.
00:32Finally, the noyau becomes enough hot to cause the next step of fusion, which is the combustion of the helium.
00:39All the stars examined in this new study were either in this phase of combustion of the hydrogen in the
00:45envelope,
00:45or in the phase of combustion of the helium in the noyau.
00:49Even if the giant stars and super giant stars represent less than 5% of all the stars, at least
00:54those that we know,
00:56they are actually very visible from far away because they are very luminous.
01:01In fact, according to scientists, about a third of all the stars that you can see outside by a night
01:07sombre without Lune
01:08are giant stars or super giant stars.
01:11This study will be provided to the astronomers really useful information on the massive stars.
01:17They will determine their size and temperature, regardless of where they are or their state of evolution.
01:23This means that they can see the true color of a star and use it to discover their rayon.
01:30Pretty cool, non ?
01:33What does our solar star look like when it becomes vieux and grincheux?
01:37In simple terms, it will expand when it begins to burn its hydrogen hydrogen,
01:41but increases a little during its phase of combustion of the helium.
01:46After hundreds of millions of years, it will end up becoming a giant star
01:50about two to three hundred times its current size.
01:54Finally, the solar star will expand so much that it will end up simply by evaporating.
01:59Ainsi, what will happen when the solar star will turn up?
02:03In fact, scientists have some predictions about what will happen, even if we will not be there to see it.
02:10They are almost sure that the solar star will turn up into a solar star.
02:14These solar star are fragments of gas and dust in the space from a star from a star that s
02:20'éteint.
02:21They received their names because they looked at planets for people using telescopes at the 18th century.
02:27Even if we now know that they have nothing to do with the real planets.
02:32But here is what is extraordinary.
02:35The astronauts have discovered that they can use the level of luminosity of these planets
02:39to calculate their distance compared to us.
02:43In 2018, scientists have also discovered that the solar star is the smallest star
02:48that could still produce a visible solar star.
02:51Plus small, they would not be visible.
02:54The solar star, which have up to three times the mass of the solar star, will produce a brighter
02:58solar star.
03:01The solar star is currently 4,6 billion years old, but it is estimated that it is still
03:0610 billion years old before its end.
03:09The solar star will also become more luminous every year.
03:13It is not a lot for now, but it will actually cause big problems for the Earth.
03:19In about 1 billion years, the solar star will be too bright for the life on Earth to survive.
03:25Our oceans will evaporate and it will be too hot for the air to be reformed.
03:30So, to not find a way to quit this planet, humanity has about 1 billion years before it.
03:37The Earth will still exist again when the solar star will transform the solar star?
03:42It is difficult to know with certainty the exact same thing.
03:45But even before it is happening, the Earth will be very likely to be calcined and without
03:50life, without atmosphere or ocean.
03:53We don't know precisely how far the outer layers of the solar star will approach the
03:57Earth.
03:57But if they approach too much, it could lead to the Earth to spiral the Earth and disappear completely.
04:05Even if our planet comes from one way or another to survive at the giant phase of the
04:09solar star, it will orbit around a white white star, that is to say, a star that has
04:15exhausted its carbonated.
04:16In this distant future, the solar star will be just as big as our planet.
04:21Finally, the solar star will be cold and completely assombring it.
04:24It will enter into another phase called a black star.
04:28This will destroy the Earth orbit and our planet will spiral towards the solar star.
04:33But it is interesting to note that the solar star does not have the last word on what
04:37happens to the Earth.
04:38The gravity maintains the planets in orbit, but it also attracts them to the other ones,
04:43which can cause a flexion and a derive of their orbits.
04:47This could lead to the destruction of the solar system and ejection of planets, including
04:52the Earth.
04:53In general, many things could happen in the 5 billion years to come before the solar star
04:58become a blue star.
05:00There is also another scenario.
05:03Even that most of the stars are far away from our solar system, there is a chance that one
05:07of them could approach the next billion years.
05:11Even a small star or a black star could perturb the orbit of our planet if they
05:15are too close.
05:16But don't worry too much, the chances that this happens are weak because of the distance between the stars.
05:24Our solar star is a solitary star, so there is a little chance that we can climb to
05:29the board of another star to close.
05:31However, many stars in our universe have companions.
05:35Among these stars is Castor, a beautiful system that includes six stars and is one of the
05:42most luminous objects of the dark ciel.
05:50Even with the help of a small telescope, it is evident that Castor is composed of two
05:59main stars, Castor AA and BA, which gravitent the one around the other.
06:04These stars are bigger than the Sun and need 467 years to complete an orbit.
06:11In total, Castor is composed of six different stars.
06:16The largest, called Castor AA, is about two times bigger than the Sun, while the smallest
06:22has about 0,5 the mass of the Sun.
06:26If humans want to survive in the next billion years, we should maybe establish a
06:31campement in the universe.
06:32This may seem right out of a science fiction film, but it could become our reality one day.
06:38Unfortunately, NASA already examine some options.
06:42They have discovered two new planets.
06:45Toi-700E and Toi-700D, which could be the new points for us, humans.
06:53Toi-700E is in the zone optimist, which means it could have an air and even an atmosphere.
07:00Toi-700D is in the zone habitable conservatrice.
07:03So, scientists are not yet certain to this subject.
07:06But well, we take what we can obtain.
07:10But wait.
07:11Before starting to prepare your bags, there is a little problem.
07:15How are we going to do it?
07:16We need to prepare for John Glenn just to do three times the tour of the Earth.
07:21So, we should maybe start working on our training of astronauts.
07:25Eh bien, au moins, nous avons quelques options pour nos futurs projets de vacances intergalactiques.
07:32Ne serait-il pas agréable de pouvoir voyager dans le temps pour voir à quoi ressemblera notre système solaire dans
07:37des milliards d'années ?
07:38Un physicien américain nommé Ron Mallette a proposé une théorie intéressante pour le voyage dans le temps.
07:44Elle utilise la lumière, une ressource abondante dans l'univers.
07:48Son idée implique l'utilisation d'un cylindre rotatif de lumière, qui pourrait transporter un objet à la fois dans
07:53l'espace et dans le temps,
07:55de manière similaire à la façon dont une bulle se déplace dans un liquide en mouvement.
07:59Mallette suggère qu'un cylindre de la bonne forme pourrait permettre de voyager dans le passé et le futur.
08:04Pour tester sa théorie, il a tenté d'obtenir des financements pour une expérience.
08:10Cependant, certains scientifiques considèrent que la théorie de Mallette est impossible et inutile à tester.
08:16Nous pourrions également être capables de voyager dans le temps si nous nous déplaçons suffisamment vite.
08:22Selon Einstein, la façon dont nous vivons le temps peut changer en fonction de notre vitesse de déplacement.
08:27Si nous allons vraiment vite, le temps ralentit.
08:30Par exemple, les astronautes dans l'espace vieillissent un peu plus lentement que les gens sur Terre.
08:36C'est important pour des choses comme le GPS, qui serait incorrect sans ajustements spéciaux, à cause de comment le
08:42temps est affecté.
08:43Sous-titrage Société Radio-Canada
08:47Sous-titrage Société Radio-Canada
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