Saviez-vous que les pôles terrestres pourraient un jour s'inverser, faisant pointer les boussoles vers le sud au lieu du nord ? Les scientifiques ont découvert que cette inversion des pôles est une partie naturelle du cycle magnétique de notre planète, qui s'est produite de nombreuses fois au cours de millions d'années. Lorsque ce changement magnétique se produira, il modifiera considérablement notre façon de naviguer et pourrait même affecter notre technologie. Un autre fait fascinant est que les jours pourraient devenir plus longs, s'étirant éventuellement jusqu'à 25 heures au lieu du cycle habituel de 24 heures auquel nous sommes habitués. Ainsi, à l'avenir, nous pourrions réellement avoir un peu plus de temps pour nous détendre et profiter de chaque jour ! Animation créée par Sympa.
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Musique par Epidemic Sound https://www.epidemicsound.com
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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
00:00Solar eclipses are amazing.
00:03The Moon and the Sun seem to overlap perfectly in our sky,
00:06while in reality, the Sun is much larger, about 400 times.
00:11The thing is that the Moon is also about 400 times closer to our planet,
00:16so that we have the impression that they are the same size.
00:20Unfortunately, at some point in the history of our planet,
00:24there will be no more solar eclipses.
00:26Indeed, the Moon moves away from the Earth by about 4 cm per year.
00:32Because of this phenomenon, the Moon will no longer completely hide the Sun.
00:37NASA experts have calculated the date of the last solar eclipse.
00:42According to them, it will still have to wait about 600 million years.
00:46So we can say without the risk of being wrong,
00:48that none of us will be there to see it.
00:51Speaking of things that we will not see from our living,
00:54it may be necessary to add the explosion of stars.
00:57Thanks to telescopes, we know what stars look like when they go out,
01:01but we have never witnessed this phenomenon with our own eyes.
01:06Betelgeuse may not be a familiar name to you.
01:09It is a super red giant, located about 1000 light-years from Earth.
01:15What it has in particular is that it could explode
01:18and offer us an unprecedented spectacle seen from here on Earth.
01:22The date of the explosion of this star has always been a bit mysterious.
01:27What we know is that Betelgeuse is in the last stages of carbon combustion of its core.
01:32And this phase of carbon combustion usually lasts a thousand years.
01:37As a result, we will not see stars collapse immediately.
01:41But as this event will most likely be harmless for our planet,
01:45it will be highly anticipated by future generations.
01:49If you want to see Betelgeuse in the night sky,
01:52know that it is generally visible in January and February,
01:55and that at the beginning of August, it is visible before sunrise.
02:00Its attenuated red-orange hue is unique
02:03and proves to us that the stars do have colors.
02:07Our planet will also undergo many changes in the future.
02:10If we could travel a few million years into the future,
02:13it may well be that we no longer recognize the geography of our pretty globe.
02:18Currently, the Earth has seven continents, but it has not always been so.
02:22And it is very likely that this will change again in the future.
02:25About 310 million years ago, the Earth had a megacontinent called the Pangaea.
02:31About 180 million years ago, it began to disintegrate.
02:35Today, scientists think that in the next 200 million years,
02:39we could witness the formation of another great continent.
02:43In fact, it could be in the process of forming right now.
02:47And there are four main scenarios on how this could happen,
02:52each with its own particularities.
02:54They all bring us back to the division of the Pangaea
02:57and to the way our continents continue to move.
03:00Our day, the 24-hour cycle in which we live, also stretches slowly.
03:06This progressive change will ultimately lead us to 25-hour days.
03:10And this is why the rotation of the Earth,
03:14this movement that we make every day, slows down a little more every year,
03:18and this thanks to the Moon.
03:20Indeed, our satellite flies us to incite a part of our terrestrial energy.
03:26We are aware of this phenomenon thanks to the Laser Ranging Retroreflector.
03:31It sends laser beams to the Moon,
03:34and after bouncing, it takes a little more time to return to Earth.
03:39This little delay is an indication that our days are stretching.
03:43So, how long will it take before we have one more hour to finish our daily chores?
03:50NASA experts have made some calculations.
03:53Over the last century, our days have extended by about 1.4 milliseconds.
03:58If we zoom back and examine the last two millennia,
04:02based on historical data from solar eclipses,
04:06our days have extended by an average of 2.5 milliseconds per century.
04:12I spare you the calculation.
04:14It will take about 50,000 years for a single second to add up to our day.
04:19This means that it will take 180 million years for a day on Earth to count 25 hours.
04:25And this, of course, if nothing else happens in the meantime at the level of the rotation of our planet.
04:32The Milky Way is one of its closest neighbors.
04:35It is also expected to merge one day or the other.
04:38We will not be there to witness this meeting,
04:41but we will not see any major changes at Earth level anyway.
04:45The collision of galaxies may seem a little unusual,
04:48especially since we know that the universe is expanding.
04:52If galaxies are moving away from each other more and more,
04:55how can they still meet?
04:58Close galaxies do not just float.
05:01They each have an effect on the other, thanks to gravity.
05:04This is the reason why the Milky Way and Andromeda
05:07are approaching at a speed of about 300 km per second.
05:11If we do the math,
05:13this means that their collision will not occur before 4 or 5 billion years.
05:18And there is a good chance that they will meet gently,
05:21without any notable change within our solar system.
05:26In the distant future,
05:28the amazing ice rings of Saturn will no longer be there either.
05:33At least, according to recent research.
05:37NASA's Cassini mission,
05:39which spent time orbiting Saturn between 2004 and 2017,
05:42has collected new information on these rings
05:45and on the date of their disappearance.
05:48Scientists have long debated the age of Saturn's rings.
05:53Some thought they were relatively young,
05:56their ice still being fresh and bright.
05:59Over billions of years,
06:01the rings would be worn out and darkened
06:03due to the various objects that came to intermingle with them.
06:06But these rings were perhaps still at an embryonic stage
06:09at the time when dinosaurs inhabited the Earth.
06:12When foreign bodies filter between the rings,
06:15they push some of the innermost circle matter towards the planet
06:18at a fairly fast rate.
06:21Cassini thus found that the rings were losing a lot of mass every second.
06:25This means that they will no longer be visible for a very long time.
06:28In cosmic terms, at least.
06:30It is estimated that they will only last a few hundred million years at most.
06:35We could also miss this next cosmic event,
06:38but very little.
06:40Indeed, according to some estimates,
06:42it could only happen in a hundred years.
06:46The Earth's magnetic field could collapse
06:49and reverse the North and South Poles.
06:51Researchers have stated that for 3,000 years,
06:54our planet's magnetic field has been constantly declining.
06:58If this trend continues,
07:00we could reach a critical point in less than a millennium.
07:04For the planet's poles to tilt,
07:06the magnetic field must weaken by about 90%,
07:09which can take thousands of years.
07:12During this phase of vulnerability,
07:14our planet loses its protective shield
07:16and lets more rays pass from space.
07:21The last time such an inversion of the poles occurred
07:24was nearly 800,000 years ago.
07:26The problem is that we are currently in one of the most risky phases.
07:30The magnetic field is weakening,
07:32but it is possible that it will regain vigor.
07:35However, at this rate,
07:37it could brutally fall within a few centuries or a millennium.
07:41We can already see the effects of the weakening of the magnetic field on our satellites.
07:46In the vast expanse of the Atlantic Ocean,
07:49between South America and Africa,
07:51there is a region where the Earth's magnetic field
07:53is three times weaker than the poles.
07:55Scientists call this the South Atlantic Anomaly.
07:59The satellites that cross this zone
08:01regularly experience electronic problems.
08:04No one knows why the magnetic field is so weak in this region,
08:08and no one knows what will happen to it in the future.
08:11According to a theory,
08:13a massive whirlwind in the outer metallic core of the Earth
08:16could be responsible for it.
08:18It would push the magnetic field away from the South Atlantic.
08:21Another idea is that this field, in this region,
08:24is pointing in the wrong direction,
08:26like a spinning mini-pole.