00:00 The sun is about to turn around because its magnetic poles are inverting.
00:04 Just like the Earth, the sun has a magnetic north and a magnetic south.
00:08 However, unlike our planet, the process of inversion of the poles of the sun is more frequent and easier to predict.
00:15 The next reversal is scheduled for this year between April and August.
00:19 As apocalyptic as it may seem, you don't have to worry.
00:23 If you are about 30 years old, you have already experienced this phenomenon more than once because the sun is inverted every 11 years.
00:31 You probably didn't notice any changes at the time because this process has no major impact on terrestrial life.
00:37 But this time, things could be a little different.
00:42 On Earth, sea currents are movements that play a crucial role in influencing the climate and the weather and distributing the heat of the equator to the poles.
00:51 On the sun, these currents are more like a plasma ocean.
00:55 But they do not only transport heat, they also transport electromagnetic energy.
01:00 This happens because the sun is a huge ball of incandescent and ionized gas that continues to circulate inside its nucleus.
01:09 By fusing these hydrogen atoms to form helium, our star releases a huge amount of energy, producing these powerful electric currents.
01:18 And every time you have such currents, you have magnetic fields.
01:22 It's easier to visualize if you think back to this classic experiment with a copper wire and a nail that you probably made at school.
01:30 When an electric current passes through a wire, it creates a magnetic field around it.
01:35 So when you connect a wire to a battery and wrap it around a nail, this nail becomes magnetized.
01:41 It's similar to the way electric currents generate magnetic fields around the sun.
01:48 The whole process that generates magnetic fields in the sun is what we call a dynamo.
01:56 We can't see it directly, but we can see the effects on the surface of the sun.
02:01 When plasma and magnetic flows become unstable, they manifest in the form of solar torches.
02:07 You know, those dark areas on the surface of the sun.
02:10 We still don't know much about how this dynamo works, but scientists have understood something important after observing these solar torches over the centuries.
02:20 This process follows a certain pattern.
02:22 Every decade, it reorganizes itself.
02:26 The magnetic fields of the poles of the sun diminish until they completely disappear, then they return, but with an opposite polarity.
02:34 In the 1950s, researchers discovered that when the solar torches began to intensify, it meant that the poles were preparing for an inversion.
02:43 And in recent years, solar activity has been completely out of the ordinary.
02:47 More solar eruptions, electromagnetic radiation bursts, and more plasma ejections into space.
02:54 It's as if we were sitting in the first row of the largest pyrotechnic show in the solar system.
02:59 In fact, the sun has probably not been so animated over the last two decades.
03:04 At present, experts believe that the magnetic fields of the poles are almost synchronous and are weakening little by little, getting closer and closer to zero.
03:14 But we have not yet reached the point of inversion.
03:19 Although it may seem that the sun reverses its poles every 11 years, like a clock, the truth is that it is not so clearly defined.
03:26 This path is not without obstacles, and some aspects of the phenomenon are still very difficult to predict.
03:32 Take the last solar cycle, for example.
03:35 The northern hemisphere began its magnetic inversion as early as June 2012, but then encountered an obstacle and stagnated around the neutral point until the end of 2014.
03:45 During this time, in the southern hemisphere, things are much more fluid, and the change in polarity is happening in 2013.
03:52 This time, solar activity seems more regular. Things seem to be happening more smoothly during this cycle, with a more uniform transition of poles.
04:00 But here's the thing, this inversion process never repeats itself, and that's what makes this phenomenon so interesting to observe.
04:08 But at the same time, it is difficult to predict how this will affect us down here.
04:14 Here on Earth, we have no war to worry about these intense solar explosions, which occur at 150 million kilometers away.
04:22 But if, and we say "if", a solar storm were to hit our planet, the main threat it would pose would probably be the disruption of space communication satellites.
04:33 However, things could take a different turn during the cycle of inversion planned for 2024, because the number of satellites in orbit has exploded in recent years.
04:42 The Starlink system, for example, involves more than 4,000 of them.
04:47 All these communication satellites and other GPS could be impacted, or even destroyed, by a powerful solar storm.
04:55 Although the chances of a powerful solar storm hitting Earth are slim, it is not impossible.
05:03 In 1859, during the Carrington event, a storm occurred near a peak of solar activity,
05:09 causing overvoltages in the telegraphic lines, triggering fires and disrupting exchanges worldwide.
05:16 The Earth was silent when all these telegraphic communications were cut off.
05:21 Just imagine what a solar storm could do to our vast fleet of satellites today.
05:26 It could affect everything we depend on daily, from geolocation and space-based telecommunications to weather forecast services.
05:35 Electricity distribution on the ground could also be affected.
05:40 You can make a cross on YouTube, and even a nice one.
05:43 Because if such an event occurred today, it could put the Internet to bad use, cutting off countless people from the world.
05:50 Predictions say that if a Carrington-type event occurred today, it would result in damage worth 600 to 2,600 billion dollars.
05:59 And we are talking here only about the United States.
06:02 Fortunately for us, solar storms as intense as the Carrington event only occur once every 500 years or so.
06:09 Bad news for telecommunications satellites, but excellent news for the observers of Boreal auroras.
06:17 During the Carrington event, dazzling auroras illuminated the sky and the spectacle of the polar lights spread far beyond the usual boundaries.
06:26 These Boreal auroras were seen to the south of Cuba and Honolulu,
06:31 while australian auroras were seen to Santiago, Chile.
06:35 For many people around the world, this was their first sight of such auroras, leaving them stunned in front of these unusually bright skies.
06:43 Some then thought it was the end of the world, while others woke up unusually early,
06:48 believing that the sun had risen after hearing the birds chirping and all that light.
06:53 Today, we know that there is nothing strange about this,
06:56 given that the appearance of auroras at such latitudes is one of the expected effects of the inversion of the magnetic poles of the sun.
07:03 Typically, these iridescent phenomena are observed between 60 and 75 degrees of latitude,
07:09 but during the last inversion of the magnetic poles, in 2013, intense auroras were observed below 50 degrees.
07:18 Witnesses described these auroras as being "red blood" shooting on the skull and shining so brightly that one could read a newspaper in their own light.
07:27 It is important to study this phenomenon rather than fear it.
07:32 The inversion of the magnetic poles of the sun is actually a perfect opportunity for scientists to better understand how our star works.
07:39 And as there are still many pieces missing from the puzzle of solar dynamo,
07:43 we are still not able to understand why some cycles are more intense than others,
07:49 or to predict when an ejection of coronal mass will occur exactly.
07:53 But being able to predict them becomes more and more crucial as we venture into space.
07:59 The more people there are in orbit around the Earth, the more they are exposed to these strong solar storms.
08:04 This is why the scientific community is trying to learn more precisely when such a storm could cause damage to our spaceships and stations.
08:13 In addition, this would help meteorologists to make better predictions, not only on Earth, but also in space.
08:21 The main goal would be to make space travel safer as our interest in missions to the Moon and Mars continues to grow.
08:29 Another reason why it would be important to learn more about the inversion of the poles of the sun
08:35 is to better understand how the mysterious heart of our star works.
08:39 This could indeed help us better grasp the aspect of other stars in the universe,
08:44 and perhaps bring us closer to the answer to the ultimate question.
08:47 What are we doing here?
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