00:00About a year ago, an exceptional event took place on Mars.
00:04Its magnetic shield and the surrounding atmosphere expanded,
00:08reaching a size about three times higher than their usual dimension.
00:12The Earth has already witnessed a similar phenomenon,
00:15notably in 1989.
00:17This event has led to a spectacular expansion of our magnetosphere,
00:21reaching up to 100 times its normal size.
00:24Scientists warn that the Earth could once again experience such a situation.
00:29But on an even bigger scale.
00:31And the repercussions could be disastrous.
00:34Let's examine the reasons for this phenomenon
00:37and the consequences it could have.
00:39The space probe MAVEN, developed by NASA,
00:43has been orbiting Mars since 2014.
00:45This unique device is the only one to simultaneously monitor solar activity and that of Mars.
00:50On December 26, 2022,
00:52it witnessed a captivating event taking place on the Red Planet.
00:56The Martian atmosphere and its magnetic shield suddenly took on an unexpected magnitude,
01:01stretching for thousands of kilometers.
01:03According to scientists, such an event is of exceptional intensity and rarity,
01:08and MAVEN was able to capture it every moment.
01:10In trying to understand this anomaly,
01:12researchers have come up with a fascinating link.
01:15This phenomenon was directly related to solar wind.
01:19Solar wind is a flow of particles projected by our star,
01:22composed mainly of protons and electrons from the external atmosphere of our star,
01:27it moves at a dizzying speed,
01:29reaching 800 km per second.
01:32These charged particles propagate throughout the solar system in the form of plasma.
01:37Mars, just like the other planets in our solar system,
01:40is constantly exposed to this solar wind.
01:42Imagine it as a kind of continuous breath coming from our star.
01:47This wind exerts pressure on the Martian magnetic shield,
01:50called the magnetosphere,
01:51and contributes to the progressive erosion of the Martian atmosphere in space.
01:55Researchers have established that the huge expansion observed on Mars
01:59was due to a vacuum,
02:00unusual in the atmosphere.
02:03A fast solar wind caught up with a slower wind,
02:05causing a compression and thus creating a vacuum zone in the Martian atmosphere.
02:10This exceptional configuration triggered a fast and spectacular expansion of the magnetosphere.
02:16The Sun follows a cycle of about 11 years,
02:19alternating between a phase of low activity, called the solar minimum,
02:24and an intense phase of activity,
02:26called the solar maximum,
02:28before returning to its initial state.
02:31This phenomenon was observed in the 18th century,
02:34and we are currently in the 25th century.
02:37This cycle is linked to the magnetic field of the Sun.
02:40At the solar minimum, this field is powerful and structured.
02:43However, it weakens little by little,
02:45until the solar activity suddenly increases.
02:48This intensification generates solar winds,
02:51which project particles jets towards the planets,
02:54including the Earth.
02:55In 1999, the solar wind almost completely disappeared for three days,
03:00an event that could occur again soon.
03:03Scientists estimate this time that it could occur earlier
03:06and with an increased intensity.
03:08The Sun then becomes particularly active,
03:11releasing burning plasma,
03:13forming huge dark spots and emitting powerful radiation.
03:17And alas,
03:19the next solar maximum seems to have taken the scientific community by surprise.
03:23Initially planned for 2025,
03:26this solar storm seems to arrive faster than expected,
03:29taking scientists by surprise.
03:31The number of observed solar spots has far exceeded expectations.
03:34In 2022,
03:36the Sun reached a peak of solar spots over 8 years,
03:39followed, in 2023,
03:41by a doubling of the expected number of these formations.
03:43And that's not all.
03:45Solar eruptions also know a recrudescence.
03:48In March,
03:49a geomagnetic storm illuminated the skies
03:51with spectacular auroras visible in 30 American states,
03:55marking the most intense event of the last six years.
03:58Rare solar phenomena are also becoming more frequent.
04:01Among them,
04:02a huge plasma cascade,
04:04a polar vortex around the north pole of the Sun that lasted for hours,
04:08and a solar tornado extending over three days
04:11and culminating at a height equivalent to 14 times the diameter of the Earth.
04:15These growing solar activities pose risks for our planet.
04:19Solar storms can disrupt communications,
04:22damage electrical systems,
04:24cause power outages,
04:26and directly threaten living beings.
04:28They can also ionize the Earth's atmosphere,
04:31interfering with radio signals and GPS systems.
04:35If these disturbances coincide with natural disasters such as earthquakes or tsunamis,
04:40the consequences could be disastrous.
04:43In addition,
04:44powerful solar storms can generate electric currents
04:48capable of degrading essential infrastructures,
04:50such as electrical networks and railway lines.
04:53Aircraft passengers could be subjected to higher levels of radiation during solar storms.
04:59It is difficult to assess the exact consequences on their health.
05:03However,
05:04astronauts on board spacecraft,
05:06such as the International Space Station,
05:09could run much greater risks.
05:11Future missions will therefore have to integrate solar cycles into their planning.
05:16We are not the only species in danger.
05:18These storms can disrupt animal migrations,
05:21such as gray whales,
05:22sea turtles,
05:23and birds
05:24that rely on the Earth's magnetic field to orient themselves.
05:27And,
05:28cherry on the cake,
05:30the risk of potential collisions between satellites.
05:33Commercial space companies often favor the speed of launch to safety,
05:38thus neglecting the impact of space meteorology.
05:42During solar storms,
05:43the high ionized atmosphere exerts an increased drag on satellites in orbit.
05:48In the event of a problem,
05:49some could deviate from their trajectory and collide,
05:53or even fall back to Earth.
05:55The most impressive known solar storm is the 1859 Carrington event.
06:00This geomagnetic storm of unequal intensity
06:04illuminated the sky with visible auroras from the poles to Cuba and Japan.
06:09In the United States,
06:10their burst was such that gold diggers woke up in the middle of the night,
06:14thinking it was day.
06:15This storm was caused by a major solar eruption.
06:19Although the auroras were a breathtaking spectacle,
06:22their consequences were serious.
06:24The telegraphic systems of Europe and North America were disrupted.
06:29The pylons produced sparks,
06:32operators suffered electrical discharges,
06:35and equipment began to work thanks to the only auroral current,
06:39in the absence of batteries.
06:40Similar storms have occurred at least three times in history,
06:44causing the same devastation.
06:46Today, an event of this magnitude could cost between 600 and 2,600 billion dollars,
06:52just in the United States.
06:53Researchers will continue to analyze past events and data from ice cores,
06:58to better understand and anticipate the impacts of future solar storms.
07:02Although the behavior of our star remains unpredictable,
07:05it emphasizes the importance of deepening its study.
07:08The probability that the next storm will reach the intensity of a Carrington event is low.
07:13However, by taking advantage of this time to prepare,
07:17its effects could go unnoticed.
07:19Preparations generally consist of adjusting the trajectories of satellites,
07:23immobilize planes on the ground and locate sensitive infrastructures.
07:27During this time, we continue our exploration of Mars.
07:30The Martian atmosphere is very different from ours.
07:33On Earth, the air is breathable,
07:35mainly composed of nitrogen, oxygen and various other gases.
07:39However, the atmosphere of Mars contains extremely high levels of carbon dioxide.
07:45While on Earth, carbon dioxide accounts for less than 1%,
07:49on Mars, it accounts for about 96% of the atmosphere.
07:53In addition, the Earth's atmosphere is more than 100 times denser than that of Mars.
07:58Even though Mars is about twice as small as Earth,
08:01its atmosphere is incredibly thin, comparable to a pen compared to our air.
08:06However, it has not always been so.
08:09In the past, Mars could have looked like Earth.
08:12It turned out that it had water,
08:14and it was even possible that it was home to plants.
08:17If we added water to Mars today, plants could grow there.
08:21In the distant past, Mars experienced an intense period of volcanism,
08:25suggesting that it had a thick atmosphere and perhaps even a vast ocean.
08:29Although we do not know what happened to it, some theories exist.
08:33For example, although Mars has a magnetic field,
08:36it is very weak, which would have allowed the solar wind to sweep its atmosphere.
08:41Finally, it became the red, cold and dusty planet that we know today.
08:46NASA's Perseverance rover recently celebrated its 1,000th day on Mars,
08:51making remarkable discoveries.
08:53It crossed an ancient network of rivers and Martian lakes,
08:57collecting 23 precious samples.
08:59The latter will allow us to better understand the history and geology of the planet.
09:04Extreme phenomena, although intimidating,
09:06allow us to deepen our knowledge of the solar system.
09:10Fortunately, thanks to its robust design,
09:13MAVEN is able to resist violent solar storms,
09:16thus offering the opportunity to study Mars when it is deprived of its natural protection.
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