00:00On July 23, 2024, the Solar Orbiter space probe, operated by the European Space Agency,
00:07detected a solar eruption of exceptional power coming from the hidden face of the Sun.
00:13Although it is not the most intense ever observed,
00:16it is undeniable that we had an incredible chance of not suffering the devastating effects.
00:21Such eruptions often cause violent and persistent radiation storms.
00:26If it were to go to Earth, it could cause power cuts worldwide.
00:33Before examining this potentially catastrophic solar eruption in more detail,
00:38it is essential to understand the nature of this phenomenon.
00:41Solar eruptions result from the incessant movement of magnetic fields in the atmosphere of our star.
00:46When the Sun approaches its maximum solar, the most active phase of its 11-year cycle,
00:52which, by the way, corresponds to the current period,
00:56these magnetic fields interweave more and more,
00:59transforming our star into a gigantic sphere of intertwined magnetic wires.
01:04These fields intersect, intercut, and end up reconnecting.
01:09Have you ever observed iron filings around a magnet?
01:12They align according to the magnetic force lines.
01:15Similarly, the burning plasma that covers the surface of the Sun
01:20is influenced by these same lines of force.
01:22Sometimes, when the magnetic fields interact,
01:26a part of the plasma detaches,
01:28accelerating these particles at dizzying speeds
01:31and releasing intense radiation into space.
01:34This is what we call a solar eruption.
01:37Other times, our star projects huge amounts of matter
01:41during phenomena called coronal mass ejections, or EMC.
01:45Only one of these ejections can contain up to 20 billion tons of matter.
01:50If this matter was made up of rock,
01:52it could form a mountain 400 meters in diameter and nearly 800 meters in height.
01:57This ejected material often travels through space at speeds exceeding 1.6 billion kilometers per hour.
02:04Solar eruptions and coronal mass ejections
02:07are among the most violent events in the solar system,
02:10releasing unimaginable amounts of energy.
02:13Solar eruptions are classified according to their intensity.
02:16The weakest belong to classes A and B,
02:19followed by classes C and M,
02:21while the most powerful eruptions are classified in the X category.
02:25Each letter is accompanied by a number ranging from 1 to 9,
02:28and sometimes even a higher number,
02:30in the same way as the Richter scale used for earthquakes.
02:33Class A and B eruptions are too weak to affect our planet.
02:38On the other hand, class C eruptions can cause light effects,
02:42albeit perceptible.
02:43Class M eruptions can cause radio-temporal interruptions at the poles
02:47and trigger moderate radiation storms,
02:50potentially dangerous for astronauts.
02:52However, the most formidable are class X eruptions.
02:56Some eruptions are more than 10 times more powerful than a class X.
03:00This is why the classification of class X eruptions can exceed the number 9.
03:05Let's go back to this recent solar eruption.
03:07It belonged to class X-14.
03:10We already know that this corresponds to an eruption of exceptional intensity.
03:14Among the other major eruptions recently detected by astronomers,
03:18we note an eruption of class X-12 that occurred on May 20,
03:21as well as an eruption of class X-10 observed on July 17.
03:25All these eruptions came from the hidden side of the Sun.
03:28Concerning the side of our star facing the Earth,
03:31the most intense solar eruption observed so far in this solar cycle
03:35occurred on May 14.
03:37It was an eruption of class X-8.7,
03:40which caused radio interruptions.
03:42A few days earlier, a powerful geomagnetic storm,
03:45accompanied by spectacular aurorae visible throughout the world,
03:49had already occurred, resulting in powerful coronal mass ejections.
03:53As for the eruption of class X in July,
03:55its power was such that it could have disastrous consequences for us.
04:00Fortunately, the plasma explosion,
04:04was not directed towards the Earth.
04:07If this had been the case,
04:09we would have witnessed a solar storm of considerable magnitude.
04:12The Boreal auroras would have been breathtaking,
04:16but also a sign of a certain terror.
04:18However, such an explosion of energetic particles projected towards the Earth
04:23could have caused major technological disruptions
04:26and electrical breakdowns,
04:28similar to the 1989 event
04:30that seriously damaged Quebec's power grid,
04:33or a much older disaster,
04:35which, despite everything,
04:37had caused significant damage worldwide.
04:40We refer to the Carrington event,
04:43which occurred in 1859,
04:45which constitutes the first documented solar eruption
04:48to have impacted our planet.
04:50This event occurred on September 1,
04:52and bears the name of Richard Carrington,
04:55the solar astronomer who observed the eruption through his own telescope
04:58and drew the visible solar spots on the surface of our star.
05:02According to scientists,
05:04this eruption remains the most powerful documented solar storm
05:07in the last five centuries.
05:09The Carrington event caused visible auroras
05:12all the way to the south of the Caribbean.
05:14It also caused major disruptions
05:16to telegraphic services around the world,
05:19electrocuting some operators
05:21and causing fires
05:23after electrostatic discharges
05:25ignited the paper used for transmissions.
05:28Another major solar eruption,
05:30which occurred on August 4, 1972,
05:32disrupted long-distance telecommunications
05:36in several American states,
05:38including Illinois.
05:39This incident led the American Telephony and Telegraphy Company
05:43to completely review its power system
05:45for transatlantic cables.
05:47Then, on March 13, 1989,
05:50two extremely powerful coronal mass ejections
05:54caused a geomagnetic storm
05:56that led to a power outage in Canada.
05:58This cut left about 6 million people
06:01without electricity for nine hours.
06:04It is reported that this solar eruption
06:06disrupted the electricity transmission network
06:08of the Hydro-Québec power station
06:10and damaged some electric transformers in New Jersey.
06:13However, despite its magnitude,
06:15this solar storm was nothing compared
06:17to the intensity of the Carrington event.
06:20The July 14 solar storm
06:22occurred on the day of our national holiday,
06:24in the year 2000.
06:25It was a class X5 event
06:28that caused short circuits in several satellites
06:31as well as radio cuts.
06:32This episode remains
06:34one of the most studied solar events to date.
06:37Between October and November 2003,
06:39our star emitted a series of major solar eruptions
06:42and coronal mass ejections
06:44that hit the Earth, striking its atmosphere.
06:47These solar storms,
06:49known as the Halloween Storm of 2003,
06:51led to the detour of certain flights
06:54affecting satellite systems
06:56and causing power outages in Sweden.
06:58In addition, the solar and heliospheric observatory
07:01was unable to fulfill its functions
07:03during this intense solar episode.
07:05On October 28, 2003,
07:07the sun emitted a solar eruption
07:09of considerable magnitude
07:11towards the Earth.
07:12It was so intense
07:14that it saturated the sensor of the space probe
07:16that measured it,
07:17the latter reaching its limit at X28.
07:20Later, scientists determined
07:22that the eruption had actually reached
07:24a maximum intensity of about X45.
07:26What made the Halloween storms
07:28particularly disturbing
07:30is that they occurred during a period of the solar cycle
07:33where the activity is usually calm,
07:35i.e. 2 to 3 years after the maximum solar.
07:37According to NASA statistics,
07:39only 17 powerful solar eruptions
07:41took place during this period.
07:43On December 5, 2006,
07:45the sun emitted a new class X9 solar eruption.
07:49This eruption disrupted communications
07:51between satellites and the Earth
07:53as well as GPS navigation signals
07:55for about ten minutes.
07:57The storm was so powerful
07:59that it even damaged the radiographic imager
08:01of the satellite GOES-13,
08:03affecting several pixels of its detector.
08:05In February 2022,
08:07SpaceX suffered the formidable power
08:09of our star
08:11when a geomagnetic storm
08:13destroyed 38 Starlink satellites,
08:15representing losses of several tens of millions of dollars.
08:18This disaster occurred
08:20shortly after their orbit.
08:22Unfortunately, Starlink satellites
08:24are particularly vulnerable
08:26to geomagnetic storms
08:28due to their extremely low orbits,
08:30located between 100 and 200 km.
08:32They depend on their engines
08:34to counter the atmospheric drag
08:36and reach their final altitude
08:38of about 560 km above the Earth.
08:40During a geomagnetic storm,
08:42the Earth's atmosphere absorbs
08:44the energy of the storm,
08:46warms up and extends to the heights.
08:48This leads to an increase
08:50in the density of the atmosphere,
08:52which increases atmospheric resistance
08:54and can represent a major risk
08:56for satellites.
08:58That's exactly what happened.
09:00The new Starlink satellites
09:02failed to compensate for this increased drag
09:04and began to fall back,
09:06ending up burning in the atmosphere.
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