Sao Paulo
NASA's Solar Dynamics Observatory, the US space agency, reported that the largest solar flare since 2017 occurred last Thursday afternoon (14), causing telecommunications outages in parts of South, Central and North America due to the enormous amount of radiation emitted .
According to the observatory, it was an explosion of category X2.8. Solar flares are classified by their intensity, ranging from Class B (weakest) to C, M and X (strongest). Each change in letter ranking represents a tenfold increase in energy. And within each letter, the scale is divided into numbers from 1 to 9, with 1 representing the weakest class and 9 the strongest class.
The last major eruption occurred in September 2017: an X8.2.
During these explosions or solar flares, energetic particles are emitted and move at speeds very close to the speed of light. Therefore, they reach Earth in about eight minutes, increasing radiation. They are discovered by Goes, the NASA satellite used to study the sun and space weather.
In addition to highenergy particles, solar flares also release coronal mass ejections (CME), which are clouds of plasma that travel longer in space and take about two to three days to reach Earth. Therefore, there is an expectation that this CME could arrive on Earth this Sunday (17) and cause a geomagnetic storm.
“CMEs are plasma clouds that have an intense magnetic field and are typically dozens of times larger than Earth. When they interact with the Earth's magnetic field, they cause geomagnetic storms,” explains Marcel Nogueira de Oliveira, professor at the Institute of Physics UFF (Fluminense Federal University).
Oliveira emphasizes that although these events are rare, they are usually part of the 11year solar cycle, mainly at the peak of stellar activity, the socalled solar maximum, which should occur in 2024. “The difficulty in predicting them lies precisely in what constitutes them.” The study of solar physics and space weather is so important and essential today.
Scientists at the Space Weather Prediction Center of the United States Oceanic and Atmospheric Agency (NOAA) are still analyzing whether the CMEs from Thursday's (14) solar flare were aimed at Earth. If so, the effects will only be known when they reach our planet.
The regions most vulnerable to the effects of these solar storms are the poles, where the Earth's magnetic field is smaller. The most visible form of these phenomena is the Aurora Borealis, colorful and bright clouds that appear when the magnetic field receives the storm. However, experts say there is no need to worry as the storm produced is expected to be at level G1 or G2, the lowest level on the NOAA scale, which goes up to G5.
“I believe it is possible that under certain conditions an X2 solar flare can produce a CME, which in turn can trigger a G5 geomagnetic storm on the NOAA scale. But the extent of the problems that a G5 storm can cause is very specific and depends on several factors,” says Oliveira, emphasizing two important points:
1) Larger solar flares like an X9 are events that release more energy and therefore have a greater chance of producing a larger and faster CME. Therefore, solar flares of greater magnitude, such as one, are more likely
2) G5 level geomagnetic storms tend to be very rare, so they have not yet occurred in the current solar cycle 25, nor did they occur in the last solar cycle, cycle 24. The last storm of this type was observed in solar cycle 23, when there were about 13 storms of this size.
If the geomagnetic storm is strong enough, it can cause significant disruption to radio communications, power grids, satellites or spacecraft. In 1859, the largest in history, power surges crippled the world's telegraph systems and disrupted communications.
“The more we know about the Sun and how the structures of CMEs propagate through the interplanetary medium, the better we can predict and mitigate the occurrence of an extreme event of this type with good margin in advance.” “A better understanding of our host star is for ours “It is of crucial importance to modern lifestyles that are heavily dependent on satellites and means of communication,” concludes the physicist.
Check out the effects of geomagnetic storms on Earth:
G1 (LOW) FREQUENCY OF 1,700 CASES PER 11YEAR CYCLE OF THE SUN
- Energy systemsNote: Slight fluctuations in the power network may occur.
- Space operations: Possible minor impact on satellite operations.
- Other systems: Above these concentrations, migratory animals are affected; Aurora is often visible at high latitudes (near the North Pole).
G2 (MEDIUM) FREQUENCY OF 600 PER CYCLE
- Energy systems: Power grids at high latitudes may experience voltage alarms and prolonged storms may cause damage to transformers.
- Spacecraft operations: Corrective action in steering may be required by ground control; Possible changes in air resistance affect orbit predictions.
- Other systems: The propagation of highfrequency radio waves can become weaker at higher latitudes, and auroras have been observed at low altitudes such as New York and Idaho (typically at 55° geomagnetic latitude).
G3 (STRONG) FREQUENCY OF 200 PER CYCLE
- Energy systems: Voltage corrections may be required, some protection devices may cause false alarms.
- Space operations: Surface charges may occur on satellite components; For low Earth orbit satellites, air resistance may increase and corrections may be necessary if orientation problems occur.
- Other systems: There may be intermittent problems with satellite navigation and low frequency radio navigation. High frequency radio can be intermittent, and auroras have been seen as far away as Illinois and Oregon (typically 50° geomagnetic latitude).
G4 (HARD) FREQUENCY OF 100 PER CYCLE
- Energy systems: Possibly widespread voltage regulation problems and some protection systems may erroneously disconnect the network.
- Spacecraft operations: There may be loading and tracking issues on the surface. Corrections may be necessary if there are problems with orientation.
- Other systems: Induced currents in pipelines influence preventive measures; sporadic highfrequency radio propagation, satellite navigation affected for hours, lowfrequency radio navigation disrupted, and auroras observed as far south as Alabama and northern California (typically at 45° geomagnetic latitude).
G5 (EXTREME) FREQUENCY OF 4 PER CYCLE
- Energy systems: There may be widespread voltage regulation and protection system problems, some grid systems may experience a complete failure or a power outage. Transformers can be damaged.
- Spacecraft operations: There may be heavy surface loading, problems with orientation, communications during ascent and descent, and satellite tracking.
- Other systems: Currents in channels can reach hundreds of amperes, propagation of highfrequency radio waves may be impossible in many areas for one to two days, satellite navigation may be affected for days, lowfrequency radio navigation may be out of range. Air for hours and auroras were seen as far away as Florida and South Texas (typically 40° geomagnetic latitude).
Source: United States Oceanic and Atmospheric Agency (NOAA)