An unexpected solar explosion caused communication disruptions on Earth: this is just the beginning (video).
Even though the Sun has entered a solar maximum phase, which is the period of its highest activity, astronomers have not observed any X-class flares recently. This changed on Sunday, December 8, when a significant release of radiation and energy occurred in the form of an X2-class flare. This event led to partial radio communication outages on our planet, but a geomagnetic storm is expected to follow, according to Space.
During a solar maximum, which occurs roughly in the middle of the 11-year solar activity cycle (the current 25th cycle began in 2019), the number of sunspots on our star increases. These special dark regions with strong magnetic fields cause bursts of energy and radiation in the form of solar flares. Astronomers believe that the solar maximum, which began in November of this year, will last at least until the end of 2025. Despite this period of heightened solar activity, astronomers had not observed any X-class flares for a long time.
The new X2-class flare originated in the sunspot region known as AR 3912 on Sunday, December 8. The NASA GOES-R spacecraft monitored this flare and captured impressive images of the event.
Geomagnetic Storm on December 11
According to physicist Tamita Skov, who monitors space weather (which is influenced by solar activity), a coronal mass ejection accompanied the X2-class flare, which is a flow of magnetized plasma. This flow is currently heading towards Earth, although it is likely to only partially affect our planet based on available observational data. In any case, even a slight impact on Earth's magnetosphere from the solar plasma flow could lead to a geomagnetic storm as early as Wednesday, December 11. Thus, we can expect to see very bright auroras even at lower latitudes, not just in polar regions. However, predicting the onset of a geomagnetic storm is quite challenging, so scientists will likely only learn of its occurrence after it happens.
Classes of Solar Flares
Scientists categorize all solar flares into five classes: A, B, C, M, and X. Each class is ten times weaker than the next one, starting from class A. Flares of class A and B have no impact on our planet. Class C and M flares can have some effects. However, the most dangerous for Earth are X-class flares. They can disrupt satellite operations in orbit and cause problems with radio communication on Earth. Each class of flares has numerical designations that indicate the approximate strength of the flare. While the first four classes are limited to a power range of 1 to 10, X-class flares have no such restrictions.
Why Do Communication Outages Occur on Earth After a Solar Flare?
The new X2-class solar flare caused a temporary radio communication outage over southern Africa. Such issues arise because, during a solar flare, intense X-ray and ultraviolet radiation is generated.
This radiation reaches Earth in less than 10 minutes, as it travels through space at the speed of light. As a result, the radiation ionizes the upper layers of Earth's atmosphere. Ionization increases the density of the atmosphere, hindering the normal propagation of shortwave radio signals. When radio waves pass through the electrically charged, ionized layers of the atmosphere, they lose energy due to more frequent collisions with electrons, which can completely absorb the radio signals.