On May 15, it was reported that at 0:51 Beijing time on May 15, the NASA Solar Dynamics Observatory (SDO) probe captured an X8.7 solar flare, originating from the sunspot group 3664, which is the largest flare so far in this round of solar activity cycle and the largest flare since 2005.
Fortunately, however, the flare appeared on the side facing away from the Earth, which did not have a noticeable impact on humans, and the continent was late at night, so the ionospheric environment above was not greatly affected.
The 25th solar cycle, which began in December 2019 and is now approaching its maximum, will see more and more eruptions of such flares, if not stronger, and the frequency and intensity of auroras will increase.
The National Oceanic and Atmospheric Administration (NOAA) bluntly said: "It's not over yet!" ”
Last week, the Sun has erupted with multiple X-class flares, as well as the second-highest M-class flare, with the X2.2 magnitude on May 9 clearly threatening power and communications on Earth and in orbit, as well as causing massive auroras.
Last weekend's strongest geomagnetic storm in 20 years also caused one of NASA's satellites to unexpectedly rotate at a reduced altitude and enter "safe mode," or protective hibernation.
Even the seven astronauts on the International Space Station were moved to an area with better radiation shielding.
The average solar cycle is 11 years, and was discovered by the German amateur astronomer Schwarzschild in 1843 that the sun's magnetic field flips completely once in each cycle.
Solar flares are divided into five levels from low to high: A (close to the cosmic background level), B, C, M, and X, with each higher level increasing the energy output by a factor of 10.
Each level is subdivided into nine levels from 1 to 9, with each level increasing energy output by 1 time.
For example, X9 has 10 times the energy output of X1, and X1 has 10 times the energy output of M1.
On November 4, 2003, there was an astonishing X45-class solar flare, releasing energy equivalent to the simultaneous explosion of 450 billion hydrogen bombs.