Nov. 30, 2020: Yesterday (Nov. 29th at 1311UT), Earth-orbiting satellites detected the biggest solar flare in more than 3 years. NASA’s Solar Dynamics Observatory recorded this extreme-ultraviolet movie of the M4.4 category blast:
X-rays and UV radiation from the flare ionized the top of Earth’s atmosphere, producing a shortwave radio blackout over the South Atlantic: map. Ham radio operators and mariners may have noticed strange propagation effects at frequencies below 20 MHz, with some transmissions below 10 MHz completely extinquished.
Remarkably, this flare was even bigger than it seems. The blast site is located just behind the sun’s southeastern limb. As a result, the explosion was partially eclipsed by the body of the sun. It might have been an X-class event.
The flare also hurled a significant coronal mass ejection (CME) into space, shown here in a coronagraph movie from the Solar and Heliospheric Observatory (SOHO):
Update: At first it appeared that the CME would completely miss Earth. However, NOAA analysts believe that the outskirts of the cloud might deliver a glancing blow to Earth’s magnetic field on Dec. 1-2. If so, the impact could spark a minor G1-class geomagnetic storm with auroras over northern countries such as Canada, Iceland, Norway and Sweden.
It would be a different story if the main body of the CME hit. Then we would be anticipating a strong geomagnetic storm. Maybe next time!
“Next time” could be just days away. The hidden sunspot that produced this major event will rotate onto the Earthside of the sun during the next 24 hours or so. Then its ability to spark geomagnetic storms will be greatly increased. Instant solar flare alerts: SMS Text.