Solar Cycle Maximum, here we come. The Sun’s activity is truly picking up steam, meaning more sunspots, coronal holes, and even solar flares. The strongest yet for the current solar cycle, Cycle 25, is an X 2.8 class flare: the strongest recorded since September 10, 2017, and about 5 to 10 percent of the strongest on record from November 2003.
The location of the flare was above the sunspot AR 3514, and while it was not directly facing our planet, we were hit by the energetic release. The solar flare created a radio blackout, and was one of the strongest radio events from the Sun ever recorded according to the Space Weather Prediction Center (SWPC) of the National Oceanic And Atmospheric Administration.
The effects of the radio blackout were on the Sun-facing portion of the planet at the time (December 14, 5:02 pm UTC), so across the Americas. It was strongest over South America, but the SWPC reports radio communication interference over the United States.
“These blackouts can lead to temporary degradation or complete loss of high frequency radio signals. This is the largest flare of this solar cycle and since Sep 10, 2017, when an X8.2 flare was observed at GOES-15,” a statement from SWPC reads. “This sunspot region will be monitored closely by SWPC forecasters given its potential to produce additional M-class and greater flares.”
The X 2.8 flare was preceded by a weaker M-class flare from the same sunspot. While weaker, it was still able to create some moderate radio interference across the sunlit portion of the Earth, which at that point was Europe, Africa, and portions of Asia.
The Sun goes through a cycle of activity that lasts 11 years. At solar maximum, there is the best chance to have strong flares and powerful coronal mass ejections that can lead to all sorts of space weather effects on the Earth, including radio blackouts and gorgeous northern and southern lights.
The current cycle is expected to peak between January and October of 2024. Official predictions are usually put forward when the Sun is at its minimum. So in 2019, it was estimated that the maximum was going to be reached in July 2025.
These predictions need to balance the consensus of different models initially, and given how quiet cycle 24 was, it might have affected some models more than others. Not all of the models though. A new prediction approach did expect an earlier, more active cycle in a paper that was released in April. Solar flares such as this are continuing to prove the authors right.