As Earth completes yet another full orbit around the Sun, an encroaching storm is expected to bathe the planet in a glorious glow of auroral light.
On December 29 and 30 , the Sun unleashed a series of huge eruptions, flares, and coronal mass ejections, possibly right in our direction.
The flash of electromagnetic radiation caused brief radio blackouts on our planet’s dayside just 8 minutes after leaving the Sun. But coronal mass ejections (CMEs) are huge eruptions of plasma that take hours to days to follow as they billow out through the Solar System.
On reaching us, CMEs slam into Earth’s magnetic field, resulting in an event known as a geomagnetic storm – the most spectacular effect of which is the multi-hued aurorae that shimmer across the sky at high latitudes around the planet’s poles.
The three eruptions in question took place over the course of 29 and 30 December 2024 UTC. On December 29, the Sun produced an X1.1 flare from sunspot region AR 3936. X-class flares are the most powerful class of flares. Then, on December 30, an X1.5 flare from the same region was followed by an X1.1 flare from sunspot region AR 3932.
Meanwhile, smaller flares popped up all over. There were 18 M-class flares – the second-most powerful category – counted on December 29 .
The CMEs are another matter. These are often released at the same time as flares, but the one that may be responsible for a geomagnetic storm on December 31 was recorded an hour prior to the first flare on December 29.
A second, smaller CME was recorded later the same day, with the possibility of a less powerful geomagnetic storm on January 1.
Lot’s of activity on the Sun today! Many M-class solar flares and even an X1 solar flare! This coronal mass ejection which left the Sun at 6 UTC is the talk of the town today and is the reason why the NOAA SWPC issued a strong G3 geomagnetic storm watch for 31 December. However… pic.twitter.com/rIA2Mh9jVt
— SpaceWeatherLive (@_SpaceWeather_) December 29, 2024
The NOAA has issued an alert for a powerful geomagnetic storm, but there are some caveats. Neither CME is expected to deliver a full frontal blow to Earth, which makes forecasting difficult.
And, as SpaceWeatherLive points out, based on the data we have, it’s unclear whether the coronal mass ejections took place on the side of the Sun facing us at all. It’s possible they erupted from the Sun’s far side, in which case they’re not headed our way at all.
Which, when you think about it, is perfect. What better way to end the year than a practical joke played by the Sun?
Keep an eye on the NOAA’s Space Weather Prediction Center for updates.