***UPDATE: the X9 has finally arrived (Monday afternoon and evening) and is triggering auroras (briefly) as far south as Cape Cod in Florida. Keep your eyes out….
By Jo Nova
Two X-class flares in two days, X7.1 and now X9
I put in an order for an x class flare while I’m away from city lights. I was delighted when a big X7.1 was launched on cue a couple of days ago. It was the second biggest flare this cycle until a few minutes ago when a huge X9.05 occurred. This is now the largest solar flare in Cycle 25, bigger than the flare in May this year which caused all the auroras around the world this year in places like Florida and southern Queensland. That was an X8.7.
The X7.1 flare may bring auroras Friday or Saturday which was exciting enough. The scale is logarithmic, so this latest one is effectively 100 times larger.
Few details are available yet on the latest flare. The same sunspot (AR 3842) caused both x-class flares this week, and it is near the centre of the side facing us.
It does appear to be Earth directed, but as with all things aurora — we won’t know for sure until it happens (or it doesn’t). Space agencies will make guesses about when these will arrive but they may turn up 8 hours early or late, and the direction of the interplanetary magnetic field needs to be “negative” for good auroras.
People who want to see an aurora are best signing up for an email or SMS notification (EG Glendale App). We won’t know exactly when the best action will be until the charged particles from the Coronal Mass Ejection hit the satellites at the Lagrange point. These sit about a million miles away from Earth. When (if) that happens, aurora-hunters will have only 30 minutes to an hour to get to a dark spot.
And of course, the best laid plans may be wrecked by clouds or dawn.
Woah! What a flare! In addition to the X7 #SolarFlare from earlier this week, the same region on the Sun just produced an X9 flare, the *largest* solar flare we’ve seen since 2017! We await further data to determine if it produced an eruption. #spaceweather #astronomy pic.twitter.com/FVKpamTBTW
— Dr. Ryan French (@RyanJFrench) October 3, 2024
Charged particles can take anywhere from 15 hours to 4 days to arrive at Earth. Here’s hoping…
RESOURCES
- Check the Glendale App –sign up, and read the useful help pop-ups.
- National Oceanic and Atmospheric Administration’s Space Weather Prediction Center (SWPC)
- Sign up for email alerts from the Australian Space Weather Forecasting Centre for aurora
- Check data at SpaceWeatherLive or sign up for alerts at SpaceWeatherLive.
- Some bright spark set up Aurorasaurus to track aurora related tweets. Apparently they correlate quite well with geomagnetic indices. If only people were tweeting 150 years ago.
- The image from Nullschool is fast but only loosely indicative on a 3 hourly guesstimate not a minute-by-minute thing (and it usually underestimates the odds).
UPDATE: The AuroraGuy has a good description here.
Find a place with a dark sky to watch from. He suggests the Bortle Scale 1-5 which are country or rural sites. The darkest sites are class 1 and the brightest city is class 9.