Are you ready to see the northern lights and comet C/2023 A3 (Tsuchinshan-ATLAS) this weekend?
It’s been a week of intense solar activity and displays of aurora across the world, with several X-class solar flares followed by a G3 or G4 geomagnetic storm in the early hours of Oct. 7 and Oct. 8.
Though not on the scale of May 10’s extreme G5 storm, the result was spectacular aurora seen across the world at lower latitudes than is typical.
There could be more. The sun produced a powerful X1-class solar flare on Oct. 7 and an X1.8-class solar flare early on Oct. 9. NASA’s Solar Dynamics Observatory captured them.
If the northern lights are visible after dark this weekend — something that looks likely for northern-tier U.S. states — they could be spotted soon after a brief post-sunset display from comet C/2023 A3 (Tsuchinshan-ATLAS).
The latter is currently a very bright object lost in the sun’s glare, but is about to emerge. Look to the west immediately after sunset from Thursday onwards.
‘Equinox Effect’
This increased geomagnetic activity, the longer nights in the northern hemisphere and the lingering effects of the “equinox effect” means there’s a higher chance of catching the aurora in the coming weeks.
The solar flares are not particularly significant for those after a glimpse of the northern or southern lights. These extreme ultraviolet flashes of electromagnetic radiation from the sun travel at light speed, so they travel the 93 million miles (150 million kilometers) between the sun and Earth in just eight minutes. They frequently cause brief radio blackouts.
Mass Ejections
It’s what comes in the wake of solar flares that is important. Coronal mass ejections are clouds of charged particles that travel at slower, though inconsistent, speeds, taking a couple of days to reach Earth on the solar wind. These clouds can have tails, lengthening their effects, and speed towards Earth as single events or in swarms.
These CMEs’ impact on Earth’s magnetic field causes the aurora; when charged particles accelerate down the field lines of Earth’s magnetic field, they charge up atoms in the atmosphere and create beautiful displays of green and red light.
Weekend Auroras?
For a CME to have any impact on Earth, it must be heading in Earth’s direction. It looks likely that’s precisely the case for the CME produced on Oct. 9, meaning likely aurora on Friday, Oct. 11 and Saturday, Oct. 12 (though possibly also on Thursday, Oct. 10). Nothing has been confirmed yet. Space weather forecasts change a lot, so keep an eye on my feed and NOAA’s Aurora Dashboard, specifically for its helpful Aurora Viewline for Tonight and Tomorrow.
However, there’s no doubt that right now is the best time to see the aurora at mid-northern and mid-southern latitudes than for 23 years. The sun has a solar cycle lasting about 11 years, with the current Solar Cycle 25 now seeming much more potent than predicted. So much so that NOAA’s Space Weather Prediction Center and NASA announced on Tuesday, Oct. 8, that it will hold a media teleconference at 2 p.m. EDT on Tuesday, Oct. 15, to discuss the sun’s activity and the progression of Solar Cycle 25. Is “solar maximum” already here?
Wishing you clear skies and wide eyes.
