For fun, I titled this post in the negative because the past few times I've shared an optimistic space weather forecast, our hopes have been crushed. Either the aurora didn't show, arrived early or late or simply didn't live up to expectations.. Nature. So frustrating, right? I don't want to lead you on but do want to alert you to the possibility of a minor (G1) storm this evening. If it happens, folks living in the northern U.S. or southern Canada would likely see arcs and perhaps a few rays in the lower half of the northern sky between about 10 p.m. - 1 a.m. Central Time (Oct. 10-11).
A moderately strong M-class flare exploded in the sunspot group 2882 during the wee hours of Oct. 9 and sent a "halo CME" squarely towards the Earth. Judging by the live data-stream from NASA's DSCOVR satellite, located 1 million miles (1.5 million km) ahead of the Earth, the blustery particle winds arrived earlier today as predicted. Cross your fingers they'll continue to rattle the planet's magnetic field into tonight.
Active region 2992 is currently the sole sunspot group on the forward-facing sun. While it possesses only a few spots, its "leader" is several times larger than the Earth and visible — with a little effort — with the naked eye through a safe solar filter. I saw it yesterday as the tiniest of black dots through a #14 welder's glass. The group has been fairly active, so maybe we'll see more flares and aurora changes in the coming week.
If we don't, maybe the Earth itself can help.. New results from NASA's THEMIS-ARTEMIS spacecraft have revealed that the planet can create a type of "diffuse aurora" (see a photo here) all on its own without help from the sun. The aurora looks like a green haze that occasionally exhibit swirls or ripples.. We see it as mush, but the particles that create the soft glow represent 75% of the nightly particle energy input into Earth’s upper atmosphere.
Beams of electrons (red in the video above) spray out of the planet's poles, where they're accelerated by electric fields in the magnetosphere. The beams then converge along the magnetosphere's equator to form Electron Cyclotron Harmonic (ECH) waves (pink). These move earthward and knock electrons (orange) out of orbit, which fall back into the atmosphere and excite the air to glow as diffuse aurora. No help from the sun, thank you!
The brief video was created by E. Masongsong UCLA EPSS, NASA Eyes Audio Credit, Martin O. Archer, Imperial College London, NASA and HARP. Be sure you turn the volume up to hear the cool ECH waves.
"Astro" Bob King is a freelance writer for the Duluth News Tribune. Read more of his work at duluthnewstribune.com/astrobob.