Double Solar Eruptions Spark Widespread Aurora

There aren't enough adjectives to describe last night's endless and profoundly riveting auroral display. And the best part was that so many people got to see it. Two powerful coronal mass ejections (CMEs) launched from the Sun in the wake of X-class flares that came from the large, busy sunspot region 4274. They arrived yesterday evening at Earth's doorstep. Skywatchers reported aurora across the entire U.S. and as far south as the tropics. It was on par with the last most significant storm of the current solar cycle, the Gannon storm that enveloped the Earth for several nights beginning May 10, 2024.

People shared cellphone photos with me from Tennessee, Arkansas, Texas and even Mexico! Here were just a couple reactions:

"Astounding that these colors can be seen with the naked eye! It's gorgeous." — Sherry Phillips of Brimson, Minnesota.
"I finally got my wish here in Tennessee!!" — Michele Knauff Wilson of Tennessee
""It was wilder than any I’ve seen before. Incredibly beautiful." — Richie Townsend of Duluth, Minnesota

The back-to-back mass of particles administered a one-two punch to Earth's magnetic domain, our planet's magnetosphere. Observers sighted auroras as soon as late evening twilight on November 11th, and I can personally testify they raged all night. I made my last image of a towering red pillar near the last-quarter Moon just before 5 a.m. CST.

Great news for all — a third CME from the same sunspot region is expected to fire up another display nearly as fabulous tonight, November 12th. Space-weather forecasters predict a strong storm rated a G3 to punch things up as soon as 6 p.m. CST. Since the Moon rises around midnight, we'll have hours of darkness to relish the sight. The current three-day forecast calls for a more modest (G1 — minor) show on Thursday night, November 13th. A G1 storm is a northern U.S. event primarily visible in the border states. At the G3 level, aurora visibility expands south to the central U.S., and a G4 storm brings the lights well into the southern part of the country.

You know you're likely to see a good show when the magnetic field that's bundled within a CME points in the southern direction — if you're tracking conditions in an aurora app, that quantity is called Bz and a portent of a good show is a large negative number. Southerly fields more easily couple to Earth's north-pointing magnetic field lines. During a typical storm, the Bz might dip to –20 or -25. Not this tempest. At one point, the Bz crashed to –60, a value I've never seen in my life, and a sign of just how profoundly bound Earth and Sun were at that time.

The powerful storm wrapped around our planet's night side, and the field lines stretched to the breaking point. When they snapped like a rubber band, trillions of electrons and protons were flung toward Earth, directly into our upper atmosphere. That interaction caused the donut-like rings that encircle the geomagnetic poles, the auroral ovals, to expand equatorward in both hemispheres, bringing the aurora to millions of observers. Oxygen and nitrogen, stung by the impact of trillions of electrons (and protons), produced a riot of colors. Ordinarily, green is the most common hue visible to the eye in the aurora, but this time red was its equal. Many observers remarked, myself included, how vividly red this display was. The photos show this well.

I hope you saw the wild, savage display of nature last night. If not, you may have another opportunity tonight. For my part, I now have yet another reason to say I'm happy to be alive.