You May Have Seen the Northern Lights Over the Weekend, Here’s Why

In the 2006 disaster flick Solar Attack, coronal mass ejections (CMEs) from the Sun act like shotgun blasts, threatening to wipe out all life on Earth. They destroy space probes and crewed spacecraft before punching through the atmosphere and reducing cities to rubble. Eventually, they light the sky on fire, and we have to find a way to put it out before all the air burns up.

These incredible displays of destructive power make good movie fodder, but they overestimate the power of actual CMEs. In the real world, CMEs are chunks of charged plasma from the Sun’s surface, sloughed off during periods of intense electromagnetic activity. When they strike the atmosphere they don’t punch through, they spread out, following along the Earth’s electromagnetic field lines toward the poles. Along the way, they charge atoms in the atmosphere and light up the sky with bright ribbons of color which we call the aurora. If you happened to look up at the night sky over the weekend of May 10 through May 12, 2024, you might have seen an unusual auroral sight, courtesy of a powerful geomagnetic storm.

For More on Solar Weather:
How Solar Explosions Unleash X-Ray Auroras on Mercury
Understanding the Sun’s Solar Cycle and Coronal Mass Ejections (CMEs)
Solar Maximum Will be Earlier, Stronger and Last Longer

Is the Solar Storm Still Happening?

On Thursday, May 9, the National Oceanic and Atmospheric Administration (NOAA) issued a G4 solar storm watch, following a series of solar flares and CMEs coming from sunspot region 3664. Geomagnetic storms are disturbances in Earth’s magnetosphere caused by an exchange of energy with the Sun. They are measured on a 1 - 5 scale, categorized as minor, moderate, strong, severe, or extreme.

G4 conditions were observed Friday night, confirming the earlier NOAA prediction before being upgraded to a G5. It was the first extreme geomagnetic storm since October 2003. NOAA predicted at the time that the storm would continue throughout the weekend. Meanwhile, the Earth was being struck by a series of X-class solar flares. By Sunday, reports of disturbances to power grids, communications systems, and spacecraft operations were filtering in, all of which are expected during periods of severe solar weather.

The excess of solar energy in the atmosphere fed impressive auroral displays visible as far south as Arizona, much farther south than typical. While the Northern and Southern Lights are a common feature of high latitudes, there isn’t usually enough energy to push them very far toward the equator. During a G5 extreme geomagnetic storm, all bets are off.

As of Monday May 13, NOAA has issued a G3 geomagnetic storm warning through the end of the day. Continued geomagnetic activity is possible until sunspot region 3664 rotates out of view, probably by Tuesday May 14. If you didn’t get a chance to catch the show this time around, don’t be too disappointed; this historic storm marks only the beginning of this solar cycle’s solar maximum. We’re likely to see more active sunspot regions, more solar flares, more CMEs, and more geomagnetic storms in the coming months.

In the meantime, catch Solar Attack streaming now on Peacock.