Strongest geomagnetic storm in more than 20 years unleashes stunning Aurora

Historical geomagnetic storm annotated

Satellite image of the Northern Lights captured on May 11, 2024 by the Visible Infrared Imaging Radiometer Suite) at Suomi NPP.

Space scientists and sky watchers were treated to a stunning display of the Northern Lights.

The strongest geomagnetic storm in more than 20 years occurred in May 2024, resulting in stunning global displays of the Aurora Borealis. These events, recorded by satellite and ground photographers, have provided crucial data for scientific research and have marked a significant period of increasing solar activity.

In May 2024, the strongest geomagnetic storm in more than two decades blinded scientists and sky watchers alike. The G5 storm culminated in a remarkable display of the Northern Lights on the night of May 10-11, visible from many areas around the world, including latitudes where auroral sightings are uncommon.

The VIIRS (Visible Infrared Imaging Radiometer Suite) on the Suomi NPP satellite acquired this image of the aurora at 3:20 a.m. Central Time (8:20 Universal Time) on May 11, 2024. The VIIRS day-night band detects nighttime light in a range of wavelengths from green to near-infrared and uses filter techniques to detect signals such as city lights, reflected moonlight and auroras.

> See photos: Stunning Aurora lights up the night during epic geomagnetic storm

In this view, the Northern Lights appear as a bright white band over parts of Montana, Wyoming, the Dakotas, Minnesota, Wisconsin, Iowa and Michigan. But aurora are dynamic, and at other times of the night different opacities and light patterns would have been visible. And although this satellite data appears in grayscale, viewers on the ground saw colors from green (the most common) to purple and red. Atmospheric compounds found at different altitudes influence the color of an aurora.

Aurora near Saskatoon in Saskatchewan, Canada

Photo obtained on May 11, 2024, near Saskatoon, Saskatchewan, Canada. Credit: Gunjan Sinha

Photographers and aurora hunters captured the striking color range in photos from the ground, some of which they shared NASA‘s Aurorasaurus project. The citizen science effort crowdsources eyewitness accounts that scientists can then use to verify or determine the truth of models of where the aurora will be visible from the ground. Auroras occur high in the atmosphere, so observers on the ground may be able to spot them from far away.

Aurorasaurus was launched in 2014 around the time of the last solar maximum – the middle of a roughly eleven-year cycle when the Sun is most active and producing more sunspots, flares and coronal mass ejections. Data collected by citizen scientists was very useful, but the 2014-2015 solar maximum turned out to be relatively “weak,” noted Liz MacDonald, a space scientist at NASA’s Goddard Space Flight Center and leader of Aurorasaurus. When aurora illuminated the sky, most smartphones couldn’t capture it.

Ten years later, the sun’s activity increases again, around the middle of the current solar cycle 25. Photos taken on May 10 and 11 show aurora associated with what NOAA called the most extreme geomagnetic storm since 2003. The image above, taken by Aurorasaurus Ambassador Gunjan Sinha, shows the sky on May 11 looking south from near Saskatoon in Saskatchewan, Canada.

“This event was truly the culmination of our vision for the program,” MacDonald said. “Large storms visible this far south are so rare and we have few opportunities to study them. Photos from citizen scientists can help us with this.”

NASA Earth Observatory image by Wanmei Liang, using VIIRS day-night band data from the Suomi National Polar-orbiting Partnership. Photo by Gunjan Sinha. Story by Kathryn Hansen.

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