Solar storm

Look: NASA captures X-class solar flare in incredible detail

Originally Published: 

The last week of October 2021 was a busy time for the Sun, as a burst of solar activity culminated in an X-class flare on October 28.

X-class flares are the strongest type of solar flare.

Since the start of the current solar cycle in December 2019, there’s only been one other X-class flare, in July 2021.

October’s flare was an X1 — the weakest kind of X-class flare, but still capable of affecting Earth’s atmosphere.

A solar flare happens when a burst of radiation erupts from the Sun’s surface. They’re often accompanied by the release of plasma, called a coronal mass ejection.


That’s what happened Thursday, October 28. The CME’s plasma triggered a geomagnetic storm when it reached Earth’s magnetic field two days later.

Erik Simonsen/Photodisc/Getty Images

Geomagnetic storms can cause satellites to malfunction and disrupt the power grid, but this one had a more benign effect.

Yelena Vereshchaka/TASS/Getty Images

The disturbance of Earth’s magnetosphere created aurorae as far south as New York City over Halloween weekend.

Cloudy weather hid the light show from most of the U.S., but higher latitudes of Canada and Europe had better luck.

Michael Charnick

The Sun is most active toward the middle of its 11-year cycle, so we could be seeing more frequent solar flares in the next few years.


Most solar flares go largely unnoticed on Earth, but they’re much more dangerous outside of the protection of the magnetosphere.

Heritage Images/Hulton Archive/Getty Images

Astronauts could be at risk of radiation sickness and cancer if they’re caught in a charged solar wind in space.

With a growing number of crewed missions to space planned for the next few years, it’s never been more important that we improve our ability to predict solar flares ASAP.

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