NASA detects strongest solar flare in more than a decade

A pair of solar flares, including the most powerful one in more than a decade, were detected by  NASA’s Solar Dynamics Observatory sun-monitoring probe early Wednesday morning, experts at the US space agency confirmed in an announcement released later on in the day.

The first of the two flares was classified as an X2.2 flare and peaked at 5:10 am EDT, while the second was a larger X9.3 flare that peaked at 8:02 am EDT, NASA reported. X-class flares, they noted, are the most intense, while the number reveals more information about their strength.

“An X2 is twice as intense as an X1, an X3 is three times as intense, etc,” the agency explained. The X9.3 flare was the strongest observed since an X9.0 in December 2006 and the eighth most powerful since at least June 1996, according to and

Both of the flares erupted from AR 2673, an active region on the sun which was also responsible for producing a mid-level solar flare on Monday, NASA said. They added that the X9.3 flare was the largest produced thus far during the current solar cycle, an 11 year period of the sun’s waxing and waning activity that began back in December 2008.

Event caused radio blackouts, but should not affect hurricane monitoring and the NOAA Space Weather Prediction Center (SWPC) reported that the second, more powerful of the flares resulted in high-frequency radio blackouts over a “wide area,” and that those blackouts caused “loss of contact for up to an hour” over the planet’s sunlit side. Low frequency communication, including that used for navigation, was also affected.

Unfortunately, the solar flares come at a bit of an inopportune time for those of us on Earth (and especially in the US), as many are relying on weather satellites to continue monitoring Hurricane Irma and other Atlantic-based storms. Fortunately, experts do not foresee any disruptions.

“The satellites are designed very specifically to take into account these kinds of events,” SWPC physicist Terry Onsager told LiveScience. While some older satellites could be hampered when hit with charged particles and strong magnetic fields from the sun, the probe which is providing images of Irma – GOES-16 – is new, having just been launched last November, he noted.

The size of the second flare is somewhat usual, according to, since the sun is currently at solar minimum, or the period of lowest activity during its 11-year cycle. However, as Onsager told LiveScience, this status is based more on the frequency of flares, not their potential intensity. “We can have large space weather events at any time during the solar cycle,” he said.

For the record, the largest flare ever recorded – at least, dating back to June 1996 – was an X28.0 that occurred on November 4, 2003, according to It was one of only two flares known to have been categorized at least X20.0, with the other coming in April 2001.\


Image credit: NASA