Updated May 15, 2024 - Science

Sun unleashes largest flare of this solar cycle

A screenshot of a NASA image capturing in blue the strongest solar flare of the sun's cycle

A NASA image capturing the strongest solar flare of the Sun's current cycle. Screenshot: NASA Sun & Space/X

The Sun unleashed the largest flare of its current cycle on Tuesday, days after it generated a powerful solar storm that brought stunning auroras to Northern and Southern Hemisphere skies.

The big picture: "NOT DONE YET!" tweeted NOAA's Space Weather Prediction Center as it issued an alert warning of potential disruptions to radio signals due to the X8.7 flare — the largest since 2017.

Driving the news: The flares were emitted from a super active sunspot cluster, Active Region 3664, which shot out coronal mass ejections (CME) — large bursts of plasma from the Sun.

  • These triggered severe geomagnetic storms directed at Earth, which resulted in the Northern and Southern Lights being visible to much of the world.

Between the lines: The Sun's activity is measured in 11-year cycles and more frequent activity was expected because the current Solar Cycle 25 that began in December 2019 was very close to its peak, per Rob Steenburgh, a space scientist at the SWPC.

  • "It reaches a crescendo at solar maximum and then gradually decays, with activity becoming less frequent," he said in an email last Thursday when NOAA issued a "very rare" Severe (G4) Geomagnetic Storm Watch that forecast possible auroras in the first such alert in 19 years.

Yes, but: The SPC said in its alert that due to the current location of AR3664 "any CME associated with this flare will likely NOT have any geomagnetic impacts on Earth," so auroras are unlikely.

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Editor's note: This article has been updated with more context, further comment from the SWPC on AR3664's location and comment from Rob Steenburgh, a space scientist at the SWPC.

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