A powerful X2.8 solar flare erupted from the sun on Thursday afternoon, the strongest such eruption in over six years. The flare caused radio blackouts in South America and may also spark auroras as far south as New York and Idaho in the next couple of days, forecasters said.
Spaceweather.com called it the most powerful sunstorm since September 2017, while the Space Weather Prediction Center termed it "one of the largest solar radio events ever recorded."
Solar flares are intense bursts of radiation released by magnetic activity on the sun. They can impact radio signals, power grids and navigation systems and endanger astronauts. The X-classification denotes the most extreme flares, with the number providing more specifics on its potency.
This event also released a coronal mass ejection - a massive solar plasma and magnetic field cloud - that may reach Earth. Such clouds can provoke geomagnetic storms when they interact with our planet's field, spawning colorful northern lights displays.
The Space Weather Prediction Center has issued a G2 or "moderate" geomagnetic storm watch for December 17-18, meaning auroras may dip as far south as New York and Idaho.
The Epicenter of the Eruption
This startling solar outburst originated from a blooming sunspot labeled AR3197. Sunspots are temporary dark patches on the sun arising from localized magnetic fields that obstruct hot solar plasma from below.
They often trigger flares and coronal mass ejections. AR3197 produced multiple mid-level solar flares over the past week before unleashing Thursday's monster eruption.
The flare erupted at 5:57 pm EST, heating plasma to tens of millions of degrees and accelerating electrons, protons and heavy ions to near the speed of light. It also spawned a radio burst, causing shortwave radio blackouts across South America.
Flares contain abundant X-rays and sometimes higher energy gamma rays, too. If aimed at Earth, this radiation can disturb the ionosphere and impair HF radio transmissions used in aviation and shipping.
Thursday’s event qualifies as the first X-class flare of Solar Cycle 25, which began in December 2019 after an unusually quiet solar minimum. It also ranks among the strongest in years, overshadowed only by the bevvy of X-flares during the last solar cycle's peak.
Its intensity caught space weather forecasters off guard.
A panel predicted in 2019 that Solar Cycle 25 would be fairly tame, with a subdued peak from 2023-2026. But activity has ramped up surprisingly fast, and the prediction centre recently upped their forecast, now calling for the cycle to peak strongly between January and October 2024.