Monster Sunspot Sends Huge Solar Flare Barrelling Toward Earth

A monster sunspot region around four times larger than the size of Earth has shot a 10 million-degree Celsius (18 million-degree Fahrenheit) solar flare at our planet.

The sunspot region, known as AR3098, has simmered on the surface of the sun for about five days. In that time it's become increasingly active, with solar scientists predicting a high chance of flares.

In the late hours of September 12, that's exactly what happened.

Sunspots are regions of the sun where magnetic fields are particularly intense—so much so that some heat from the sun's interior is prevented from reaching the surface. This makes sunspots appear darker and cooler than surrounding regions.

The sun
A NASA Solar Dynamics Observatory (SDO) image of the sun taken on September 13, 2022. Regions of intense magnetic fields on the sun, known as sunspots, can release explosions of energy such as solar flares into space. NASA/SDO/AIA

When the magnetic fields associated with sunspots suddenly shift or realign, huge amounts of energy can be released. This energy explodes from the sun in the form of a flash of radiation called a solar flare or a cloud of plasma known as a coronal mass ejection (CME).

These expulsions of solar material and energy can interact with Earth's atmosphere and magnetic field, and this can have disruptive effects on modern technologies such as radio communications, navigation systems and even power grids.

Not all flares are equally strong. Flares are classified as A-class, B-class, C-class, M-class, or X-class depending on their strength, with X-class being the strongest and A-class the weakest. Generally, only M- or X-class flares are strong enough to prompt scientists to issue space weather alerts.

As of September 12, AR3098 had a 70 percent chance of releasing a C-class flare, a 20 percent chance of releasing an M-class flare and a 5 percent chance of releasing an X-class flare, according to solar activity news website SpaceWeatherLive.com.

Later that day, it appears that an M-class flare did occur. Solar scientist Alex Young tweeted: "FINALLY! AR3098 just released an M1.7 flare at the end of the day on Sept. 12 UTC. A nice impulsive event seen in SDO 131 showing plasma greater than 10 million Kelvin [10 million Celsius]. Hot hot!"

Young said temporary disruptive effects from the flare occurred over the Pacific Ocean. M1.7 refers to the strength of the flare within the M classification, with 1 being the lowest and 9 the highest.

This observed flare coincided with a two-minute long radio burst reported by the National Oceanic and Atmospheric Administration's (NOAA) Space Weather Prediction Center (SWPC) at 11:43 p.m. UTC (7:43 p.m. ET).

The SWPC said the radio burst was indicative of a solar flare and although it was short-lived it could have caused interference with sensitive radar, GPS and satellite communications equipment. For most people around the world, the flare wouldn't have been noticeable.

Meanwhile, another active sunspot region called AR3088 has recently rotated back into sight of Earth after producing an enormous flare on September 5 that one scientist said would be studied "for years." However, it occurred when the sunspot was facing away from Earth on the sun's far side.