An "X-class" solar flare erupts from the limb of the Sun in this 2014 image. X flares are the most powerful solar flares, which are giant eruptions of radiation and charged particles. Such flares can disrupt spacecraft, knock out power grids on Earth's surface, and cause other problems. Such flares are most common near the peak of the Sun's 11-year magnetic cycle. The next cycle currently is forecast to peak in 2024. [NASA/GSFC/SDO/Wiessinger]
The letter X has a big reputation. It’s used to designate things that are powerful, scary, mysterious, or all of the above. So we have X-rays and X Men, the X Files and X planes, and in the movies, at least a couple of spies designated triple-X.
The Sun gets into the act, too, with X-class solar flares — eruptions that are powerful, scary, and a bit mysterious.
Solar flares are massive explosions. They occur when the lines of the Sun’s magnetic field tangle up, snap, then reconnect. They generate outbursts of particles and radiation that race into the solar system — and they can have dramatic impacts on Earth.
Scientists use five letters to designate the power of a solar flare. From weakest to strongest, they’re A, B, C, M, and X.
The first three categories are fairly mild. Class M flares can have some impact on Earth, but the really nasty ones are the X-class. The largest can produce as much energy as a billion hydrogen bombs.
They’re often accompanied by massive outbursts of charged particles. They can fry orbiting satellites, disrupt radio broadcasts, and knock out power grids. They can force airlines to reroute flights away from the north pole to avoid dangerous levels of radiation. And they can produce displays of the northern lights in places that seldom see them.
The Sun is getting more active these days, building toward the peak of its magnetic cycle in a couple of years — a lot of X-flares in our future.
Script by Damond Benningfield
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