A solar flare is a sudden flash of increased brightness on the Sun, usually observed near its surface and in close proximity to a sunspot group. Powerful flares are often, but not always, accompanied by a coronal mass ejection.

How do solar flares affect Earth?

"Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel."

What are solar flares?

A solar flare is burst of radiation from the sun from the release of magnetic energy associated with sunspots, according to NASA. ... The colorful aurora forms when the particles flowing from the sun get caught up in the Earth's magnetic field.