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July 12, 2016

The Sun sometimes pops off in dramatic fashion. It produces explosions known as solar flares — geysers of energy that can equal billions of one-megaton hydrogen bombs.

Our star may also pop off in less-dramatic fashion — the equivalent of only a few hundred H-bombs. But what these little blasts lack in power, they make up for in frequency — there could be thousands of them every second.

These “little” blasts are known as nanoflares. Astronomers first saw hints of their existence in the 1970s. But the first solid evidence for them came a couple of years ago, from two space telescopes.

Theory says the flares occur in the Sun’s outer atmosphere, known as the corona. The corona is millions of degrees hotter than the Sun, and nanoflares could generate the extra heat.

The Sun’s magnetic field frequently forms loops that extend far above the Sun’s visible surface. The surface itself is turbulent, so the loops wiggle around. That causes the lines of magnetic force to overlap. When they do, that may cause a short circuit — a nanoflare.

No one has seen nanoflares directly — perhaps because they don’t really exist, or perhaps because they’re too small and faint to spot against the Sun’s brilliant surface. But observations by ultraviolet and X-ray telescopes have provided hints that the flares are there.

Follow-up observations in the next year or two are planned to find out if the corona really does crackle with the constant explosions of nanoflares

Script by Damond Benningfield

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