Nanoflares are tiny eruptions on the Sun, one-billionth the size of normal solar flares. Eugene Parker – of Parker Solar Probe fame – first predicted them in 1972 to solve a major puzzle: the coronal heating problem.
That's the mystery of how the Sun’s outer atmosphere, or corona, gets so incredibly hot. Despite being much farther away from the solar core, it's millions of degrees hotter than the layers beneath it.
Nearly 50 years later the coronal heating problem still hasn’t been solved. It has been hard to confirm any of a handful of different theories, in part because no one has ever actually seen a nanoflare.
Read more at: NASA/Goddard Space Flight Center