The Nanoflare Hunt
July 8th, 2015, 6:00AMNASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, is usually focused on targets far outside our solar system, but recently astronomers pointed its high-powered X-ray instruments at our sun. This first image, at right, which is combined with more X-ray observations from the Hinode spacecraft and UV images from the Solar Dynamics Observatory, was a bit of a trial run. When the sun’s cycle reaches its minimum in a few years, astronomers hope that NuSTAR will be able to detect nanoflares, which are hypothesized to have about one-billionth the energy of a regular solar flare. If they exist, nanoflares could explain why the sun’s corona is actually much hotter than its surface.