Three-Telescope View of the Sun

This composite image of the Sun includes high-energy X-ray data from NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) shown in blue; lower energy X-ray data from the X-ray Telescope (XRT) on the Japanese Aerospace Exploration Agency's Hinode mission shown in green; and ultraviolet light detected by the Atmospheric Imaging Assembly (AIA) on NASA's Solar Dynamics Observatory (SDO) shown in red. NuSTAR's relatively small field of view means it can't see the entire Sun from its position in Earth orbit, so Figure A is a composite of 25 images, which were taken by the observatory in June 2022. NuSTAR sees high-energy X-rays that appear at only a few locations, where the hottest material is present in the Sun's atmopshere. By contrast, Hinode's XRT and SDO's AIA detect detect wavelengths emitted across the entire face of the Sun. The hotspots observed by NuSTAR might be caused by collections of nanoflares, or small outbursts of heat, light, and particles from the Sun's surface that subsequently heat the atmosphere. Individual nanoflares are too faint to directly observe amid the Sun's blazing light.