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Explanation: Why are the regions above sunspots so hot? Sunspots themselves are a bit cooler than the surrounding solar surface because the magnetic fields that create them reduce convective heating. It is therefore unusual that regions overhead -- even much higher up in the Sun's corona -- can be hundreds of times hotter. To help find the cause, NASA directed the Earth-orbiting Nuclear Spectroscopic Telescope Array (NuSTAR) satellite to point its very sensitive X-ray telescope at the Sun. Featured above is the Sun in ultraviolet light, shown in a red hue as taken by the orbiting Solar Dynamics Observatory (SDO). Superimposed in false-colored green and blue is emission above sunspots detected by NuSTAR in different bands of high-energy X-rays, highlighting regions of extremely high temperature. Clues about the Sun's atmospheric heating mechanisms may not only come from this initial image, but future NuSTAR images aimed at finding hypothesized nanoflares, brief bursts of energy that may drive the unusual heating.
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: Sun - X-ray
Publications with words: Sun - X-ray
See also:
- APOD: 2024 September 2 Á A Triangular Prominence Hovers Over the Sun
- APOD: 2024 August 18 Á A Solar Prominence Eruption from SDO
- APOD: 2024 August 4 Á Gaia: Here Comes the Sun
- APOD: 2024 July 28 Á Sun Dance
- Prominences and Filaments on the Active Sun
- APOD: 2024 May 28 Á Solar X Flare as Famous Active Region Returns
- APOD: 2024 May 26 Á A Solar Filament Erupts