Heating the solar corona

The hot outer layer of the sun, the corona, has a temperature of over a million degrees Kelvin, much more than the surface temperature of the Sun which is only about 5500 degrees Kelvin. Moreover, the corona is very active ...

Sunrise II: A second look at the Sun

scillating fibrils, explosive increases in temperature, and the footprints of coronal loops: 13 articles published today provide an overview of the results of the second flight of the balloon-borne solar observatory Sunrise.

Image: Coronal loops over a sunspot group

The Atmospheric Imaging Assembly (AIA) instrument aboard NASA's Solar Dynamics Observatory (SDO) images the solar atmosphere in multiple wavelengths to link changes in the surface to interior changes. Its data includes images ...

Tiny "nanoflares" might heat the Sun's corona

Why is the Sun's million-degree corona, or outermost atmosphere, so much hotter than the Sun's surface? This question has baffled astronomers for decades. Today, a team led by Paola Testa of the Harvard-Smithsonian Center ...

Image: Coronal loops in an active region of the sun

An active region of the sun just rotating into the view of NASA's Solar Dynamics Observatory gives a profile view of coronal loops over about a two-day period, from Feb. 8-10, 2014.

Four cool views of the hot, loopy, spotty sun

A few sunspots are now 'peppering" the surface of our Sun—Spaceweather.com lists about 12 different sunspot groups today. Yesterday (January 7, 2013), astrophotographer John Chumack stepped outside over his lunch break ...

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