Sunspot
Videos
Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit conv
The Swedish 1-m Solar Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands
NASA's SDO Observes Largest Sunspot of the Solar Cycle
Sunspots 1302 Sep 2011 by NASA
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Wilson effect (astronomy)
Videos
In astronomy, the Wilson effect is the perceived depression of a sunspot's umbra, or center, in the Sun's photosphere. The magnitude of the depression for the umbra is between 500 and 1000 km, with an
Wilson's original sketch demonstrating the Wilson effect.