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Sunspot number is correlated with the intensity of solar radiation over the period since 1979, when satellite measurements became available. The variation caused by the sunspot cycle to solar output is on the order of 0.1% of the solar constant (a peak-to-trough range of 1.3 W·m −2 compared with 1366 W·m −2 for the average solar constant).
Mercury is visible as a black dot below and to the left of the center. The dark area above the center of the solar disk is a sunspot. The antumbra (from the Latin ante "before" and umbra "shadow") is the region from which the occluding body appears entirely within the disc of the light source.
The monthly mean sunspot number in the northern solar hemisphere peaked in November 2011, while the southern hemisphere appears to have peaked in February 2014, reaching a peak monthly mean of 102. Subsequent months declined to around 70 (June 2014). [54] In October 2014, sunspot AR 12192 became the largest observed since 1990. [55]
A solar flare is an intense burst of radiation near a sunspot that releases magnetic energy out into space, according to NASA. These giant explosions from the sun send energy, light, and particles ...
Sunspot activity has been measured using the Wolf number for about 300 years. This index (also known as the Zürich number) uses both the number of sunspots and the number of sunspot groups to compensate for measurement variations. A 2003 study found that sunspots had been more frequent since the 1940s than in the previous 1150 years. [30]
Solar cycles are nearly periodic 11-year changes in the Sun's activity that are based on the number of sunspots present on the Sun's surface. The first solar cycle conventionally is said to have started in 1755. The source data are the revised International Sunspot Numbers (ISN v2.0), as available at SILSO. [1]
A sunspot this large is easy enough to see from Earth; all that is needed is a solar filter or pair of eclipse glasses to protect your eyes from the sun's dangerous rays. Sunspot AR3664 compared ...
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 average of 600 km. [1] Sunspots result from the blockage of convective heat transport by intense magnetic fields. Sunspots are cooler than the ...