Solar cycle
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The Solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a periodic 11-year change in the Sun's activity measured in terms of variations in the number of o
Samuel Heinrich Schwabe (1789–1875), German astronomer, discovered the solar cycle through extended observations of sunspots.
Rudolf Wolf (1816–1893), Swiss astronomer, carried out historical reconstruction of solar activity back to the 17th century.
A drawing of a sunspot in the Chronicles of John of Worcester, c. 1100
An overview of three solar cycles shows the relationship between the solar cycle, galactic cosmic rays, and the state of Earth's near-space environment.
Sunspot
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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
Solar cycle
…cycle, sunspot cycle, or Schwabe cycle, is a periodic 11-year change in the Sun's activity measured in terms of variations in the number of observed sunspots on the Sun's surface. Over the period of a solar cycle, levels of solar radiation and ejection of solar material, the number and size of sunspots, solar…
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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