bn:01336207n
Noun Concept
EL
Ηλιακή κηλίδα  ηλιακού κύκλου  κύκλο των ηλιακών κηλίδων
EN
The solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a nearly 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. Wikipedia
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