Questa immagine potrebbe avere delle imperfezioni perché è storica o di reportage.
Image from the Solar and Heliospheric Observatory (SOHO) spacecraft show sunspots at the current solar minimum (2009). The sunspot images were captured by the Michelson Doppler Imager (MDI) using filtered visible light. On March 18, 2009, the face of the Sun was spotless. On March 18, 2009 our star was relatively subdued. Centuries of observations have shown that the number of sunspots waxes and wanes over a roughly 11-year period. Solar Cycle 24 began in early 2008, but showed minimal activity through early 2009. The small changes in solar irradiance that occur during the solar cycle exert a small influence on Earth's climate, with periods of intense magnetic activity (the solar maximum) producing slightly higher temperatures, and solar minimum periods such as that seen in 2008 and early 2009 likely to have the opposite effect. Periods of intense magnetic activity on the Sun can spawn severe space weather that damages infrastructure in our high-tech society. Roughly a million miles away from our planet, the SOHO spacecraft sits between Earth and the Sun, giving us an unobstructed view of the nearest star.
