The Sun’s 11-year cycle

This video from the ESA/NASA SOHO (Solar and Heliospheric Observatory) satellite shows the Sun’s 11-year cycle of activity. Astronomers have recently observed a change in the atmosphere of exoplanet HD 189733b, which was observed losing over 1000 tonnes of gas per second. While they believe that a powerful stellar flare is the most likely explanation for the atmospheric evaporation, a longer, slower variation in stellar activity, similar to the 11-year sunspot cycle could also explain this.