The Sun’s activity cycle lasts approximately 11 years and is driven by the ‘solar dynamo’, the process responsible for generating the Sun’s magnetic field. At the beginning of this cycle, known as the solar minimum, there is minimal activity with few sunspots. As we approach solar maximum, we see an increase in brilliant explosions, dark sunspots, loops of plasma and swirls of super-hot gas.
The most recent solar minimum occurred in December 2019, two months before Solar Orbiter launched. Early views from the spacecraft showed that in February 2021 the Sun was relatively calm. However, recent views taken during a close approach to the Sun in October 2023 show a striking increase in solar activity. This could indicate that the maximum may occur earlier than expected, up to a year before forecasted.
Solar Orbiter is an international collaboration between ESA and NASA, operated by ESA. Its mission is to predict the timing and strength of solar cycles, which is crucial because extreme eruptions can damage ground-based electricity grids and disable orbiting satellites. The Extreme Ultraviolet Imager (EUI) instrument onboard Solar Orbiter reveals the Sun’s upper atmosphere, which has a temperature of around a million degrees Celsius. EUI helps scientists investigate mysterious heating processes that occur in the Sun’s outer regions. Since EUI views the Sun in ultraviolet light, which is invisible to human eyes, a yellow color is added to help us visualize our changing Sun.