The Sun undergoes a cycle of activity that lasts around 11 years, during which we witness an increase in brilliant explosions, dark sunspots, loops of plasma, and swirls of super-hot gas. This activity is caused by the ‘solar dynamo’, a process that generates the Sun’s magnetic field. At the beginning of this cycle (the solar minimum), there is minimal activity with few sunspots. As it approaches its maximum, activity steadily increases until it decreases again to a minimum.
In December 2019, the most recent solar minimum occurred just two months before Solar Orbiter launched. Early views from the spacecraft showed that in February 2021 the Sun was still relatively calm. However, recent theories suggest that solar maximum could arrive up to a year earlier than expected due to an increase in solar activity observed by Solar Orbiter during its October 2023 close approach to the Sun.
Solar Orbiter is an international collaboration between ESA and NASA and is operated by ESA. Its mission aims to help us predict the timing and strength of solar cycles. This information is vital as extreme eruptions can cause significant damage to ground-based electricity grids and disable orbiting satellites on Earth. The images were taken by Solar Orbiter’s Extreme Ultraviolet Imager (EUI) instrument, which reveals the Sun’s upper atmosphere at temperatures around a million degrees Celsius. EUI helps scientists investigate mysterious heating processes occurring in the outer regions of the Sun. Since EUI views the Sun in ultraviolet light, which is invisible to human eyes, yellow coloring has been added to help us visualize these changes in our changing Sun.
The Solar Dynamo Process:
The ‘solar dynamo’ refers to a complex process within our Sun that generates its magnetic field through convection currents deep within its core.
At the beginning of each cycle (the solar minimum), there is little or no activity with only a few sunspots visible on its surface.
As we approach maximum (the solar maximum), more intense explosions occur with an increase in dark sunspots and loops of plasma.
After reaching its peak, activity slowly decreases again until it returns to another minimum.
This cycle lasts approximately 11 years and provides valuable insights into how our Sun works over time.
In recent years, scientists have used data collected by spacecraft like Solar Orbiter to better understand these cycles and their effects on Earth.
By monitoring these changes closely, we can take steps to mitigate any potential negative impacts on life on Earth such as damage caused by extreme eruptions on ground-based electricity grids or disabled orbiting satellites.