Solar activity follows an 11-year cycle – here’s how it controls eruptions and solar flares

When you look up at the sky on a sunny day, the Sun might seem like a bright spot, unchanging in the sky. But the Sun is a complex, dynamic celestial body, wrapped in electrical currents and magnetic fields that constantly move and tangle as it rotates. At times the Sun’s surface is very active, casting out powerful bursts of plasma called coronal mass ejections, while at other times it is calmer. I’m a solar physicist who has spent over a decade researching the Sun. Its movement and activity is directly linked to conditions on Earth: Solar flares and ejections can cause space weather that produces beautiful Northern lights but threatens satellites. This activity follows a roughly 11-year-long cycle, and learning about this cycle helps researchers predict future space weather. Inside the Sun The Sun is a star composed of plasma: a hot, ionized gas. The plasma acts as an electrically conductive fluid, and generates large-scale magnetic fields that encircle the Sun. The Sun is composed of several layers, all made up of a plasma that’s about 70% hydrogen and 28% helium by mass. The Sun has a solid core at its center and a dense layer outside the core,…

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