GRAND RAPIDS, Mich. (WOOD) — It’s been an active year for solar storms with northern lights dancing frequently across our nation’s skies.

West Michigan has experienced several northern lights events since May. But what actually causes the northern lights to spark, and how long does it take for the Sun’s energy to reach Earth?

The sun is constantly churning and chugging away, converting hydrogen into helium through nuclear fusion. This process is what produces solar energy. Occasionally, these reactions can get wild. A burst of light and X-ray energy seen on the surface of the sun is known as a solar flare.

The sun is 93 million miles away from Earth. When a solar flare happens, it can be seen by scientists on Earth just eight minutes after it happens.

Sometimes, a solar flare and a coronal mass ejection (or CME) happen at the same time. A CME is an eruption of plasma and particles out into space.

These bursts of energy, or CMEs, traveling through space create a solar wind. When that solar wind slams into Earth, it interacts with Earth’s magnetic field. The bigger the impact, the stronger the “geomagnetic storm.” The reason it is called a geomagnetic storm is because the plasma and particles in the solar wind interact with Earth’s magnetic field on impact. This disruption of Earth’s magnetic field is what causes the northern lights.

The sun is currently in an active cycle, where solar flares and CMEs facing Earth are far more likely. This active cycle is why the northern lights have been so prevalent lately. The sun experiences a cycle of about 11 years of active solar flares followed by 11 years of very low flare activity. This year is expected to be the peak of the 11-year active phase of the solar cycle.