Northern lights may be visible across parts of the US this weekend. Why are they so active right now?

The intensity and frequency of Northern Lights, also known as Aurora Borealis, are greatly influenced by solar activity. Specifically, they're often more active due to solar storms, also called a Coronal Mass Ejection or CME. These are bursts of gas and magnetic field released from the sun. When the ejected solar particles reach our planet, they interact with Earth’s magnetic field, resulting in wide spread lights as they collide with gases in Earth’s atmosphere. The color of the lights, usually green, but occasionally red, yellow, blue and violet, is determined by the type of gas particles that are colliding. The strength of this phenomenon also depends on the solar cycle, an approximately 11-year cycle of variations in solar activity. Peaks within this cycle can lead to more intense and frequent occurrences of Northern Lights. Therefore, if Northern Lights are predicted to be particularly active over a certain period, it might be the result of a peak in the solar cycle or an unusually strong solar storm.