Last weekend,  May 18th, 2013 an aurora appeared over Marquette, Michigan in the northern USA, after coronal mass ejections from the sun made contact with Earth’s magnetic fields, funneling energy and particles into near-Earth space.

The outer solar atmosphere, the corona, is structured by strong magnetic fields and where those fields are closed, often above sunspot groups, the confined solar atmosphere can suddenly and violently release bubbles of gas and magnetic fields. We call those coronal mass ejections and they erupt from the sun with billions of tons of solar material that can impact satellites. 

This matter that can be accelerated to several million miles per hour in a spectacular explosion. Solar material streams out through the interplanetary medium, impacting any planet or spacecraft in its path.

A pair of a pair of CMEs reached us last weekend and the impacts rattled Earth's magnetic field and sparked Northern Lights visible in the continental United States as far south as Colorado.

Image Courtesy of Amy Cherrette. Link: NASA