NASA is closely monitoring a major event in our atmosphere. In the upper arcs of our atmosphere, a rarefied layer of gas called “the thermosphere” has partially collapsed and now is rebounding again.

“This is the biggest contraction of the thermosphere in at least 43 years,” says John Emmert of the Naval Research Lab. “It’s a Space Age record. Something is going on that we do not understand.”

This collapse occurred during a period of low solar activity, called a solar minimum, when sunspots and solar flare activity heavily diminish. The thermosphere does many cool things, including intercepting extreme ultraviolet light (EUV) before it hits the Earth’s surface.