Did You Know the Earth's Upper Atmosphere Contracted and Collapsed?

Did you know that the atmosphere of the earth contracted and collapsed this week?

Did you know it is not the first time this has happened?

An upper layer of Earth's atmosphere recently collapsed in an unexpectedly large contraction, the sheer size of which has scientists scratching their heads, NASA announced Thursday.

The layer of gas – called the thermosphere – is now rebounding again. This type of collapse is not rare, but its magnitude shocked scientists.

"This is the biggest contraction of the thermosphere in at least 43 years," said John Emmert of the Naval Research Lab, lead author of a paper announcing the finding in the June 19 issue of the journal Geophysical Research Letters. "It's a Space Age record."

The thermosphere interacts strongly with the sun, so is very affected by periods of high or low solar activity. This layer intercepts extreme ultraviolet light (EUV) from the sun before it can reach the ground.

When solar activity is high, solar EUV warms the thermosphere, causing it to puff up like a marshmallow held over a camp fire. When solar activity is low, the opposite occurs.