Well, no, it really isn’t falling.  But parts of it are closer than usual.  Scientists with the U.S. Air Force have found via the C/NOFS (Communication/Navigation Outage Forecasting System) satellite that the ionosphere is currently about 200km lower than would normally be expected.

So what’s the cause?  Global warming (anyone seen the Goracle lately?)?  Climate change?  (A convenient catch-all if there ever was one.)

Nope.  Just simple old solar activity (or lack thereof):

During the night it has been detected at about 420km, rising to 800km during the day. Scientists here at the American Geophysical Union meeting said more typical values would be 640km during night-time and about 960km during the day.

To some extent, this should not be too surprising. The ionosphere reacts to the Sun’s 11-year cycle of activity and our star is currently in a very quiet phase.

“We are in the depths of a very low solar minimum right now and as a result the ionosphere is lower and less dense than, we believe, at any other time in the history of the space age when measurements have been made,” said Dr Hunton.

Nothing earth-shattering.  I just wanted to be able to use the phrase “The sky is falling” in a post.