"The sun is entering one of the deepest Solar Minima of the Space Age," wrote Dr Tony Phillips just six weeks ago, on 27 Sep 2018.

Sunspots have been absent for most of 2018 and Earth's upper atmosphere is responding, says Phillips, editor of spaceweather.com.

Data from NASA's TIMED satellite show that the thermosphere (the uppermost layer of air around our planet) is cooling and shrinking, literally decreasing the radius of the atmosphere.