According to NASA observations from instruments on board a US Airforce satellite the environment has gotten so bad the sky is falling in – literally.
The Earth’s Ionosphere plasma, where electrons and ions, like Earth and Space, can meet but not touch, at night is typically 640km from the planet.
Now NASA scientists have measured it at night just 420km away from the Earth’s surface – that’s 220km closer! During the daylight hours the distance was 800km compared to the usual 960km.
The result: the nothingness of space is now 17% – 34% closer to the Earth’s surface.
According to Science Daily, these measurements were taken on 16 April, 2008 with the Coupled Ion Neutral Dynamics Investigation unit on the US Airforce’s Communication/Navigation Outage Forecast satellite.
The Ionosphere
The Ionosphere is a veil of sub-atomic and atomic debris that can extend upwards for hundreds of kilometres at the highest part of the Earth’s atmosphere. Scientist already know the amount of this plasma increases with increased short-wave solar energy.
So what has happened is an effect of less incoming radiation (from the sun). Electrons that are usually knocked off in the collisions between photons and atoms, and fly about until they are mopped up by positive ions, are getting dislodged in far fewer numbers.
Thus a measurable contraction in the height of the Ionosphere.
Solar radiation
The Ionisation of the thermosphere ramps up during the day when more ultra-violet sunlight hits the Earth and it winds down at night, and over polar winter time, when there is an absence of sunlight.
The low height of the current Ionosphere also is affected by our Sun’s output of solar radiation, which can vary on an 11 year cycle.
Although this sunspot cycle may not aways correlate with Total Magnetic Index (TMI), currently there are few sunspots and low a TMI: this means much less bazookering the Earth’s upper atmopshere and a much thinner Ionosphere.
Good news?
Without so much proton bombardment, the reduced ionisation means fewer free electrons are produced that can rove about vandalising communications signals.
An important consequence of this is that man-made transmissions, such as radiowaves, radar and GPS should suffer less interference.
This could be good or bad news. A radio listener in England on an analogue radio typically finds channels become alive at night with sounds of foreign channels. Sometimes this is a nuisence, and sometimes interesting (especially for a kid in pre-Internet days to hear radio from as far away as America).
The scientists certainly interpret this situation as good news. They would like to know what exactly caused the drop to be so considerable compared to their expectations?
Further discoveries by the University of Dallas, Texas, made instrument should help.
Science Daily calls the present Sun – Atmosphere situation "an unparalleled opportunity to study the connection between the interior dynamics of the Sun and the response of the Earth’s space environment".