Audio Eclipse August 11th May Fill The Sky...08/05/99

(NASA) During a total solar eclipse, day becomes night for a few precious minutes. The temperature drops, birds stop singing, and bees return to their hives for a premature rest. An eerie quiet envelopes the landscape inside the path of totality.

However, from the unique perspective of a ham radio operator, night is anything but quiet - and neither is a solar eclipse. Many shortwave radio stations that are undetectable in daytime are easy to pick up at night. The reason has to do with the Sun's effect on Earth's atmosphere. During the day, solar UV radiation ionizes atoms and molecules in the upper atmosphere, creating a zone called the "ionosphere." The uppermost part of the ionosphere, called the F layer, is so thoroughly ionized that some free electrons exist there - even at night - when the UV source (the Sun) is not present. The F layer is like a mirror for radio waves with frequencies below about 20 MHz. Shortwave transmissions from earth hit the F layer and bounce back down. In fact, many such bounces can occur, and this is the reason why over-the-horizon transmissions are possible at short wave frequencies.

As the Moon's shadow moves across the earth the temperature in the upper atmosphere will drop, changing the wind pattern as air contracts in on the eclipse region. In the absence of UV radiation from the Sun, the ionosphere rapidly begins to decay. The shadow of the moon races through the atmosphere at supersonic speeds, causing wind and waves of electron-ion recombination to spread through the atmosphere from the eclipse region. The effects could be global.

Folks, I think there will be a whole lot more to come. This article is just touching the surface.  MB

Mitch Battros
Producer - Earth Changes TV
http://www.earthchangesTV.com