Air is everywhere. We breathe
it and it surrounds us. For most of human existence air
has been thought to be infinite. In the early 1960s photographs
made by satellites and astronauts confirmed the modern view
that the earth's atmosphere is finite. We live in
an ocean of air extending upward perhaps 1,000 miles. A
thin, narrow band of air, from 5 to 11 miles thick, lies
next to the earth and is the region of continuous winds.
Were it not for wind the component gases of our air would
separate into layers.
Air is highly compressible.
The first three-and-one-half miles of earth's atmosphere
comprise one-half of earth's air by weight. Within this
nearby blanket of heavy air most of earth's weather changes
Technology is the tool which has allowed
us to understand air and weather and the human-caused impacts
on both. Technology has provided insight into how contaminated
air adversely affects our health. Technology has given
us the means to pollute the air and the means to control
and to limit contamination of the air.
Air currents can be a source
of enjoyment, too. The area near Petersburg is highly regarded
nationally for its "Petersburg Wave," which
is a glider pilot's thrill and delight. A prevailing westerly
wind whips across the 4,000- foot plateau which encompasses
Dolly Sods and Roaring Plains. As the wind reaches the eastern
rim of the plateau, it plummets down the steep Allegheny
Front into a broad valley. Once at the bottom, the air shoots
upward in a wave powerful enough to elevate gliders as high
as 26,000 feet.
Last updated on Monday, March 26, 2001