Space is closer to Earth than believedJanuary 8th, 2009 - 1:40 pm ICT by ANI
Washington, Jan 8 (ANI): Space is not as far from the Earths surface as people think, for scientist have discovered that the ionosphere, the layer of electrically charged particles that comprises the outer atmosphere, is thinner than expected, and cooler too.
Knowledge of the shape and size of the ionosphere may help in determining how particularly dense regions within it may distort radio, radar and navigation signals, which can make communications and satellite-based systems less reliable.
“In order to predict how severe those distortions will be, it’’s necessary to know how big those structures in the ionosphere are and where they exist,” Discovery News quoted Roderick Heelis, with the Space Sciences Center at the University of Texas in Dallas, as saying.
The researchers used a suite of NASA instruments called CINDI, which fly on the U.S. Air Force Communication/Navigation Outage Forecast System (C/NOFS) satellite between 250 miles and 530 miles around the equator.
CINDI is an acronym for Coupled Ion Neutral Dynamics Investigation, and works by separately measuring ionized and neutral particles at altitudes where the Air Force satellite flies.
During the summer of 2008, a time when the solar activity was unusually quiescent, the researchers found that the ionosphere was quite thin at those altitudes.
“It was a real fortuitous combination of low solar activity and the satellite’’s [range]. We didn”t expect to be able to look at the top of the ionosphere in all places,” said Hellis.
Based on previous research, computer models had predicted the ionosphere to be about 370 miles above Earth at night and about 620 miles up during the day, which varied due to temperature and other factors.
However, using CINDI, the researchers found that the transition between the ionosphere and space was about 250 miles above Earth at night and about 500 miles up during the day.
The ionosphere is primarily caused by extreme ultraviolet energy from the sun.
The findings were presented at the annual American Geophysical Union conference in San Francisco last month. (ANI)
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