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Article: An unexpected solar effect on Venus.
- Article from:
- Science News
- Article date:
- May 26, 1990
CopyrightCOPYRIGHT 1990 Science Service, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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An unexpected solar effect on Venus
Pioneer Venus, a spacecraft that has orbited Venus for more than 11 years, revealed early in its mission that the number of free electrons in the planet's ionosphere often varies from one orbit to the next. The reason for this phenomenon, however, appears different from what scientists have assumed.
According to Larry H. Brace of NASA's Goddard Space Flight Center in Greenbelt, Md., two kinds of solar variations may affect the number of electrons in Venus' ionosphere: the sun's extreme ultraviolet (EUV) brightness, and the speed and density of the solar wind. Many researchers working on the problem have assumed that the ...