In
astrogeology, an arachnoid is a large geological structure resembling a
spider web. They are of unknown origin, and have been found only on the surface of the
planet Venus. They appear as
concentric ovals surrounded by a complex network of
fracture
Fracture is the appearance of a crack or complete separation of an object or material into two or more pieces under the action of stress (mechanics), stress. The fracture of a solid usually occurs due to the development of certain displacemen ...
s, and can span 200 kilometers. Over 90 arachnoids have been identified on Venus.
Arachnoids could be related to
volcano
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most oft ...
s, however it is also possible that different arachnoids are formed by different processes.
[This article contains text from the Astronomy Picture of the Daybr>]
As a work of the United States Federal Government, it is in the public domain. One possible explanation is that an upwelling of magma from the interior of the planet pushed up on the surface, causing cracks. An alternate theory concerning their origin is that they are a precursor to
Corona (planetary geology), coronae formation.
Much of what is known about arachnoids is the result of studies performed by C.B. Dawson and L.S. Crumpler.
See also
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Chaos terrain
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Geysers on Mars
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Pancake dome
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Rille
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Coronae
References
External links
*
''This article incorporates text from a public-domain
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
website.''
Surface features of Venus
Geology of Venus
Planetary geology
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