Atlas

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Atlas is an inner shepherd moon of Saturn discovered by Richard Terrile in 1980 from Voyager 
photos and was designated S/1980 S 28. In 1983 it was officially named after Atlas of Greek mythology, because it "holds the rings on its shoulders" like the Titan Atlas held the sky up above the Earth. I
t is also designated Saturn XV. 
Atlas is the closest satellite to the sharp outer edge of the A ring, and was long thought to be a shepherd satellite for this ring. However, now it is known that the outer edge of the ring is instead maintained by a 7:6 orbital resonance with the larger but more distant moons Janus and Epimetheus. In 2004 a faint, thin ring, temporarily designated R/2004 S 1, was discovered in the Atlantean orbit.
High-resolution images taken in June 2005 by Cassini revealed Atlas to have a roughly spherical centre surrounded by a large, smooth equatorial ridge similar to Pan or Daphnis. The most likely explanation for this unusual and prominent structure is that ring material swept up by the moon accumulates on the moon, with a strong preference for the equator due to the ring's thinness. In fact, the size of the equatorial ridge is comparable with the expected Roche lobe of the moon. This would mean that for any additional particles impacting the equator, the centrifugal force will nearly overcome Atlas's tiny gravity, and they will probably be lost.
== Gallery ==
File:F Ring and Atlas PIA10448.jpg|Pan with the A and F Rings
File:Cassini Atlas N00084634 CL.png|Atlas from its south pole.
Category:Moons
Category:Shepherd Moon
Category:Inner Moon of Saturn
Category:Objects with Equatorial Ridges
Category:Objects with No Atmosphere
Category:Objects Not in Hydrostatic Equilibrium
Category:Prograde Satellite
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Category:Numbered Objects
Category:Numbered Moons
Category:Outer Solar System Object
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