Explanation:
What's causing unusual jagged shadows on Saturn's rings?
No one is yet sure.
As Saturn nears
equinox,
its rings increasingly show only their
thin edge to the Earth and Sun.
As a result, Saturn's moons now commonly
cast long
shadows onto the
rings.
An example of this is the elongated vertical shadow of
Mimas seen on the above right.
The series of
shorter, jagged shadows that run diagonally, however, are more unusual.
Now Saturn's rings have been known to be made of particles for
hundreds of years,
but these particles have so far escaped direct imaging.
It is therefore particularly exciting that a
preliminary hypothesis holds that these
jagged shadows are
silhouettes of
transient groups of ring particles
temporarily held close by their own gravity.
Future work will surely continue, as the robotic
Cassini spacecraft orbiting Saturn that took the above image will continue to photograph
Saturn's magnificent rings
right through
Saturn's equinox this August.
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