Explanation:
What causes the mysterious spokes in Saturn's rings?
Visible on the left of the
above image
as ghostlike impressions, spokes were first discovered by the
Voyager spacecraft
that buzzed by Saturn in the early 1980s.
Their existence was unexpected, and no genesis hypothesis has ever become accepted.
Oddly, the spokes were conspicuously
absent from initial images sent back by the
robot Cassini spacecraft
now orbiting Saturn.
Analyses of archived
Voyager images have led to the
conclusions that the transient spokes, which may form and dissipate over a few hours, are composed of electrically charged sheets of small dust-sized particles.
Some recent images from Cassini like that
shown above
have now finally shown the enigmatic spokes superposed on
Saturn's B ring.
Hypotheses for spoke creation include small meteors impacting the rings and
electron beams from Saturnian atmospheric
lightning
spraying the rings.
Observations of the puzzling spokes, as well as creative origin speculations, are ongoing.
