Largest Known Planetary Ring Discovered
Ron Cowen reports for Science News:
FAJARDO, Puerto Rico — A newly discovered planetary ring can run circles around all the others. The gossamer band of dust encircles Saturn and has a measured diameter of about 24 million kilometers, or 200 times the diameter of the planet.
This finding makes the band the largest known planetary ring in the solar system, researchers reported October 6 at the annual meeting of the American Astronomical Society’s Division for Planetary Sciences. A billion Earths could fit inside the ring.
Calculations indicate the tenuous ring is probably even more extensive and is likely to have a diameter reaching 36 million kilometers.
Too faint to be seen from Earth, the ring extends beyond Saturn’s outer moon Phoebe. Anne Verbiscer and Michael Skrutskie of the University of Virginia in Charlottesville, along with Douglas Hamilton of the University of Maryland in College Park, reported evidence suggesting that the ring is supplied by material that is continually knocked loose from the dark moon’s surface.
