Printer Friendly

Saturn: ring ripple suggests 19th moon.

Saturn: Ring ripple suggests 19th moon

Clues to an unseen moon have hidden since 1980 in the spiky, weed-like patterns of brightness recorded by Voyager 1 as it flew past Saturn's F-ring. By mathematically parting those weeds, astronomers have found five gentle ripples of ring brightness, each with its own periodicity. One ripple, they say, suggests that an unidentified moon, less than 10 kilometers in diameter, traces an eccentric orbit around the giant planet.

Scientists have long puzzled over irregular density variations in Saturn's F-ring, and have suspected that the gravity of nearby moons plays a role. To explore that possibility, Robert A. Kolvoord and Joseph R. Burns of Cornell University, working with Mark Showalter of Stanford University, indirectly examined the density variations by analyzing the ring's shine. Clumping and spreading of F-ring particles, they reasoned, would increase and decrease the ring's reflectivity.

As expected, the analysis showed one undulation due to Prometheus, the nearest satellite to the ring at a distance of 832 km. However, the smaller and more distant moon called Pandora -- 1,520 km from the ring -- causes no apparent perturbation, they report in the June 21 NATURE.

One of the four remaining ripples hints at the gravitational influence of an elusive moon located 1,180 km from the ring, the researchers say. But a final ruling on the proposed moon -- which would represent the planet's 19th known satellite -- must await the scrutiny of the Cassini orbiter, scheduled to begin its tour of Saturn in 2002.
COPYRIGHT 1990 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1990, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Publication:Science News
Date:Jul 14, 1990
Previous Article:Strong-arming the T. rex forelimb.
Next Article:Mars magnetism: a moot question?

Related Articles
Titan: no global ocean, maybe some seas.
Tar sands on Iapetus.
Figuring out the fragments of Hyperion.
Five-year hunt locates Saturn's 18th moon.
Saturn's 18th moon linked to dusty object.
Hubble: evidence of oceans on Titan?
Voyager through the solar system: a 3-D view of moons and planets.
Saturn ring toss: Hubble finds more moons.
New Saturn moons or only transient debris?
New moons for Saturn.

Terms of use | Privacy policy | Copyright © 2020 Farlex, Inc. | Feedback | For webmasters