Cassini Finds Clumps in Saturn’s Rings
Jet Propulsion Lab — Scientists have only a rough idea of the lifetime of clumps in Saturn’s rings – a mystery that Cassini may help answer.
The latest images taken by the Cassini-Huygens spacecraft show clumps seemingly embedded within Saturn’s narrow, outermost F ring. The narrow angle camera took the images on Feb. 23, 2004, from a distance of 62.9 million kilometers (39 million miles).
The two images taken nearly two hours apart show these clumps as they revolve about the planet. The small dot at center right in the second image is one of Saturn’s small moons, Janus, which is 181 kilometers, (112 miles) across.
Like all particles in Saturn’s ring system, these clump features orbit the planet in the same direction in which the planet rotates. This direction is clockwise as seen from Cassini’s southern vantage point below the ring plane.
Two clumps in particular, one of them extended, is visible in the upper part of the F ring in the image on the left, and in the lower part of the ring in the image on the right. Other knot-like irregularities in the ring’s brightness are visible in the image on the right.
The core of the F ring is about 50 kilometers (31miles) wide, and from Cassini’s current distance, is not fully visible.
The imaging team enhanced the contrast of the images and magnified them to aid visibility of the F ring and the clump features.
The camera took the images with the green filter, which is centered at 568 nanometers. The image scale is 377 kilometers (234 miles) per pixel.
NASA’s two Voyager spacecraft that flew past Saturn in 1980 and 1981 were the first to see these clumps. The Voyager data suggest that the clumps change very little and can be tracked as they orbit for 30 days or more.
No clump survived from the time of the first Voyager flyby to the Voyager 2 flyby nine months later. Scientists are not certain of the cause of these features. Among the theories proposed are meteoroid bombardments and inter-particle collisions in the F ring.
About the Cassini Mission
Launched from Kennedy Space Center on Oct. 15, 1997, the Cassini-Huygens spacecraft will reach the Saturnian region in July 2004.
The mission is composed of two elements: The Cassini orbiter that will orbit Saturn and its moons for four years, and the Huygens probe that will dive into the murky atmosphere of Titan and land on its surface.
The sophisticated instruments onboard these spacecraft will provide scientists with vital data to help understand this mysterious, vast region.
Cassini-Huygens is an international collaboration between three space agencies. Seventeen nations contributed to building the spacecraft. The Cassini orbiter was built and managed by NASA’s Jet Propulsion Laboratory.
The Huygens probe was built by the European Space Agency. The Italian Space agency provided Cassini’s high-gain communication antenna. More than 200 scientists worldwide will study the data collected.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.
The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colo.
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