Reading Voyager I's message from Saturn
National Aeronautics and Space Administration (NASA) scientists have been reading letters to home from an interplanetary tourist. The spacecraft Voyager I, launched in 1977, flew past Saturn last fall. By "imaging" the planet -- scanning its surface, rings, and moons with a variety of instruments --Voyager gathered a wealth of raw data and transmitted it to Earth.
Scientists have been pouring over those data since. Yesterday they released highlights of their findings.
The pattern of the planet's beautiful rings is more complex than previously known. Voyager confirmed that the rings are formed from small ringlets, like grooves on a record, and that the ringlets themselves are composed of tiny orbiting particles.
The space probe discovered numerous ringlets in an area previously thought to be a gap -- the Cassini division between the A and B rings. (Rings are lettered according to their date of discovery, not their distance from the planet.) A carefully aimed shot of the imaging equipment also revealed that the rings continue right up to the planet's surface.
And Voyager I detected some rebellion against concentric conformity. an "unexpected discovery" revealed two braided rings twining around each other within the F ring, and some rings had spoke-like lines across them.
Saturn's moon Titan was found to have an interesting atmosphere about it. Scientists have long searched for clues to primeval Earth on Titan, because of atmospheric similarities. Voyager I found nitrogen to be the main element. And Titan's temperature would apparently make methane behave as water behaves on Earth.
"Rivers of methane may cut through glaciers of methane under a nitrogen sky," reads a NASA summary of the project. Perhaps more importantly, it was found that Titan's methane was converted to a number of compounds, including hydrogen cyanide, an element in lifeforming amino acids.
Voyager I spotted two "shephered satellites" on the edges of the F-ring. Scientiests speculate these moons ride herd on orbiting particles, bumping them back into place by transferring energy when they start to wander.
The 10th and 11th of Saturnhs 15 confirmed moons were found to be revolving in the same orbit. their current speeds would dictate a collision in about two years, but scientists say gravitational interaction will probably prevent that from happening. In all, Voyager I spotted three, new moons and confirmed three whose existence had previously been speculated.
Voyager imaging team leader Dr. Bradford Smith said the findings leave unanswered questions, such as why Saturn has such tremendous winds at its center , and why it radiates more than twice the amount of heat it receives from the sun. A more-detailed study will appear in the April 10 issue of Science magazine.
Voyager II, scheduled to fly by Saturn on Aug. 26, 1981, may help answer the questions. The second satellite's itinerary also will provide peaks at Uranus in 1986, and Neptune in 1989. Voyager I, meanwhile, will continue onward at 47, 000 m.p.h. to discover one more important bit of information -- where the solar wind (heliopause) ends, defining the edge of our solar system.