Cassini discovers atmosphere on Saturn's Enceladus:

20 March 2005 | 14:15 Code : 4823 Geoscience events
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New discoveries by the National Aeronautics and Space Administration's (NASA) Cassini spacecraft has revealed an atmosphere on Saturn's icy moon, Enceladus, Xinhua reports.

New discoveries by the National Aeronautics and Space Administration's (NASA) Cassini spacecraft has revealed an atmosphere on Saturn's icy moon, Enceladus, Xinhua reports.

Scientists had formerly believed that Enceladus, which has a diameter of about 500 km, is too small to exert the gravity required to hold an atmosphere very long.

But with the latest discovery by NASA's Cassini spacecraft that approached within 500 km of the moon's surface in March, scientists are attributing the atmosphere to volcanism, geysers, or possibly gases escaping from the surface or the interior.

In 1981, NASA's Voyager spacecraft flew by Enceladus at a distance of 90,000 km without detecting an atmosphere. But it revealed that the moon was geologically active and was the source for Saturn's icy ring.

It is also possible that the atmosphere detection was beyond Voyager's capabilities or that something may have changed since then, scientists have said.

"These new results from Cassini may be the first evidence of gases originating either from the surface or possibly from the interior of Enceladus," said Michele Dougherty, principal investigator at the Cassini project.

Enceladus is the most reflective object in the solar system, reflecting about 90 percent of the sunlight that hits it.

--Indo-Asian News Service

tags: QAZVIN


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