Cassini ends journey with eye catching ring shadow effect on Saturn

New Delhi : NASA's Cassini spacecraft may had ended its journey around Saturn, but before its final plunge into the planet's atmosphere, the spacecraft captured a weird ring shadow effect in Saturn's Ionosphere.

The astronomers revealed about Cassini's journey through Saturn's inosphere, at altitudes between 2,600 and 4,000 kilometres; they said that the spacecraft beemed the shadows cast by the rings block the Sun's ultraviolet radiation, reducing ionisation in those regions.

Effectively, the rings significantly change the gas giant's atmosphere in a way we didn't know about before.

Cassini's data from its 11 orbits reveals a different effect though - a clear difference in the planet's cold, dense ionosphere - a layer in the planet's upper atmosphere between 300 and 5000 kilometres (186 and 3,107 miles) in altitude, ionised by ultraviolet radiation.

Researchers from the Swedish Institute of Space Physics and NASA Goddard have found that there is less ionisation and a noticeable drop in plasma in places where the ring shadows fall.

They concluded that the B-ring and most of the A-ring must be opaque to extreme ultraviolet radiation. Meanwhile, the effect was not observed for the C and D rings, which therefore must allow ultraviolet radiation to pass through.

"I think the jury is out on ring rain," co-author William Kurth of the University of Iowa told Newsweek. "Radio and plasma wave observations - coupled with others - will ultimately shed light on this."