SCIENCE - Saturn's rings shine in new NASA photo - WORLD

 

Stunning ... NASA's Cassini spacecraft's photo of Saturn. Photo: NASA

 

A stunning new image taken by NASA's Cassini spacecraft shows off the southern side of Saturn and the planet's iconic ring system.

The near-infrared photo was taken from 14 degrees under the ringplane, researchers said, and looks toward the unlit side of the planet's rings. Cassini was about 2.9 million kilometres from Saturn, the second-largest planet in the solar system, at the time.

The 504 km-wide Enceladus, one of more than 60 moons that orbit the planet, can also be seen in the image. Despite being covered in ice, many researchers say Enceladus has one of the best chances in the solar system of hosting life beyond Earth, due to a large ocean of water that is thought to sit below the ice. It also generates a large amount of internal heat, thought to power geysers that erupt at the southern polar regions. The geysers were discovered by Cassini in 2005.

The $US3.2 billion Cassini mission launched in 1997 and has been studying Saturn since it arrived at there in 2004. The craft will study the ringed planet until at least 2017, and possibly beyond that.

In 2005, the Huygens lander touched down on Saturn's largest moon, Titan, and relayed the first photos ever from its surface.

Titan is often described as being more like a planet than a moon. It is the only other body in the solar system with a dense, nitrogen-dominated atmosphere aside from Earth. For this reason, some scientists believe that it, too, may be able to support life.

Read more: http://www.smh.com.au/technology/sci-tech/saturns-rings-shine-in-new-nasa-photo-20121002-26w5i.html#ixzz288xD2o4K

SCIENCE - WORLD

Saturn’s largest moon likely has an underground ocean

This undated true color image by the Cassini spacecraft released by Nasa shows Saturn’s largest moon, Titan, passing in front of the planet and its rings. – AP

CAPE CANAVERAL: Nasa’s Cassini spacecraft has found strong evidence for an ocean of water beneath the frozen crust of Saturn’s largest moon Titan, scientists said Thursday.

The finding propels Titan into a short list of places including Jupiter’s moon Europa and Saturn’s smaller moon Enceladus suspected of harboring underground seas.

“The evidence is strong that Titan is squishy,” said planetary scientist Jonathan Lunine, with Cornell University.

The evidence was put together during six passes over Titan by Cassini, which is orbitting Saturn, between 2004 and 2011.

During the flybys, scientists measured minute changes in the pitch of radio signals passing between the spacecraft and Earth to figure how much Saturn’s gravity deformed the moon.

They then turned to computer models to match a 10-meter (33-foot) distortion with possible scenarios to explain what was going on. The more solid the moon’s interior, the less it would be impacted by Saturn’s gravity.

“The measurement is pretty conclusive about the existence of an internal ocean,” said lead researcher Luciano Iess, with Sapienza University in Rome, Italy.

“The presence of water does not imply life,” he added.

“But Titan has many interesting ingredients – hydrocarbons, a hydrological cycle and a thick atmosphere.”

Scientists have no idea if the ocean is in contact with rock, a possible source of minerals and other components believed to be needed for life.

Based on the Cassini findings, Titan’s suspected ocean lies about 100 kilometers (62 miles) beneath the surface.

Although the moon sports lakes of liquid hydrocarbons, such as methane and ethane, Titan’s ocean is probably mostly water.

“The subsurface ocean has to be made of water, or water mixed with a relatively small percentage of salts,” Iess said.

If the ocean were liquid hydrocarbons, the heavier surface ice would sink and Cassini would see a global hydrocarbon ocean on the surface, he added.

Scientists hope to refine gravity maps of Titan after additional Cassini flybys planned through 2017.

Cassini arrived at Saturn in 2004.