Showing posts with label Saturn. Show all posts
Showing posts with label Saturn. Show all posts

Tuesday, December 16, 2008

Saturn's largest moon has 'active ice volcanoes'


Saturn's largest moon may have active ice volcanoes that spew ammonia and methane instead of lava, scientists say.

The international Cassini spacecraft took radar images that point recent to liquid flows on the surface of Titan.

The findings suggest the moon could contain active 'Cryovolcanoes', or icy volcanoes.


Rosaly Lopes, a Cassini radar team scientist, said: 'Cryovolcanoes are some of the most intriguing features in the solar system.

'To put them into perspective - if Mount Vesuvius had been a cryovolcano, its lava would have frozen the residents of Pompeii.'

Previous flybys and a probe sent to the surface in 2005 suggested ice volcanoes once existed on the moon.

But the latest data 'not only indicate that cryovolcanism has been going on on Titan in the recent geologic past, but might even be going on on Titan today,' Cassini scientist Jonathan Lunine from Arizona University said.

Titan is one of the few bodies in the solar system with a significant atmosphere.

Scientists believe methane gas breaks up in the atmosphere and forms clouds that rain methane. The source of the methane remains a mystery.

Scientists favouring the volcanic theory say methane eruptions from Titan's interior could explain the moon's smoggy atmosphere.

Data from the spectrometer instrument on Cassini found bright spots on two regions on Titan. In one of the regions, scientists found evidence of ammonia frost that they interpreted as coming from the interior.

The results were presented at an American Geophysical Union meeting in San Francisco but not everyone is convinced by the evidence.

Planetary scientist Jeff Moore of NASA's Ames Research Center said the results were intriguing, but inconclusive.

'Something is going on. Exactly what it is isn't clear,' he said.

The Cassini spacecraft has been orbiting Saturn and studying its rings and moons since 2004.

Today NASA revealed the craft had also found evidence of a crust forming on Enceladus.

The process, in which the surface splits and spreads apart is similar to that performed on the Earth, and increases the likelihood of a liquid-water sea beneath the surface.

Carolyn Porco, Cassini's imaging group team leader told the BBC: 'Bit by bit, we're accumulating evidence that there is liquid water on Enceladus'

New crusts on Enceladus are created by 'tiger stripes', cracks similar to those that split mid-ocean ridges on our own planet.

Dr Paul Helfenstein from Cornell University, who worked on the project said: On Enceladus what we see is a type of spreading but it is strongly asymmetric - it's like a conveyor belt.

'If it's true it's coming up from a convection well, it seems to be only pushing in one direction. It does happen on Earth, but only in very peculiar situations.'

Thursday, November 27, 2008

Supersonic plumes of water erupt from Saturn's moon raising hopes of micro life under surface

Huge plumes of water vapor and ice particles are spewing from Saturn's moon Enceladus at supersonic speeds, scientists report.

When the Cassini spacecraft flew through a gigantic geyser of dust and gas close to the surface of Enceladus, it collected samples of ice and gas.

Astronomers say the plumes may be erupting from an underground ocean, which would make Enceladus the third place in the solar system suspected to support life, even if only microbial organisms.
'There are only three places in the solar system we know or suspect to have liquid water near the surface - Earth, Jupiter's moon Europa and now Saturn's Enceladus,’ Joshua Colwell, one of the researchers at the University of Central Florida, said.

‘Water is a basic ingredient for life and there are certain implications there,’ he added.
Images taken by the Cassini spacecraft in 2005 revealed huge gysers shooting from fissures in the south pole of Enceladus, reminiscent of the famed Old Faithful at Yellowstone National Park in the United States but on a grand scale.

But the latest mission suggest that the gas and dust are spewing at more than 1,300 mph - faster than sound - making the case that Saturn is hiding a reservoir of liquid water.

Data from Cassini's Ultraviolet Imaging Spectrograph instrument, a high-tech imaging instrument, suggest that cracks extend below the surface and act as nozzles that channel water vapor from an underground liquid water reservoir.

Focusing the instrument at a distant flickering star also showed that the water vapours – which intermittently blocked its starlight – form narrow jets as they blast into space.

'We think liquid water is necessary for life and there is more evidence that there is liquid water there,' said lead researcher Candice Hansen of NASA's Jet Propulsion Laboratory in Pasadena, California.

'You also need energy, you need nutrients, you need organics. It looks like the pieces are there. Whether or not there's actually life, of course, we can't say.'
 

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