sábado, 29 de noviembre de 2008

Water vapour discovered on Saturn's moon

Huge plumes of water vapour and ice particles are bursting out from Saturn's moon Enceladus at supersonic speeds in a way that strongly suggests they come from liquid water down below the icy surface, scientists have said

 Artist's impression of the Cassini spacecraft passing through plumes from geysers that erupt from giant fissures in the moon's southern polar region  Photo: REUTERS
Artist's impression of the Cassini spacecraft passing through plumes from geysers that erupt from giant fissures in the moon's southern polar region Photo: REUTERS

The research, published in the journal Nature, offers new evidence that the moon may harbor an underground ocean of water, meaning conditions might exist that could support life, even if only microbial organisms.

'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.'

Scientists are aware of only three places where liquid water exists near the surface of a planet or other body - Earth, Jupiter's moon Europa and now Enceladus.

In July Nasa’s Phoenix Mars Lander confirmed the presence of ice on Mars.

The previous month the spacecraft uncovered a bright white layer just two inches below the surface, which disappeared four days after it was exposed to sunlight, leading scientists to believe it was ice.

After examining a soil sample from a trench approximately two inches deep, the claim was confirmed.

In a Nasa statement, William Boynton of the University of Arizona said: “We have water.

“We’ve seen evidence for this water ice before in observations by the Mars Odyssey orbiter and in disappearing chunks observed by Phoenix last month, but this is the first time Martian water has been touched and tasted.”

Phoenix principal investigator Peter Smith, of the University of Arizona, said: “Mars is giving us some surprises.

“We’re excited because surprises are where discoveries come from.”

Scientists will now begin asking whether the frozen water could have been liquid at some point in the planet’s history, which would have created an environment in which life could have evolved.

Experts believe that if life ever existed on Mars, it could still survive today in isolated pockets beneath the soil.

source: telegraph.co.uk

jueves, 27 de marzo de 2008

Saturn's Moon of Enceladus Has `Recipe for Life'

Saturn's Moon of Enceladus Has `Recipe for Life,' NASA Says

By Alex Morales

March 27 (Bloomberg) -- Saturn's moon Enceladus has a ``surprising organic brew,'' containing most of the ingredients needed for life, erupting in geysers from beneath its surface and spewing into the atmosphere, NASA said.

Instruments aboard the U.S. National Aeronautics and Space Administration's Cassini spacecraft revealed a concentration of water vapor, carbon dioxide, carbon monoxide and organic material 20 times denser than expected, the agency said in an e-mailed statement. Temperatures were also higher than previously noted.

``Enceladus has got warmth, water and organic chemicals, some of the essential building blocks needed for life,'' Dennis Matson, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, said in the statement. ``We have quite a recipe for life on our hands, but we have yet to find the final ingredient, liquid water.''

Saturn's moons have long been of interest to scientists, who say the largest, Titan, may resemble an early version of Earth, providing clues to how the planet developed. Enceladus, the sixth-largest moon, had already surprised scientists when in 2005 they detected a ``significant atmosphere.''

The latest findings also revealed that Enceladus's chemical components resemble those found in comets, raising questions about the formation of Saturn, Hunter Waite, principal investigator for one of Cassini's instruments, said in the statement, without elaborating.

Cassini also measured temperatures near the south pole of Enceladus of minus 93 degrees Celsius (minus 135 Fahrenheit), about 17 degrees warmer than previously measured in the region.

Liquid Water

``The surprisingly high temperatures make it more likely that there's liquid water not far below the surface,'' John Spencer, another project scientist, said in the statement, e- mailed yesterday. ``These spectacular new data will really help us understand what powers the geysers.''

Enceladus, with a diameter of 499 kilometers (310 miles), lies some 238,020 kilometers from the ringed planet. The moon is one of the most reflective objects in the solar system, bouncing back nearly all visible light that hits it.

Cassini was launched from Cape Canaveral, Florida, in 1997, bearing the Huygens probe. The craft traveled more than 2.2 billion miles before entering orbit around Saturn in 2004. In January 2005, Huygens was sent down through Titan's atmosphere, gathering data on the moon's physical, chemical and electrical properties.

Cassini has continued to orbit Saturn, beaming back information on the ringed planet and its moons. The $3.2 billion Cassini-Huygens mission is a collaboration between NASA, the European Space Agency and the Italian Space Agency.

Source bloomberg.com