Secrets in the sand on Mars
2008-06-14 22:01
Washington - About three weeks after it landed on Mars, the Phoenix lander has collected particles that offer a snapshot of millions of years of life on the Red Planet, the team behind the probe said Friday.
Nasa's $420m lander has also possibly located ice and is half way to offering scientists on Earth a 360-degree view from its landing site in the Martian polar region, with rocks and hills fading into the dusty distance.
"We're getting about twice the data volume we were told to expect," said Peter Smith, Phoenix principal investigator at the University of Arizona.
The team is hoping to find evidence of the existence of water and life-supporting organic minerals in the polar region, on the basis that the similar areas on Earth preserve traces of climate change and signs of life.
For the past week, Phoenix's robotic arm, which looks like a back-hoe, has been digging into the soil around it and uncovered a bright surface about 5cm below the soil that could be ice.
"Not everybody's sure that this is ice. There's been some debate within our team," said Smith. "The debate centres around perhaps there's a salt layer above the ice, which would be very bright and white also."
The team was pretty sure they would find ice, but not whether they had already found it, he explained during a televised briefing in Tuscon, Arizona, adding that scraping further into the surface was "really a high priority."
Some of the soil collected so far was be "very clumpy, its very sticky," Smith said, and initially got stuck on one of Phoenix's oven-like instruments, the Thermal and Evolved-Gas Analyser (TEGA). Tests are now underway.
Other finer particles meanwhile have been collected in another testing instrument and reveal the history of soil on Mars, going from black glassy particles to more weathered ones, Phoenix team member Tom Pike said.
"What we're looking at here is a potted history of Martian soil," he said.
He described "black glassy particles that over millions, even billions of years have been slowly weathering down, becoming iron-enriched which gives the organic material its characteristic (red) colour, and we're seeing that process captured on the variety of particles that we're looking at." - Sapa-AFP
- SAPA