NASA is still not sure whether its Phoenix lander has found a place where life could have existed on Mars. But scientists working with the US space agency, computer models they have been using to predict what the weather would be like on the Red Planet are wrong, and more accurate models would give a better picture of its past.
Speaking at the opening day of the American Geophysical Union conference in San Francisco,
Phoenix mission scientists laid out the early harvest from five months of robotic operations on the northern polar region of Mars.
Analyzing ice and soil samples for organic material, a process that is still under way, the Phoenix science team collected daily weather reports, information considered critical to learning if the planet could have supported water long enough for life to evolve.
Phoenix saw dusty summer days slip into cloudy fall, replete with ground fog, snow and frost. Global climate models that are running on Mars would not predict this but the polar region is going to force us to make changes.
More accurate computer models would give scientists a clearer picture of what happened in Mars' past, particularly when the planet's axial tilt, or obliquity, was greater than it is now. Without a large moon for stabilization, Mars' polar regions periodically shift off axis by more than 35 degrees. During those times, the sun would rise higher in the sky above the Martian poles, making for warmer summers.
Scientists are trying to determine if there was ever a period of time when it would have been warm enough for water, considered a key ingredient for life as we know it. If the scientists can update these global circulation models and we can understand better about the polar weather, then they can look back in time to see if liquid water was ever a dominant influence on this soil in this location.
Scientists had problems delivering soil samples into Phoenix's tiny ovens for analysis because the soil turned out to be rather clumpy, not dry and dusty like the soil at sites where other probes have landed. Though frustrating, the discovery also spurred new questions about how water is moving through the ice, soil and atmosphere.
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