BaseLine 07-17-2004 12:01 PM Ammonia on Mars could mean life   Quote: Ammonia on Mars could mean life Ammonia may have been found in Mars' atmosphere which some scientists say could indicate life on the Red Planet. Researchers say its spectral signature has been tentatively detected by sensors on board the European Space Agency's orbiting Mars Express craft. Ammonia survives for only a short time in the Martian atmosphere so it must be getting constantly replenished. There are two possible sources: either active volcanoes, none of which have been found yet on Mars, or microbes. Suite of molecules "Ammonia could be the key to finding life on Mars," one US space agency (Nasa) scientist told BBC News Online. Spectral evidence of the gas was seen by the Planetary Fourier Spectrometer (PFS) on Mars Express. Professor Vittorio Formisano, principal investigator for the instrument, is expected to release details of new findings from the PFS at an international conference being held next week in Paris. The PFS is sensitive to radiation in the spectral region of 1.2-5 microns and 5-50 microns - a region rich with important molecules such as water and carbon dioxide. Ammonia has a spectral line at 10 microns. Although Mars Express has been in orbit around Mars since December 2003, scientists have so far only analysed a fraction of the data the PFS has produced. Researchers say this is because they are still coming to terms with the complexities of the PFS as well as coping with some nagging power problems on Mars Express. So far the PFS has observed a depletion of carbon dioxide and an enrichment of water vapour over some of the large extinct volcanoes on Mars. But it is the detection of minor compounds, possible in the sensors high-resolution mode, which are causing excitement. The detection of ammonia comes just a few months after methane was found in the Martian atmosphere. Methane is another gas with a possible biological origin. Ammonia is not a stable molecule in the Martian atmosphere. If it was not replenished in some way, it would only last a few hours before it vanished. One possibility the scientists had to rule out was that the ammonia came from the air bags of the failed Beagle 2 mission. Analysis revealed that the ammonia's distribution was not consistent with this explanation. Life on Mars? The importance of ammonia is that it is a compound of nitrogen and hydrogen. Nitrogen is rare in the Martian environment but because no form of terrestrial life can exist without it, the presence of ammonia may indicate that Martian microbial life is hoarding it. "There are no known ways for ammonia to be present in the Martian atmosphere that do not involve life," the Nasa scientist said. The twin US rovers that landed on the Red Planet in January will be unable to answer the question of the ammonia's origin as they are designed for geological work. But future missions could include sensors to analyse the ammonia to determine if it has a biological or volcanic origin. Lava deposited on to the surface, or released underground, could produce the gas. But, so far, no active volcanic hotspots have been detected on the planet by the many spacecraft currently in orbit. source

BaseLine 07-19-2004 11:25 AM NASA is on a roll... Quote: Mars rover finds that water persisted Surface water on Mars existed across a significant span of time, not just for years but eons, suggest new findings made by NASA's Mars rover Opportunity. Within a few weeks of its landing on Mars in January 2004, Opportunity revealed what was uppermost on the twin rovers' agenda: that bodies of liquid water once existed on the surface of Mars. But the evidence proved what could have been only a solitary event - a single wet episode. The new discovery, reported by NASA's Jet Propulsion Laboratory on Friday, pushes the boundaries significantly further back, into geological timescales. After motoring down several metres into a the large Endurance crater, Opportunity has found what science team member Jack Farmer of Arizona State University calls "razorback," a ridge of thin, jagged vertical plates sticking up at the edge of a flat expanse of bedrock. The team suspects that the ridge is a layer of rock that formed when earlier layers of rock cracked, and mineral-laden water percolated through the cracks leaving deposits behind, forming veins, or "fracture fill". Those deposits formed rock harder than the surrounding material, so as the rock eroded away it left this harder ridge behind. The fractures, Farmer says, may have been caused by the impact that produced the crater. Salt crystals The surrounding rock is the very bedrock that Opportunity has been studying ever since its arrival on Mars, first in a tiny crater called Eagle, and for the last month in the much larger Endurance crater. In both places, the layered bedrock has provided multiple lines of evidence - unusual minerals, voids left by dissolved salt crystals, and hematite spheres - showing that liquid water once flowed there. And at the Endurance site, this evidence for water extends through five successive geological layers, or units, extending back in time from the original layer. But the new "razorback" find dramatically extends this record. Formation of such crack filling material requires liquid water, but at a time so much later that these different layers of marine sediment had time to be compacted into stone, hard enough to form sharp cracks rather than crumbling. The actual time span has not been estimated, but it reveals enough time to strengthen the possibilities that life could have evolved on Mars. The team is expects to spend most of this week analysing the razorback with the rover's various spectrographs. Dwindling sunlight Meanwhile, there was great excitement on the other side of Mars. The rover Spirit, skirting the edge of a hill called West Spur on the edge of Columbia Hills and preparing to drive up it, has now driven over an outcrop of bedrock - something that had never been seen before at Spirit's site in Gusev crater. "Eureka! We have found it!" exclaimed Matt Golombek of NASA-JPL, a science team member. "Spirit has an outcrop under the rover wheels. And an outcrop is the currency for geologists." Studying it should help reveal the geological history of the Gusev site. Both rovers are in the most scientifically interesting and technically challenging terrain yet, though both are also somewhat limited by the dwindling sunlight and plummeting temperatures as midwinter approaches in September. And both remain healthy, despite one balky wheel on Spirit, having more than doubled their 90-day design lifetimes. link

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