Pasadena (CA) - NASA's Mars Reconnaissance Orbiter has identified Martian rocks containing a relatively young hydrated mineral similar to opal. The first conclusion is that there was water on Mars much more recently than previously believed and life as we know it may have been supported for a much longer period of time.

The orbiter’s “Compact Reconnaissance Imaging Spectrometer” has found wide-spread evidence hydrated silica, commonly known as opal. NASA said that these minerals formed where liquid water altered materials created by volcanic activity or meteorite impact on the Martian surface. The mineral was found in the Martian canyon system called Valles Marineris.

What makes this discovery special is the fact that the opaline silicates are relatively young, at least in astronomy, and are the youngest revealing evidence of water so far. The minerals are about 2 billion years old, which is substantially below the age of Clay-like phyllosilicates (3.5 billion years) and hydrated sulfates formed from the evaporation of salty and sometimes acidic water (3 billion years).

"We see numerous outcrops of opal-like minerals, commonly in thin layers extending for very long distances around the rim of Valles Marineris and sometimes within the canyon system itself," said Ralph Milliken of NASA's Jet Propulsion Laboratory.

NASA noted that, the orbiter's spectrometer observed opaline silica with iron sulfate minerals, either in or around dry river channels, which suggests that the acidic water remained on the Martian surface for an extended period of time. "What's important is that the longer liquid water existed on Mars, the longer the window during which Mars may have supported life," Milliken said. "The opaline silica deposits would be good places to explore to assess the potential for habitability on Mars, especially in these younger terrains."

In the meantime, NASA’s Phoenix operation on the Mars surface seems to be winding down. Originally scheduled to last 90 days, Phoenix has completed a fifth month of exploration in the Martian arctic. But the Martian northern hemisphere is shifting from summer to fall and the lander is generating less power due to shorter days and fewer hours of sunlight reaching its solar panels. At the same time, the spacecraft requires more power to run several survival heaters that allow it to operate even as temperatures decline, NASA said.

Scientists will be shutting down four survival heaters over the next few weeks, one at a time. While the shutdown will save power, they keep the electronics of the lander operational. As each heater is disabled, some of the instruments are also expected to cease operations. NASA said it will be redirecting the energy saved “to power the lander's main camera and meteorological instruments until the very end of the mission.”

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