Could there by life in Mars. Why not?

Deposits of silica detected on Mars in 2007 by the roving robot Spirit were formed by volcanic vapors or hot-spring-type events crossing through soil. They could also contain traces of past life, scientists reported in a study out Thursday.

On Earth, hydrothermal deposits teem with life, and the associated silica deposits typically contain fossil remains of microbes. But we don’t know if that’s the case here," researchers noted, "because the rovers don’t carry instruments that can detect microscopic life."

"What we can say is that this was once a habitable environment where liquid water and the energy needed for life were present," he added "If there were organisms living there," he said, "our terrestrial experience shows that microbes can easily be entrapped and preserved in the deposits." Silica is an excellent medium for capturing and preserving traces of microbial life, he added.

NASA landed two Mars rovers, Spirit and Opportunity, on opposite sides of the planet in January 2004 to scope out rocks showing the presence of water. Now the rovers are more than four Earth years into a trek designed to go just three months.

While dust has collected on their solar panels and they have had some mechanical wear, both are still exploring.