Hot Springs — and Life? — on Mars

A stuck wheel in the Martian dust turned out to be a lucky accident for the rover Spirit. As the crippled wheel was dragged along, it dug up a trench revealing a white layer of silica apparently produced by hydrothermal vents like the famous hot springs at Yellowstone. And where there was once hot water, there might have been life. On Earth, the only way to have this kind of silica enrichment is by hot water reacting with rocks,” Dr. Ruff said, and noted that this part of Mars — dubbed Home Plate by the researchers — was a logical spot for the water. “Home Plate came from an explosive volcanic event with water or ice being involved. We saw where rocks were thrown into the air and landed to make small indentations in the soft, wet ash sediment around the vent.” Another of the co-authors, Jack Farmer of A.S.U., said: “On Earth, hydrothermal deposits teem with life and the associated silica deposits typically contain fossil remains of microbes.” The researchers aren’t sure if that’s the case on Mars, because the Spirit rover doesn’t carry instruments that can detect microscopic life. “What we can say,” Dr. Farmer added, “is that this was once a habitable environment where liquid water and the energy needed for life were present.”