NASA’s Spirit Rover Stumbled Upon Telltale Signs of Potential Past Life on Mars
Spirit rover, one of NASA’s wheeled explorers to the Red Planet, may have encountered potential signs of past life on the planet. Or at least that’s what the scientists at Arizona State University are reporting.
In order to make their case and put it into a more familiar light for the rest of us, the team has made some comparisons between the layered rocks Spirit rover uncovered during its third year of expeditions, with similar features found within active hot springs and geysers located in northern Chile, called: the El Tatio Geysers. This comparison was comprised in a scientific paper called: “Silica deposits on Mars with features resembling hot spring biosignatures at El Tatio in Chile.”
As reported in the journal Nature Communications, field work at Chile’s El Tatio geysers, done by a team from Arizona State University, has shown that the nodular and digitate silica structures found there closely resemble those found on Mars by Spirit. These include a combination of biotic and abiotic processes which in turn resulted in those complex sedimentary structures.
“Although fully abiotic processes are not ruled out for the Martian silica structures, they satisfy an a priori definition of potential biosignatures,” the researchers wrote in the study.
Spirit landed on Mars in January 2004, a few months ahead of its twin. Opportunity. Each landed on different parts of the planet and were tasked with searching for signs of past water activity throughout the duration of their missions. Spirit encountered these outcrops of composed opaline silica in an ancient volcanic hydrothermal, Gusev crater.
An origin via either fumarole-related acid-sulfate leaching or precipitation from hot spring fluids was considered possible.
“However, the potential significance of the characteristic nodular and [millimeter]-scale digitate opaline silica structures was not recognized,” the scientists noted in the new study.
The geographical and environmental conditions at El Tatio, in that there is a rare combination of high altitude, low air pressure, low precipitation, high evaporation rate, high ultraviolet irradiance and common diurnal freeze. These conditions can offer a great comparison to those found on Mars.
“Such conditions provide a better environmental analog for Mars than those of Yellowstone National Park (USA) and other well-known geothermal sites on Earth,” suggested the scientific team. “Our results demonstrate that the more Mars-like conditions of El Tatio produce unique deposits, including biomediated silica structures, with characteristics that compare favorably with the Home Plate silica outcrops. The similarities raise the possibility that the Martian silica structures formed in a comparable manner.”