Scientists have announced that NASA’s decommissioned Spirit rover may have found evidence of alien life Mars in 2007, but scientists failed to pay attention at the time.
According to a new study photographs snapped in 2007 by the Spirit rover exploring the Martian surface appear to show structures that could be biosignatures of past microbial life forms on the planet.
The Spirit rover images of Silica outcrops in the Home Plate, a 300-square-foot plateau of layered rocks in the Columbia Hills area of the Gusev crater near the Martian equator, could be evidence of past microbial life on Mars overlooked until now, scientists say.
The study, titled “Silica deposits on Mars with features resembling hot spring biosignatures at El Tatio in Chile,” was conducted by scientists from the Arizona State University (ASU) and published on November 17, 2016, in Nature Communications.
While reviewing images of the Home Plate silica deposits and comparing them with similar features on Earth, ASU School of Earth and Space Exploration researchers Steven Ruff and Jack Farmer discovered nearly identical hot spring silica deposits called stromatolites at El Tatio, near the Atacama Desert in Chile.
The El Tatio silica deposits were created through the combined agency of hot springs (non-biological) and microorganisms (biological).
Conditions in El Tatio are similar to conditions in the Home Plate area of Mars. El Tatio hot springs are situated about 14,000 feet above sea level. The area has thin, dry air, low temperatures often dropping below freezing point in the night even in summer, and high levels of ultraviolet radiation in the day.
[Note: The images below show the silica deposits on Mars on the left and similar silica deposits at El Tatio, Chile, on the right]
Home Plate on Mars is also believed to have had active hot springs that formed the silica outcrops photographed in 2007 by Spirit rover (see photos below).
Similar silica structures or stromatolites, considered fossil remains of the earliest forms of life on Earth, are also found in Precambrian rocks of Western Australia.
Stromatolites are formed when colonies of microbes trap sediments which react with calcium carbonate under moist conditions, leading to accumulation of limestone layers.
“We went to El Tatio looking for comparisons with the feature found by Spirit at Home Plate.”
The similarity of the silica deposits in the Home Plate plateau of Mars to stromatolites in El Tatio has raised questions whether the Martian structures were also formed like stromatolites on Earth through the combined agency of hot springs and primitive microbial life forms.
“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 scientists said, according to Express.
“The similarities raise the possibility that the Martian silica structures formed in a comparable manner.”
“Our results show that conditions at El Tatio produce silica deposits with characteristics that are most Mars-like of any silica deposits on Earth,” Ruff said, according to the Telegraph.
“The fact that microbes play a role in producing the distinctive silica structures at El Tatio raises the possibility that the Martian silica structures formed in a comparable manner — in other words with the help of organisms that were alive at the time.”
This is the second time in recent years that a team of scientists has claimed evidence of life on Mars discovered in the past but overlooked at the time.
A team of scientists had claimed in 1976 to have found evidence of life on Mars but their work was ignored by their peers.
The team of scientists involved in the Viking Labeled Release (LR) experiment had concluded that soil collected from Mars by the Viking Landers showed signs of microbial life. The labeled release experiments to test for biosignatures of microbial life on Mars were carried out by two Viking crafts that landed at two separate locations on the Red Planet about 4,000 miles apart.
According to the scientists, the results of the LR experiments were remarkably similar to identical tests conducted on soils collected from California, Alaska, and Antarctica.
But other scientists rejected the results partly because the LR experiment results were not backed by results from the other two life-seeking experiments conducted by the probes.
But recently, in 2012, a team of scientists conducted fresh mathematical analysis of the data and concluded that the LR experiments might have found evidence of microbial life in Martian soil.
“It’s very possible that if you have microbes, they’re living a couple of inches beneath the soil, close to water ice,” a study team member Joseph Miller, from the University of Southern California, said, according to National Geographic.
Scientists have always believed that Mars offers the best chances of finding extraterrestrial life because there is evidence that the planet once had running liquid water and a thick atmosphere.
Discovery of methane in the planet’s atmosphere in 2014 also raised hopes of finding life on Mars because about 90 percent of methane on Earth is produced by living organisms.
NASA decommissioned the Spirit rover in 2011 after the front wheel broke and the rover got stuck in Martian soil.
Unfortunately, the currently active rovers Curiosity and Opportunity are too far away to travel to Home Plate to conduct further investigations. But scientists hope to be able to conduct fresh investigations in the Home Plate area during a subsequent mission in 2020.
[Featured Image by NASA/JPL/Cornell University, Maas Digital LLC/Wikimedia]