There have been a lot of looney shapes spotted on Mars' geological landscape in recent decades, many of which have stirred wild suggestions that there once was, or still is, Martian life. However, a new proposal by a pair of scientists might actually be onto something.
In 2008, NASA’s Spirit rover captured an image showing lumpy “cauliflower” mineral deposits inside of Mars’ Gusev crater. Smithsonian has reported that scientists are now thinking these innocuous-looking lumps and bumps could be the remnants of life on Mars.
Planetary geologist Steven Ruff and geobiologist Jack Farmer, both of Arizona State University in Tempe, found a distinct similarity between these Martian “micro-digitate silica protrusions” and structures found in the harsh badlands of El Tatio in the Atacama Desert of Chile. They presented their speculation a couple of months ago in a paper released at the American Geophysical Union.
Over 3 billion years ago, parts of Mars were geyser-filled hydrothermal lands. The region where the silica protrusions were found, near the Gusev crater, is believed to have once housed these hot springs and geysers.
The red planet of Catarpe in the Atacama Desert, Chile. Image credit: sunsinger/Shutterstock.
The area of the Atacama Desert the researchers studied is often compared to Mars, not least because of its red soil. The environment is so alike that NASA uses the region to fine-tune their robotics and practice their lander-driving skills. Its high elevation means it receives a large amount of ultraviolet radiation, much like the high levels of radiation experienced on Mars’ surface. Along with this punishing trait, it receives less than 100 millimeters (3.9 inches) of rain per year, and its temperatures teeter between -25°C (-13°F) and 45°C (113°F). El Tatio is also the largest geyser field in the Southern Hemisphere, with around 80 active geysers.
Nearby these geysers in El Tatio, the researchers found similar cauliflower-like structures, which were created by microbial processes. It's this finding that made Ruff and Farmer believe that the "cauliflowers" near the ancient Martian geyser could also have once been formed by microbes.
Lumpy structures formed by microbial life have also been found at the geothermal springs of Yellowstone National Park and New Zealand's Taupo Volcanic Zone.
Unfortunately, the idea that these structures could suggest a past microbial life is still very much a “could” at the moment. As Ruff and Farmer conceded themselves, it’s hard to prove biology from 54.6 million kilometers (33.9 million miles) away. The scientists also encouraged more researchers to look into what these mysterious little lumps could be. In the meantime, making Earthly comparisons is still the best bet we have when trying to find the “footprints” of ancient microorganisms on distant planets.