Mars’ Red Planet has long been a subject of interest when it comes to the search for life beyond Earth. Ever since the discovery of methane on Mars, scientists have wondered if the planet might harbor life. Researchers have now found where to look: deep under the surface of a broad Martian plain.
The presence of methane on Mars is an intriguing clue, but its seasonal fluctuations have raised more questions than answers. While orbiting satellites haven’t detected any significant signs of the molecule, rovers on the surface have observed variability that suggests a particular type of life might exist. However, with temperatures often below freezing and limited atmosphere, Mars appears to be uninhabitable.
Scientists, however, can look to Earth for potential habitats for Martian life. On our planet, life has adapted to every available niche, from atmospheric gases to deep-sea environments. A specific domain, Archaea, consists of single-celled creatures that extract energy from their surroundings. Methanogens, a type of Archaea, thrive in environments with hydrogen and can produce methane as waste.
Researchers have scoured Earth for potential analogues to Martian environments, focusing on conditions similar to those found on Mars. They identified three main habitats: microscopic fractures deep within the Earth’s crust, freshwater lakes buried under glaciers or ice caps, and extremely saline, oxygen-deprived deep-sea basins.
In a new paper submitted to Astrobiology, scientists mapped out temperature ranges, salinity levels, and pH values across various sites on Earth. They then surveyed these sites for molecular hydrogen, which is the primary food source of methanogens on Mars.
The study found that two families, Methanosarcinaceae and Methanomicrobiaceae, are most flexible and can thrive in conditions resembling Martian environments. By analyzing available data about Mars, researchers believe that liquid water might exist beneath the surface, with Acidalia Planitia offering the best possible conditions for life.
With temperatures only warm enough to support liquid water at a depth of 2.7 to 5.5 miles (4.3 to 8.8 kilometers), scientists are now calling for further exploration. Joining the search for life on Mars could provide groundbreaking insights into the possibility of extraterrestrial life and its potential habitats.
Source: https://www.space.com/space-exploration/search-for-life/we-finally-know-where-to-look-for-life-on-mars