A tested laser on Earth could detect past life on Mars

This device has been tested on Earth demonstrating that it can detect microbes fossils in plaster samples that are an analogy close to sulfate rocks on Mars.

“Our findings provide a methodological framework to detect biofirms in Martian sulfate minerals, which could guide future Mars exploration missions,” said Tocef Sellam, a doctoral student at the Institute of Physics of the University of Bern and the first author of the article in Frontiers in Astronomy and Space Sciences.

“Our laser ablation ionization mass spectrometer, a prototype instrument for space flights, can effectively detect biofirms in sulfate minerals. This technology could be integrated into future explorers or landing modules of Mars for in situ analysis. ”

Billions of Mars, Mars dried. The plaster and other sulfates were formed when the puddles evaporated, leaving behind minerals that rushed out of the water and potentially fossilizing any organic life that would remain. This means that if microbes such as bacteria lived there, traces of their presence could be preserved as fossils.

“The plaster has been widely detected on the Martian surface and is known for its exceptional fossilization potential,” said Sellam in a statement. “It is quickly formed, catching microorganisms before decomposition occurs and preserving biological structures and chemical biofirms.”

But to identify these microbial fossils, we must first demonstrate that we can identify similar fossils in places where we know that such microbes existed, such as the plaster formations of the Mediterranean that developed during the Messina salinity crisis.

“Messina’s salinity crisis occurred when the Mediterranean Sea was separated from the Atlantic Ocean,” said Sellam. “This caused a rapid evaporation, which caused the sea to become hypersaline and deposit thick layers of evaporites, including the plaster. These deposits provide an excellent land analogue for Martian sulfate deposits. ”

The scientists selected an instrument that could be used on a space flight: a miniature mass spectrometer fed by laser, which can analyze the chemical composition of a sample with a detail as fine as a micrometer.

The researchers took plaster samples of the Sidi Boutbal quarry (Algeria) and analyzed it with a mass spectrometer and an optical microscope, following criteria that can help distinguish between possible microbial fossils and natural rock formations, such as irregular, sinuous and potentially hollow morphology, as well as the presence of chemical elements necessary for life, carbon material as clay or dolomite that can be influenced by the presence of bacteria.