There Is Now An Easy Way To Look For Living Organisms On Mars

The search for life beyond Earth is a complicated affair. Elsewhere in the Solar System, we are looking for microorganisms, and our robotic explorers do not have the ability to do the things that we do in the lab. There are many ways for rovers and spacecraft to look for evidence of life, recent or ancient. Now, researchers report a new method that could confirm the presence of living things using old tech.

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If there is life on Mars, and it is not too dissimilar from Earthly life, it is made of cells. Those cells will have membranes, and those membranes will be made of specific fatty molecules known as intact polar lipids (IPLs). Graduate research Solomon Hirsch and his supervisor Professor Mark Sephton from Imperial College London looked at how rovers could look for these molecules and found something very exciting.

We haven't found any evidence of aliens yet, obviously, but if we did find something, the first question after we know it is a signal of life, would be: is it living right now? 

Solomon Hirsch

NASA’s Curiosity and Perseverance, the upcoming European Space Agency Rosalind Franklin rover, and even the Viking probes that landed on Mars in the 1970s, are equipped with this instrument: a gas chromatograph mass spectrometer (GC-MS). It works by heating up the sample and then identifying the chemical signature of specific molecules, and while versatile and in many cases a gold standard, it is not a machine without limitations.

The team had to test what a GC-MS would make of the IPLs. They found a clear spike in the graph from the GC-MS of the IPLs of living bacteria.

“We haven't found any evidence of aliens yet, obviously, but if we did find something, the first question after we know it is a signal of life, would be: is it living right now? This is a technique we could use using current systems to detect whether something's living or not,” Hirsh told IFLScience.

The IPLs are a great tracer for living organisms. They have been used historically to evaluate the biomass in many different environments, including the ocean floor. The fact that missions already on Mars can do the same is very exciting.

“Basically, when something dies, these lipids are some of the first things to break down. This can happen within hours or maybe just a few days. So essentially, if we see a signal that's associated with these compounds, then we can assume that the organism there is living or very, very recently living at least,” Hirsch told IFLScience.

The team is now looking at instruments that are traveling towards the icy moons of Jupiter to see if those, too, could easily spot these IPLs. Maybe an errant cell has been thrown into space by a geyser...

The study is published in the journal npj Space Exploration.