Potential signs of life on Mars may be easier to find than first thought

A school science experiment answers questions that are out of this world. Although some feared that any traces of organic matter on Mars might be obscured by the planet’s geology, new research suggests that might not be the case.

A group of budding young researchers have helped demonstrate how to find evidence of life on Mars.

Students from St Bernard’s Convent High School in Westcliff-On-Sea, Essex, helped scientists from the Natural History Museum and University College London in an experiment to determine what evidence potential ancient life would have could leave on the red planet.

Students at the all-girls school, of which Dame Helen Mirren is an alumni, prepared samples of a microbial mat which were transported to the edge of space in a balloon to mimic conditions on Mars. This allowed the researchers to examine the changes that the cold, dry atmosphere was causing to signs of life.

Connor Ballard, a Ph.D. The student who led the study says: “We wanted to involve the students in as many aspects of this research as possible, and they were really engaged throughout. »

“We know that science suffers from a lack of diversity, so being able to work with these young women has been a pleasure. I know many of them want to pursue a career in science, so we really hope this will help them in their future. “

Dr Louisa Preston, Scientific Associate at the Natural History Museum and co-author, adds: “It’s really great for these young women to already have an article published with their name to celebrate their work.”

“It is very important to engage children in science and we hope this will inspire other students as well.”

The results of the study were published in the journal AAS Research Notes.

Markers on Mars

Since the 1990s, six rovers have successfully landed on the surface of Mars to learn more about our neighboring planet. Many of these missions have attempted to answer a big question: has there ever been life on Mars?

It’s not as strange as it might seem. Although a human would not survive on the surface of Mars, there are many microbes on Earth that might find its dry, carbon dioxide-rich atmosphere very hospitable.

We hope that if it ever existed, Martian life left traces in the form of physical or chemical markers called biosignatures. But identifying these signs could be tricky. High levels of radiation, extreme temperatures and weather conditions on Mars could have damaged or obscured the markers, making them difficult to detect.

To explain this, the researchers wanted to know what telltale signs remained when the biosignatures decayed. The team was particularly interested in the effect that gypsum might have on these panels.

On Earth, this mineral is found in dry lakes, and it has been suggested that on Mars it may have preserved the organic molecules of any life that might have lived in any liquid water. But this poses problems.

“While gypsum could be effective at preserving organic materials, it could also make them harder to find,” says Connor. “The problem with working in infrared is that many of the fundamental features of gypsum have absorption characteristics that mask the organic peaks in the spectrum. It’s a bit of a trap.”

Working with the students, the team decided to simulate what signs of ancient life on the Red Planet might look like using the collections of the Natural History Museum.

Fly high

To simulate possible Martian biosignatures, the team faced two challenges: finding a proxy for Martian life and simulating conditions on the planet.

If life existed on Mars, it is thought that it could have taken the form of microbial mats. These are collections of bacteria and other microbes that have created some of the oldest evidence of life on Earth. It is therefore not unreasonable to assume that life on Mars could have followed a similar path.

As part of her research, Louisa worked with samples of microbial mats from the Natural History Museum collection.

“I worked with microbial mats collected during the Discovery expedition, led by polar explorer Robert Falcon Scott in the early 1900s,” she explains. “These rugs are well preserved and, despite their age, still exhibit strong biosignatures.”

“That made it a good option to use here, and I think Robert Falcon Scott would be happy that, more than a century later, a sample from his expedition is still innovative.”

Now that they had found their proxy, the team needed to simulate conditions on Mars. To solve this problem, Louisa and her team turned to a company called Thales Alenia Space, which has been launching weather balloons carrying school science experiments to the far reaches of space since 2014.

By taking the specimens to the far reaches of space, it was hoped that they would experience conditions similar to those found on the Red Planet.

Once the balloon was ready to launch, students at the school were able to mix tiny samples of the microbial mat with gypsum in different proportions before sealing the samples in plastic containers. Half were left on Earth as a control, while the others were raised about 30 kilometers above Earth before being parachuted safely to the ground.

The returned samples were then scanned using infrared spectroscopy, a technique that identifies the composition of a sample by examining how it absorbs infrared radiation. Analyzes of the control samples revealed that higher levels of gypsum in the mixture masked the biosignatures of the microbial mat.

However, for samples that had traveled to the far reaches of space, the situation was different. Exposure to high altitude had caused the gypsum to dry out, meaning that certain aspects of the carpet were highlighted in the resulting analysis.

This suggests that rovers on Mars equipped with infrared spectrometers, like NASA’s Perseverance and Curiosity, should be able to detect biosignatures even if they are preserved in gypsum.

Connor hopes that future tests can shed light on how other minerals affect biosignature detection, giving researchers the best possible opportunity to find signs of organic matter on Mars.

This story is republished courtesy of the Natural History Museum. Read the original story here.