Mars has been the major playground to find extra-terrestrial life and is indeed an obsession for astrophysicists. Many research and discoveries so far have suggested life forms existed on the planet eons ago, at least on a microbial level. Now, a sample received by the NASA Curiosity rover has further provided evidence for this hypothesis.
Finding Life On Mars
NASA Curiosity rover has sent back chemical compounds from the Red Planet that support the theory of microbial life existing on the planet billions of years ago. The chemical compounds, known as thiophenes, are present in the soil sample from Mars. Thiophenes can be linked to life Mars.
Washington State University astrobiologist Dirk Schulze-Makuch and Jacob Heinz with the Technische Universität in Berlin have published a paper in Astrobiology regarding the thiophenes. Essentially, they are treated as an ancient biosignature because of their organic structure and the paper suggests that the presence of thiophenes in the Martian soil is linked to the existence of microbial life.
Furthermore, the published research notes that bacteria might be the reason for the thiophenes found on Mars through a biological process. These remnants have now been dug out of Mars' surface and further researched through the bacteria-catalyzed biological process.
How Valid Is It
The research paper has certainly found the presence of ancient bacteria, however, there are still many other aspects to look into. The researchers themselves state that there needs a biochemical link with valid proof.
"We identified several biological pathways for thiophenes that seem more likely than chemical ones, but we still need proof," Dirk Schulze-Makuch said to Phys.org paper. "If you find thiophenes on Earth, then you would think they are biological, but on Mars, of course, the bar to prove that has to be quite a bit higher."
One should note that many chemical pathways can create thiophenes and even their breakdown by bacteria. What's more, the ring-like molecular structure consists of carbon and sulfur atoms, making it a bio-essential element for life on Earth. Thiophenes are found in crude oil and mushrooms on Earth.
At the same time, it can be created even without microorganisms. Take for instance a meteor impact. It can also create an abiotic synthesis of thiophenes, even without any involvement of life forms.
Researching For Life On Mars
For now, a conclusive decision has yet to be made. This is because the Curiosity Rover employs a technique that breaks larger molecules up into components, which is what the scientists are trying to analyze. They are still experimenting with the thiophenes molecules to determine if they were processed by ancient bacteria or if it was abiotic in nature.
The actual proof will require live samples from Mars, which can be gathered only with astronaut visits. "I think the proof will really require that we actually send people there, and an astronaut looks through a microscope and sees a moving microbe," said Schulze-Makuch.