Mars: Honing New Technique for Finding Signs of Life
For decades, people have dreamed of the possibility of life on Mars. And as technologies have advanced, astronomers have bolstered their efforts in searching for civilized superbeings, to no avail. Although we have yet to discover life on the Red Planet, scientists are now honing a new technique that may change the game.
Most experts looking for hints of life on Mars search for water, with many unmanned probes from NASA and the European Space Agency (ESA) dedicated to the task in recent years. One study published in March even found that billions of years ago Mars once held more water than the Arctic Ocean, losing most of it to space.
"There has been a tremendous amount of very exciting findings this year that Mars once contained actively flowing, low-saline, near-neutral-pH water - pretty much the type of water where you find life on Earth today," researcher Alison Olcott Marshall, from the University of Kansas (KU), said in a statement. "This has made people think that it's possible that life could have existed on Mars, although most researchers agree it's unlikely to exist today - at least on the surface - as conditions on the surface of Mars are incredibly harsh."
So Olcott Marshall and her husband, Craig Marshall, associate professor of geology at KU, are working to improve the way scientists detect life on Mars. Specifically, they are investigating condensed aromatic carbon, which is thought to be a chemical signature of astrobiology.
"If we're going to identify life on Mars, it will likely be the fossil remnants of the chemicals once synthesized by life, and we hope our research helps strengthen the ability to evaluate the evidence collected on Mars," Craig explained.
According to their new study, published in the journal Philosophical Transactions of the Royal Society A, a technique known as Raman spectroscopy may be the key in finding carbonaceous materials, and therefore life, on our neighboring planet. By itself Raman spectroscopy can screen for carbonaceous material, however, it can't determine its source - thus the technology needs to be supplemented in order to determine if life exists on Mars.
"Raman spectroscopy works by impinging a laser on a sample so the molecules within that sample vibrate at diagnostic frequencies," Craig said. "Measuring those frequencies allows the identification of inorganic and organic materials. It's insufficient because however the carbonaceous material is made, it will be the same chemically and structurally, and thus Raman spectroscopy cannot determine the origin."
To solve this dilemma, the Marshalls also use gas chromatography/mass spectroscopy to supplement Raman spectroscopy and develop more conclusive evidence of ancient extraterrestrial life.
"Much like the search for ancient life on Earth, though, one strand of evidence is not, and should not be, conclusive," noted Alison. "This is a vast puzzle, and we want to make sure we are examining as many different pieces as we can."
Currently, the KU team is using Raman spectroscopy to analyze rocks from Earth that are similar to those on Mars.
"If you were to pick up a typical rock on Mars it would look quite different, chemically, from a typical rock here on Earth, not to mention the fact that it would be covered in rusty dust," the researcher added. "Previous research into how Raman spectroscopy would fare on Mars was mainly done on pure salts and minerals, often ones synthesized in a lab. We identified field sites on the Kansas-Oklahoma border with a chemical content more like what could be found on Mars, right down to the rusty dust, and we've been exploring how Raman spectroscopy fares in such an environment."
Although we have yet to uncover life at all on the Red Planet, this new technique could bring us one step closer to making that dream a reality.
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