Ancient Organic Matter Found on Mars Could Share Traits With “Building Blocks” of Life

NASA’s Curiosity rover has been patrolling the surface of Mars since 2012. But more than a decade later, the robot continues to make discoveries.

In a new article published in the journal Natural communications, Researchers have detailed the results of a new Curiosity experiment that identified organic molecules on the surface of Mars, including those considered essential to the origin of life on our planet.

The molecules could indicate that Mars also hosted life eons ago, but researchers warned they could also come from meteorite crash landings or geological processes.

“We think this is organic material that has been preserved on Mars for 3.5 billion years,” Amy Williams, an astrobiologist at the University of Florida and co-author of the study, said in a statement.

Williams, who worked on the Curiosity and Perseverance Mars Rover missions, added: “It’s really useful to have evidence that ancient organic matter is preserved, because it’s a way to assess the habitability of an environment. And if we want to look for evidence of life in the form of preserved organic carbon, this demonstrates that it’s possible.”

Ancient organic matter on Mars

Curiosity landed in Mars’ Gale Crater, an ancient lake bed. The robot carried out the experiment detailed in the new article in 2020, in the Glen Torridon crater region. This area is rich in clay, a strong indicator that the area once contained water. The region appears to have been dried and wet several times throughout the planet’s history. Clay deposits easily attach to and preserve organic compounds.

Inside the rover is a complex microlaboratory called Sample Analysis at Mars (SAM). The rover drills rock samples and pulverizes them into powder. The robot adds this powder to a cup of tetramethylammonium hydroxide (TMAH) solvent inside the SAM chamber, which breaks down the clay samples into their constituent volatile fragments.

According to NASA’s Jet Propulsion Laboratory, which led the project, there are only two such cups aboard the SAM, complicating the decision about which areas of Mars to sample.

The experiment released 21 different carbon-based molecules. Seven had never been detected on Mars before. A molecule called a nitrogen heterocycle resembles the chemical precursors to the nucleic acids DNA and RNA that are essential for life on Earth. This type of molecule has never been found on Mars.

Another was benzothiophene, a chemical that often reaches planets via meteorites. These meteorites may have played an important role in bringing the building blocks of life to the planets of the developing solar system.

“The same thing that fell on Mars from meteorites is what fell on Earth, and it likely provided the building blocks for life as we know it on our planet,” Williams said in the release.

Learn more: Resilient fungus could survive the journey to Mars – and perhaps other planets

Comparison of samples on Mars

The researchers compared their findings on Mars with samples taken from the Murchison meteorite, a four-billion-year-old rock that has been widely studied.

When the researchers added a sample of the meteorite to TMAH solvent on Earth, they recorded some of the same molecules observed on Mars, suggesting that the samples on the Red Planet may once have been even more complex organic compounds.

“We now know that there are large, complex organics preserved in the shallow subsurface of Mars, and this holds great promise for preserving large, complex organics that could be diagnostic of life,” Williams said.

Learn more: Giant spider web formations on Mars contain ancient evidence of the planet’s waterlogged past

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