Samples of Martian rock collected by NASA’s Curiosity Mars rover show signs of key ingredients for life as we know it on Earth.
The venerable Curiosity Rover perforated samples of Gale crater, the site of an ancient lake on Mars. Using these samples, scientists were able, for the first time, to measure the total amount of organic carbon in Martian rocks, according to a NASA statement (opens in a new tab).
Organic carbon, which is carbon attached to a hydrogen atom, is a prerequisite for organic molecules created and used by all known forms of life. However, organic carbon can also come from non-living sources, such as meteorites and volcanic eruptions. Although previous studies have detected smaller amounts of organic carbon in Martian rock samples, the new measurements provide information on the total amount of carbon in organic compounds.
Related: The stunning Mars photos of the Curiosity rover show an old climate change
“Total organic carbon is one of several measures [or indices] which help us understand the amount of material available as a raw material for prebiotic chemistry and potentially biology, “said Jennifer Stern, lead author of the study and space scientist at NASA’s Goddard Space Flight Center in Greenbelt. Maryland, in the statement. “We found. at least 200 to 273 parts per million organic carbon. This is comparable to or even more so than the amount found in rocks in very low-lying habitats on Earth, such as parts of the Atacama Desert in South America, and more than has been detected in meteorites. of Mars “.
Today, Mars is not a suitable environment for life, but there is evidence to suggest that the Red Planet was more suitable. Earth-as billions of years ago, with a thicker atmosphere and liquid water on its surface, key ingredients for life as we know it on Earth.
Martian samples were collected from 3.5 billion-year-old mud rocks in the Gale Crater Formation in Yellowknife Bay, which Curiosity has been exploring since 2012. Scientists think the sediment formed through the physical and chemical weathering of volcanic rocks, before settling. at the bottom of the lake.
The rover analyzed the fragments using its Mars Sample Analysis (SAM) instrument, which uses high oxygen and heat to convert the organic carbon in the samples to carbon dioxide. From the amount of carbon dioxide produced, the instrument calculates how much organic carbon was in the original sample and indicates the exact proportion of isotopes, which helps scientists understand the carbon source, according to the statement. Isotopes are forms of the same chemical element that differ in the number of neutrons in their nuclei.
“In this case, the isotopic composition can only tell us what part of the total carbon is organic carbon and what part is mineral carbon,” Stern said. “While biology cannot be completely ruled out, isotopes cannot really be used to support a biological origin of this carbon, as the range overlaps with igneous (volcanic) carbon and meteoric organic material, which are more likely to be the source of this carbon. organic carbon “.
However, in addition to organic carbon, the researchers identified other signs that suggest Gale crater may be they have ever endured lifeincluding the presence of chemical energy sources and chemical compounds such as oxygen, nitrogen and sulfur and low acidity.
“Basically, this location would have provided a livable environment for life, if it had never been present,” Stern said in the statement.
His findings were published Monday (June 27) at the Proceedings of the National Academy of Sciences.
Follow Samantha Mathewson @ Sam_Ashley13. Follow us on Twitter @Spacedotcom and on Facebook.