(CNN) – In search of extraterrestrial life, NASA’s Curiosity rover has been working for almost a decade to determine whether Mars is ever habitable.
New analysis of sediment samples collected by the rover revealed the presence of carbon, and the possible existence of ancient life on the red planet is a possible explanation for why it may be.
Carbon is the basis of all life on Earth, and the carbon cycle is a natural process of recycling carbon atoms. On our planet, carbon atoms go through a cycle as they travel from the atmosphere to Earth and back into the atmosphere. According to the National Oceanic and Atmospheric Administration (NOAA), most carbon is found in rocks and sediments, while the rest is found in the oceans, atmosphere and organisms.
Thus, carbon atoms – along with their recycling cycle – are tracers of biological activity on Earth. So they could be used to help researchers find out if there was life on ancient Mars.
When these atoms are measured inside another object, such as the Mars sediment, they can shed light on the planet’s carbon cycle, no matter when it occurs.
Learning more about the origin of this newly discovered Mars carbon may reveal the process of carbon rotation on Mars.
A study describing these findings was published in the journal Monday Processes of the National Academy of Sciences.
Secrets in the sediment
Curiosity landed on Gale Crater on Mars in August 2012. This 96-mile (154.5-kilometer) crater was discovered by Australian astronomer Walter F. Named after Gale, it was formed by a meteorite impact between 3,500 and 3.8 billion years ago. The Great Pit once contained a lake, now covering a mountain called Mount Sharp. The groove also includes layers of exposed ancient rock.
To get a closer look, the rover drilled between August 2012 and July 2021 to collect sediment samples across the crater. Curiosity then heated these 24 dust samples to about 1,562 degrees Fahrenheit (850 degrees Celsius) to separate the elements. This led to the samples being released into methane, which was then analyzed by another instrument in the rover’s arsenal to show the presence of stable isotopes of carbon or carbon atoms.
Some samples were low in carbon, others were enriched. Carbon has two stable isotopes, measured as carbon 12 or carbon 13.
“Most carbon-13-low samples are like samples taken from sediments 2.7 billion years old from Australia,” said Christopher H. Schmidt, lead author of the study and professor of geology at Pennsylvania State University. House said in a statement. Release.
“Those patterns were caused by biological processes when methane was consumed by ancient microbes, but we can not necessarily say that on Mars it is a planet formed with different materials and processes than Earth.”
In lakes on Earth, microorganisms like to grow in large colonies, which mainly form mats below the water surface.
3 possible origins of carbon
Different measurements of these carbon atoms may suggest three different things about ancient Mars. The origin of carbon may be due to cosmic dust, the ultraviolet decay of carbon dioxide, or the ultraviolet decay of biologically produced methane.
“Unlike conventional processes on Earth, all three scenarios are unusual,” the researchers said.
According to House, the first scene involves our entire solar system passing through a cloud of galactic dust, which happens once every 100 million years. The charged cloud of particles triggers cold events on the rocky planets.
“There’s not much dust in it,” House said. “It’s hard to see any of these deposition events on Earth’s record.”
But during such an event, the cosmic dust cloud may have lowered the temperature of ancient Mars, which may have contained liquid water. The planet is formed by glaciers, which are covered with dust. As the ice melts, the carbon-containing sediment layer remains stable. Although entirely possible, there is little evidence of the presence of glaciers in the Gale Crater, and research authors have suggested that more research is needed.
The second hypothesis involves the conversion of carbon dioxide on Mars into organic compounds such as formaldehyde due to ultraviolet radiation. This hypothesis requires further investigation.
The third way this carbon is produced has potential biological roots.
If this type of reduced carbon is measured on Earth, it will show the microbes’ intake of biologically produced methane. Curiosity previously discovered methane on Mars, Researchers can only guess if there were any methane large worms emanating from below the surface of Mars. If there were microbes on the surface of Mars like this, they would be consuming this methane.
Methane may have left a carbon path on the surface of Mars in contact with ultraviolet light.
Further drilling on the horizon
The Curiosity rover will return to the place where most of the samples were collected in a month, offering another opportunity to analyze the sediments from this mysterious place.
“This research has accomplished the long-term goal of exploring Mars,” House said. “It measures different carbon isotopes – one of the most important geological instruments – from the sediments of another habitable world, and does so after nine years of exploration.”