Within an ancient river delta, there may be fossil evidence of life on Mars.
Mars rovers may soon be given some new checkpoints to explore. Geologists say a specific area of an ancient river delta where NASA’s Perseverance rover is located on the rocky Red Planet may contain fossil evidence of extraterrestrial life.
While they don’t expect to find any bug-eyed, green aliens, they say that important organic compounds that suggest the presence of past life may be there, waiting to be uncovered.
The team of researchers behind the new study, published on October 7 in the journal Science, dissected the photographs taken byand revealed the ways water flowed on Mars billions of years ago.
Their analysis revealed spots on the dry orb that could hold the highly sought-after biosignature.
“We know that water was moving across the surface at one point in the past, but we don’t know the duration of this activity,” said study lead author Nicolas Mangold, a geologist at the University of Nantes in France.
NASA’s Perseverance and Jezero’s Tale
Once in space, Mars was not a dry and dangerous world. It was covered with fresh rivers and lakes, much like the earth. And where there is water, there can be life.
Huge bodies of H2O dried up ages ago as the blue planet’s delicate atmosphere formerly vanished. This changed the environment into the inhospitable land we know today.
Scientists have long been puzzled by the past existence of water on Mars. So NASA sent perseverance to traverse the planet in hopes of finding the fingerprints of life. More specifically, he sent the rover to a huge crater called Jezero.
Once flooded with water, Jezero Crater is believed to contain an ancient river delta—a delta that may contain signs of alien life.
Deltas are landforms formed by rock and sediments flowing from the course of a river. That stream often carried organic molecules and bacteria in its path, meaning that such material could easily accumulate in Jezero’s delta.
In other words, it may contain the fossilized building blocks of life.
With this in mind, the study team’s proposed points of interest for finding evidence of life on Mars are all linked to that delta. Initially, Mangold says, he hoped Perseverance would capture clear images of the spot, but unfortunately, Percy is a little too far from Old River for it.
“Despite our disappointment,” he said, “we tried to look at Delta from afar using our best cameras, and it produced really amazing results.”
clues from kodiaki
Amazingly, the researchers didn’t find the prized areas by simply analyzing Jezero’s main delta. They saw a butte, or rock mound, called a kodiak nearby. Kodiak is a part of the delta a little farther away.
“You can imagine that the delta extended a little bit to the south and east, then erosion removed some of the material,” Mangold said. “But Kodiak is miraculously preserved.”
The Kodiak serves as a geologic representation of the features of the main river delta. The stratigraphy, its rock layers, is relatively easy to see from afar, according to the researchers.
“By understanding the stratigraphy at Kodiak, it enables us to identify the deposits that are of most interest to life conservation,” Mangold said.
He described the team’s first glance at the photographs as a “shock”.
“The first image is actually [one] where we can see the boulders,” he said. “The delta fault … some big boulders can’t be found. It should be consistent.”
Those boulders, he said, mean the river delta of Jezero called a Gilbert-type delta. These are formed with strong water currents such as waves and tides, such as those found in a lake. Thus, the team believes that the river’s flow suddenly became more rapid over the course of its life.
“A big question for us,” Mangold said, “is to understand why this change in hydrological activity occurred, as it is probably a sign of climate change.”
Kodiak also gave information about how high the ancient body of water was. Mangold says it must have been about 8,202 feet (2,500 m) high, based on ridges of rocks in Butte. He says that this height varied over time, which is also consistent with the idea that the river moved into a lake.
“This kind of observation is really important,” he explained. “Because it shows that there was a lake in Jezero, there is no doubt about it …
In the end, all of this knowledge led Mangold’s team to isolate the places where the remains of life could be found—the deeper layers of the Kodiak that probably contain the remains of soil as well as grains of sand. These types of sediments are known to contain organic, life-sustaining molecules.
“Kodiak can’t be easily accessed by the rover because it’s a bit vertical,” Mangold said.
“But we have identified a few places on the main delta fault where we can reach similar types of layers. Those locations are our preferred targets for future rover travel.”