Rocks collected on Mars by NASA’s Perseverance rover could hold vital clues about the planet’s watery past and even the possibility of ancient life.
However, to unlock these secrets, scientists need to bring the samples back to Earth for detailed study.
NASA hopes to retrieve these samples by 2033, though delays in the mission could push this timeline further.
During nearly five months in 2022, the Perseverance rover collected rock samples from an ancient riverbed in a dried-up lake within Jezero Crater.
These rocks, which were deposited by water billions of years ago, could reveal when and how long liquid water existed on Mars and whether the planet ever supported life.
David Shuster, a professor of Earth and planetary science at the University of California, Berkeley, and a member of NASA’s science team, emphasized the significance of these samples. “These rocks are the reason why our mission was launched,” he said.
“This is exactly what everyone was hoping to find, and we’ve accomplished it.”
The rocks collected from Jezero Crater are the first sedimentary rocks ever studied and collected from a planet other than Earth.
Sedimentary rocks are formed by the accumulation of sediments, often transported by water, and can contain clues about the environment in which they were formed. In this case, these rocks were laid down in a body of water that once filled the crater.
Tanja Bosak, a geobiologist at the Massachusetts Institute of Technology (MIT) and the lead author of the study, explained that these rock cores might be the oldest materials ever collected from an environment that could have supported life.
“When we bring them back to Earth, they can tell us so much about when, why, and for how long Mars contained liquid water, and whether some form of life could have existed there.”
Some of the collected samples contain fine-grained sediments, which are the best type of rock to preserve evidence of past microbial life. On Earth, similar rocks often contain organic molecules that are linked to biological activity.
Shuster highlighted the importance of liquid water, saying, “Liquid water is essential for life as we know it. These fine-grained rocks are the most likely to preserve signs of past biological activity.”
In July 2023, NASA announced that Perseverance had collected new rock samples from a site called Cheyava Falls, which might also contain evidence of past life on Mars. The rover’s instruments detected organic molecules in these rocks, which are often associated with fossilized microbial life on Earth.
Despite the promising findings, the scientists caution that the rover’s instruments might not be sensitive enough to detect all organic molecules in the samples. Therefore, bringing the rocks back to Earth, where they can be analyzed with more advanced tools, is crucial.
So far, Perseverance has collected 25 samples, including duplicates and atmospheric samples, with some deposited in a “cache” on the Martian surface as a backup. The remaining samples are still aboard the rover, awaiting retrieval.
The research team, including Shuster and Bosak, has already begun analyzing some of the collected rocks. They found that the samples include sandstone, mudstone, and other materials formed by water.
These findings provide valuable insights into the history of water on Mars, which is central to understanding whether the planet could have supported life.
Ultimately, the answers to these questions depend on bringing the samples back to Earth. In terrestrial laboratories, scientists can analyze the rocks in ways that are impossible with the rover’s equipment, potentially uncovering evidence of past life on Mars.
Shuster emphasized the importance of the mission, saying, “One of the most important goals in planetary science is to bring these samples back to Earth.” The insights gained could help answer the age-old question: Was there ever life on Mars?
