NASA’s Mars Rover ‘Percy’ Finds First Signs of Past Life
Key Takeaways
- NASA’s Perseverance rover, nicknamed Percy, discovered organic molecules in a rock at the Cheyava Falls site on Mars.
- These organic molecules are carbon-based and could be potential building blocks of life, but this is not yet confirmed as a sign of life.
- Similar organic molecules were found in 2014 by the Curiosity rover, but the new discovery is raising fresh excitement.
- The rock sample showed white spots with black rims, resembling microbial formations found on Earth.
- Paul Byrne, a planetary scientist, urges caution, noting that these formations may also be a result of water-rock chemistry, not life.
- The discovery adds weight to the case for the Mars Sample Return (MSR) mission, which would bring the sample back to Earth for deeper study.
- Funding for MSR is uncertain, but the Perseverance rover continues to collect compelling samples in hopes of securing future funding.
MSSS/JPL-Caltech/NASA
The Search for Martian Life: NASA’s Perseverance Rover’s Discovery of Potential Signs of Life
NASA’s Perseverance rover (commonly referred to as “Percy”) made headlines in July 2024 when it uncovered its first possible signs of ancient life on Mars. This historic discovery took place at the Cheyava Falls site within the Jezero Crater, a once-dried lakebed. Percy drilled into a reddish rock and discovered organic molecules, sparking discussions across the scientific community.
However, excitement is tempered with caution. As Katie Stack Morgan, the deputy project scientist in charge of the Mars rover, noted:
“We’re not able to say that this is a sign of life. But this is the most compelling sample we’ve found yet.”
What Exactly Did Percy Find?
At the heart of this discovery are organic molecules, which are carbon-based compounds. On Earth, these molecules form the building blocks of life, but their presence on Mars doesn’t automatically mean that life once existed there. Still, it’s significant. These molecules were found in a sample taken from a rock at Cheyava Falls, a site named after a Grand Canyon feature.
Percy’s finding of white spots with black rims—compared to a tricolored leopard spot by Stack Morgan—adds another layer of intrigue. Instruments onboard Percy confirmed that the rims of these spots contained iron phosphate. On Earth, similar formations have been linked to ancient microbial life, as the chemical reactions forming these rings could potentially serve as an energy source for microbes.
Table 1: Organic Molecule Discovery Timeline on Mars
| Year | Rover | Discovery Location | Significance |
|---|---|---|---|
| 2014 | Curiosity | Gale Crater | Detected the first organic molecules on Mars |
| 2024 | Perseverance | Cheyava Falls (Jezero Crater) | Found organic molecules and formations resembling microbial life |
Why This Discovery Matters
Since its landing in Jezero Crater three years ago, Percy has been tasked with finding signs of ancient life. Though earlier searches proved challenging, this new discovery represents a significant step forward. Ken Farley, project scientist at the California Institute of Technology, introduced Percy’s finding at the 10th International Conference on Mars held in Pasadena, California, on July 25, 2024.
Percy’s discovery isn’t just about the presence of carbon-based molecules; it’s about what they might represent. Paul Byrne, a planetary scientist at Washington University in St. Louis, acknowledges the possibility that these molecules might be signs of life but stresses caution. He suggests:
“Could this truly be a signature of life? Yes. And if it is, then it really is the kind of society-altering discovery that the discovery of truly extraterrestrial life would be.”
Table 2: Key Instruments Used by Perseverance
| Instrument Name | Function |
|---|---|
| SHERLOC | Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals; used to find signs of life |
| PIXL | Planetary Instrument for X-ray Lithochemistry; analyzes chemical elements |
| SuperCam | Uses lasers to identify the chemical composition of rocks and soil on Mars |
| Mastcam-Z | A powerful camera system used to capture high-definition images of Mars’ surface |
What Could These Spots Mean?
One of the most captivating aspects of Percy’s discovery is the spotted rock it uncovered at Cheyava Falls. The spots have black rims, composed of iron phosphate. While not definitive proof of past life, on Earth, formations like these are often linked to ancient microbial life. According to Katie Stack Morgan, rings of iron phosphate can be an energy source for microbes. Still, she emphasizes caution, stating:
“They don’t require life, but based on our experience with similar things on Earth, there is a possibility that life could have been involved.”
The discovery becomes even more complicated with the volcanic features Percy found in the rock. There are white veins of calcium sulfate. Calcium sulfate is a material often seen in areas affected by volcanic activity. Percy also found small crystals of olivine.
Olivine is a type of mineral that forms when volcanic magma cools and hardens. This discovery makes the rock’s structure even more mysterious.
The combination of organic molecules, iron phosphate spots, and volcanic features in the same sample raises questions about the rock’s history. According to Stack Morgan, these seemingly conflicting features might point to different formation processes. Understanding how the rock formed could offer clues about whether it had the right temperatures and conditions to support life in the past.
Despite this uncertainty, the discovery has rekindled excitement within the scientific community. While the evidence is not conclusive, it’s the closest scientists have come to finding potential biosignatures on Mars. Still, as Paul Byrne puts it, the discovery could be nothing more than an example of water-rock chemistry, which is why caution is essential.
With this newfound discovery, the attention now shifts to the Mars Sample Return (MSR) mission. MSR aims to bring samples collected by Percy back to Earth, where scientists can study them with advanced technology. The issue, however, is that funding for MSR is currently on hold.
Stack Morgan and her team continue to push forward, collecting samples and hoping that this discovery strengthens the case for the mission. The rock samples collected so far, particularly the one from Cheyava Falls, could hold answers that we cannot uncover with the instruments onboard Perseverance alone.
Why the Mars Sample Return is Crucial
Despite the exciting possibilities of Percy’s findings, it’s important to recognize the limitations of its instruments. While the rover has powerful tools, some questions can only be answered with more sophisticated instruments back on Earth. As Paul Byrne notes:
“The only way to find out for sure is to bring the rock home.”
Percy’s discovery shows that more research is necessary. It also shows how important MSR is. MSR stands for Mars Sample Return. This means bringing rocks and soil from Mars back to Earth so scientists can study them closely. Without MSR, we may not be able to prove if life exists or existed on Mars.