NASA’s Perseverance Rover finds organic molecules on Mars
NASA’s Perseverance rover, currently exploring Mars’ Jezero crater, has discovered carbon-based molecules that could indicate ancient life on the Red Planet. These findings, reported last summer, were made using SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals), an advanced instrument that can identify potential organic compounds. While the discovery has raised hopes within the scientific community, questions remain about its accuracy as researchers consider alternative explanations for the data.
Detection of organic molecules and its challenges
The SHERLOC instrument uses two techniques: ultraviolet luminescence and Raman spectroscopy. Dr. Ken Farley, project scientist for the Perseverance mission, explained that SHERLOC can detect organic material that may be present in the Martian environment. Although luminescence is very sensitive, it lacks specificity because non-organic materials can also produce similar signals. Raman spectroscopy provides more accurate chemical fingerprints, but its sensitivity is limited. This combination allows researchers to make hypotheses about the presence of organic molecules, but uncertainties in the data make definitive conclusions difficult.
Possible alternative explanations
A study published in Science Advances stated that the detected signals could come from inorganic substances, such as defects in minerals such as phosphate and silicate or the presence of cesium ions. Dr. Eva Scheller, a planetary scientist at MIT and co-author of the study, emphasized that multiple chemical compounds can produce similar spectral patterns. Such overlaps, known in spectroscopy as degeneracy, make it challenging to interpret data reliably. The original researchers also recognized these alternative explanations, underscoring the inherent difficulties of remote Mars analyses.
Implications and future research
While the presence of organic molecules may not confirm life, Jezero Crater’s history as an ancient lakebed increases the significance of the discovery. Both Farley and Scheller agree that a Mars Sample Return mission could provide the clarity needed to determine whether these compounds come from biological or abiotic processes. Until then, debates over the findings are expected to continue, illustrating the evolving nature of scientific research.
