Scientists have discovered a strange microbial cell-like structure inside a Martian meteorite, but they do not claim that this is evidence of life on Mars.
Researchers discovered a microscopic oval structure in the Martian meteorite Nachla, which fell to Earth in Egypt in 1911. While the appearance of this structure is intriguing, it is most likely formed by geological rather than biological processes, team members say.
"Consideration of possible biotic scenarios for the origin of the egg-shaped structure in Nakhla is currently not possible due to a lack of conclusive evidence," the scientists write in a new study published this month in the journal Astrobiology. "Thus, based on the available data that we obtained about the nature of this egg-shaped structure in Nakhla, we conclude that the most reasonable explanation for its origin is that it was formed through abiotic processes."
The structure is about 80 microns long and 60 microns wide, the researchers say, much larger than most terrestrial bacteria, but within the normal range for Earth's eukaryotic microorganisms (single-celled organisms that possess a nucleus and organelles). The research team is confident that the object is native to the sample and not the result of terrestrial pollution.
Scientists studied the structure using a number of different methods, including electron microscopy, X-ray diffraction analysis, and mass spectrometry. This study showed that the oval structure is composed of iron-rich clay and contains a number of other minerals.