Nearly twenty years ago, a group of scientists at NASA’s Johnson Space Center published their findings that the the Allan Hills 84001 meteorite showed indications of ancient biogenic material; the paper caused quite a debate among the scientific community. The controversy has been opened once again, as a new analysis of the Yamato 000593 (Y000593) meteorite has revealed previously unknown features that might have been caused by ancient Martian life. The team was led by Lauren White from Jet Propulsion Laboratory and was published in the journal Astrobiology.
Y000593 was discovered in Antarctica in 2000. It has a mass of 13.7 kg (30 lbs) and came to Earth about 50,000 years ago. It is believed that the rock originated on Mars approximately 1.3 billion years ago. It is thought that a massive impact of the Martian surface dislodged the rock about 12 million years ago, and it spent over 11 million years in space until coming to Earth’s surface.
This recent analysis of Y000593 revealed that deep in the center of the meteorite, two sets of tunnels exist. One layer of tunnels has spherules between layers of carbonate and silicate rock, which are very similar to the Nakhla meteorite, which was recovered shortly after its impact in 1911 in Egypt. The other set consists of textured tunnels that curve through the rock. They appear to be consistent with previously studied tunnels that are caused by bacteria in basaltic glasses on Earth.
Additionally, the chemical composition of the meteorite is consistent with more aqueous conditions. As our current understanding of life requires liquid water to exist, this does seem to support the notion that ancient microbial life could have carved out the tunnels in the rocks and that Mars used to be incredibly dynamic.
The tunneling itself does not definitely prove that life once existed on Mars, but it does keep the conversation open for now. The research team admits that the tunneling could have been caused by abiotic forces or contamination from bacteria on Earth after impact, and may not have been formed by ancient Martian life millions of years ago. However, the team also states that these types of clues should not be ignored and this field of research should continue to be studied.
While analysis of samples from the Martian surface done by rovers have been great, scientists on Earth will need to examine actual samples from Mars in person to better understand the complexities of the Red Planet’s past.