There is no sign of life in the Martian meteorite

By Marcia Dunn | Related press

CAPE CANAVERAL, Fla. – A 4-billion-year-old meteorite from Mars that caused a collision with Earth decades ago has no evidence of life on ancient primordial Mars, scientists reported on Thursday.

In 1996, a research team led by NASA reported that organic compounds in the rock appeared to be left over by living organisms. Other scientists are skeptical, and researchers have been breaking that premise for decades, most recently a team led by Andrew Steele of the Carnegie Institution for Science.

Steele said the small samples from the meteorite show that the carbon-rich compounds are actually the result of water – most likely salty, or milky – flowing through the rock over a long period of time. The findings appear in the journal Science.

During Mars’ wet and early past, at least two collisions occurred near the rock, heating the planet’s surrounding surface, before a third collision sent it away from the red planet and into space. millions of years ago. The 4-pound (2 kg) rock was found in Antarctica in 1984.

According to the researchers, groundwater moving through cracks in the rock, while it was on Mars, formed tiny carbon spheres. They say the same thing could happen on Earth, and could help explain the presence of methane in Mars’ atmosphere.

But the two scientists involved in the original study took issue with the latest findings, calling them “disappointing.” In a shared email, they said they tracked their 1996 observations.

Kathie Thomas-Keprta and Simon Clemett, astromaterials researchers at NASA’s Johnson Space Center in Houston, write: “Although the data presented increasingly add to our knowledge of (meteorites), but this interpretation is hardly novel, nor is it supported by research.

They added: “Unsupported speculation will not solve the conundrum surrounding the origin of organic matter.”

According to Steele, advances in technology have made his team’s new findings possible.

He commended the original researchers’ measurements and noted that their life hypothesis “was a reasonable explanation” at the time. He said he and his team – which includes NASA, German and British scientists – took care to present their results “in terms of what they are, which is a very exciting discovery about Mars rather than a study that disproves” the original premise.

The discovery “is huge for our understanding of how life started on this planet and helps refine the techniques we need to find life elsewhere on Mars, or Enceladus and Europa “, Steele said in an email, referring to Saturn and Jupiter’s moons with subsurface oceans.

According to Steele, the only way to prove whether Mars once had or still exists microbial life is to bring samples back to Earth for analysis. NASA’s Enduring Mars rover collected six samples to return to Earth in a decade or so; thirty samples are desired.

Millions of years after drifting in space, the meteorite landed on an Antarctic ice sheet thousands of years ago. The small blue-gray debris named – Allan Hills 84001 – from the hills where it was found.

Just this week, a fragment of this meteorite was used in one of its first experiments aboard the International Space Station. A mini scanning electron microscope examined the sample; Thomas-Keprta operated it remotely from Houston. The researchers hope to use the microscope to analyze geological patterns in space – on the moon someday, for example – and debris that could damage the station’s equipment or pose a danger dangerous for the astronauts.

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