CAPE CANAVERAL, Fla. — A 4 billion-year-old meteorite from Mars that triggered a splash right here on Earth many years in the past comprises no proof of historic, primitive Martian life in any case, scientists reported Thursday.
In 1996, a NASA-led group introduced that natural compounds in the rock appeared to have been left by residing creatures. Other scientists have been skeptical and researchers chipped away at that premise over the many years, most not too long ago by a group led by the Carnegie Institution for Science’s Andrew Steele.
Tiny samples from the meteorite present the carbon-rich compounds are literally the consequence of water — almost definitely salty, or briny, water — flowing over the rock for a protracted interval, Steele stated. The findings seem in the journal Science.
During Mars’ moist and early previous, at the very least two impacts occurred close to the rock, heating the planet’s surrounding floor, earlier than a 3rd influence bounced it off the crimson planet and into area hundreds of thousands of years in the past. The 4-pound rock was discovered in Antarctica in 1984.
Groundwater shifting via the cracks in the rock, whereas it was nonetheless on Mars, shaped the tiny globs of carbon which might be current, in keeping with the researchers. The identical factor can occur on Earth and will assist clarify the presence of methane in Mars’ environment, they stated.
But two scientists who took half in the unique study took challenge with these newest findings, calling them “disappointing.” In a shared e mail, they stated they stand by their 1996 observations.
“While the data presented incrementally adds to our knowledge of (the meteorite), the interpretation is hardly novel, nor is it supported by the research,” wrote Kathie Thomas-Keprta and Simon Clemett, astromaterial researchers at NASA’s Johnson Space Center in Houston.
“Unsupported speculation does nothing to resolve the conundrum surrounding the origin of organic matter” in the meteorite, they added.
According to Steele, advances in know-how made his group’s new findings doable.
He counseled the measurements by the unique researchers and famous that their life-claiming speculation “was a reasonable interpretation” on the time. He stated he and his group — which incorporates NASA, German and British scientists — took care to current their outcomes “for what they are, which is a very exciting discovery about Mars and not a study to disprove” the unique premise.
This discovering “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 stated in an e mail, referring to Saturn and Jupiter’s moons with subsurface oceans.
The solely strategy to show whether or not Mars ever had or nonetheless has microbial life, in keeping with Steele, is to convey samples to Earth for evaluation. NASA’s Perseverance Mars rover already has collected six samples for return to Earth in a decade or so; three dozen samples are desired.
Millions of years after drifting via area, the meteorite landed on an icefield in Antarctica 1000’s of years in the past. The small gray-green fragment bought its title — Allan Hills 84001 — from the hills the place it was discovered.
Just this week, a bit of this meteorite was used in a first-of-its-kind experiment aboard the International Space Station. A mini scanning electron microscope examined the pattern; Thomas-Keprta operated it remotely from Houston. Researchers hope to make use of the microscope to research geologic samples in area — on the moon in the future, for instance — and particles that would destroy station gear or endanger astronauts.