Rare Meteorites Found on Earth are from Mars, Curiosity Rover Confirms

Image: NASA

Some meteorites that drop in on Earth come from Mars.
We have suspected this for years, but this week, NASA's Curiosity rover confirmed their origin.


Using Sample Analysis at Mars (SAM) instrument — a highly sophisticated onboard chemistry lab that can conduct hundreds of the same experiments we do on Earth — Curiosity rover found two forms of argon, a noble gas that doesn't react to other compounds. This is an important gas because it tells the straightforward history of Mars, which was once a wet planet similar to Earth.
While argon exists throughout our solar system, on Mars, the ratio of heavy to light argon is skewed due to the loss of its atmosphere over billions of years. This fundamentally changed it into the cold, desert-like planet that exists today.


Modern Mars is filled with the heavy form, Argon 38. The lighter form, Argon 36, rose to the top where it then easily escaped. In a sense, Curiosity uncovered the planet's hidden signature by pinning down the ratio of these two forms at 4:2. To put that into context, NASA's Viking landers estimated the planet's atmospheric value to be in the range of 4:7.


"We really nailed it," said lead study author Sushil Atreya of the University of Michigan, Ann Arbor, who published the work in the journal Geophysical Research Letters. "This direct reading from Mars settles the case with all Martian meteorites," he said.br />

Out of the tens of thousands of known meteorites to slam into Earth, less than 50 have been identified with Mars origins.


The study appears in Geophysical Research Letters, a journal of the American Geophysical Union.

Mean while back on the planet Earth: Professor Steven Benner "Life on Earth came from elements that arrived from Mars on a Martian meteorite,.”

An element believed to be crucial to the origin of life would only have been available on the surface of the Red Planet, it is claimed. Geochemist Professor Steven Benner outlined his theory that the “seeds” of life probably arrived on Earth in meteorites blasted off Mars by impacts or volcanic eruptions.

All living things are made from organic matter, but simply adding energy to organic molecules will not create life. Instead, left to themselves, organic molecules become something more like tar or asphalt, said Prof Benner told the conference. He described the oxidised mineral form of the element molybdenum, believed to be a catalyst that fostered the development of organic molecules into the first living structures.

“It’s only when molybdenum becomes highly oxidised that it is able to influence how early life formed,” said Prof Benner, from The Westheimer Institute for Science and Technology in the USA. “This form of molybdenum couldn’t have been available on Earth at the time life first began, because three billion years ago the surface of the Earth had very little oxygen, but Mars did. “It’s yet another piece of evidence which makes it more likely life came to Earth on a Martian meteorite, rather than starting on this planet.”

He added: “Certain elements seem able to control the propensity of organic materials to turn to tar, particularly boron and molybdenum, so we believe that minerals containing both were fundamental to life first starting. “Analysis of a Martian meteorite recently showed that there was boron on Mars; we now believe that the oxidised form of molybdenum was there too.”

Study: Life On Earth May Have Started On Mars American Voices • Opinion • ISSUE 49•36 • Sep 3, 2013 5315337According to scientist Steven Benner, conditions on Mars 3 billion years ago were more conducive than those on Earth to creating one of the earliest molecules of life, RNA, and that meteorites may have transported these molecules to Earth’s surface. What do you think?

2010: Proof of Martian Life in the Past from Martian Meteorites

Picture: A close-up of the "colony of martian bacteria" revealed though a microscope in the Nakhla meteorite. (NASA)

Final proof that Mars has bred life will be confirmed this year, leading NASA experts believe. The historic discovery will come not on Mars itself but from chunks of the red planet here on Earth.

David McKay, chief of astrobiology at NASA's Johnson Space Centre in Houston, says powerful new microscopes and other instruments will establish whether features in martian meteorites are alien fossils.

He says evidence for life in the space rocks could have been claimed by the UK if British scientists had used readily-available electron microscopes. Instead, images of colonies of martian bacteria were collected by American scientists.

The NASA team is already convinced that colonies of micro-organisms are visible inside three martian rocks that landed on Earth. If so, this would have profound implications for our understanding of life in the universe.

Two of the meteorites - ALH84001 and Yamato 593 - were found in the Antarctic by American and Japanese scientists after they lay in the icy desert for thousands of years.

But of special interest is a meteorite that fell in many chunks at Nakhla, Egypt, in 1911. Most of the fragments ended up in London's Natural History Museum.

The stones are known to be from Mars because gases trapped inside them match those in rocks examined by probes on the red planet. They were blasted out of its surface by asteroid impacts and then drifted around the solar system for millions of years before falling to earth.

One of the new instruments that will analyse the meteorite will bombard it with a stream of ions to check whether features are geological or biological.

The NASA team believes a planet-wide network of micro-organisms came to life underground on Mars 3.6 billion years ago when the planet was much warmer and wetter with a much thicker atmosphere. Simple life was developing on Earth around the same time.

McKay says it is remarkable that some of the most striking new evidence for life on Mars has been sitting in London for nearly 100 years.

He told the website Spaceflight Now that if British researchers had examined their Nakhla meteorite with readily available electron microscopes and other tools like those used by the U.S. team, the new evidence for life on Mars could have been a British discovery, rather than an American one.

He added: "We do not yet believe that we have rigorously proven there is - or was - life on Mars. But we do believe that we are very, very close to proving there is or has been life there."