Molecules containing large chains of carbon and hydrogen--the building blocks of all life on Earth--have been the targets of missions to Mars from Viking to the present day. While these molecules have previously been found in meteorites from Mars, scientists have disagreed about how this organic carbon was formed and whether or not it came from Mars.
A new paper led by Carnegie's Andrew Steele provides strong evidence that this carbon did originate on Mars, although it is not biological. These findings give researchers insight into the chemical processes taking place on Mars and will help aid future quests for evidence of ancient or modern Martian life. The work is published May 24 in ScienceExpress.
There has been little agreement among scientists about the origin of the large carbon macromolecules detected in Martian meteorites. Theories about their origin include contamination from Earth or other meteorites, the results of chemical reactions on Mars, or that they are the remnants of ancient Martian biological life.
Steele's team examined samples from 11 Martian meteorites whose ages span about 4.2 billion years of Martian history. They detected large carbon compounds in 10 of them. The molecules were found inside of grains of crystallized minerals.
Using an array of sophisticated research techniques, the team was able to show that at least some of the macromolecules of carbon were indigenous to the meteorites themselves and not contamination from Earth.
Next the team looked at the carbon molecules in relation to other minerals in the meteorites to see what kinds of chemical processing these samples endured before arriving on Earth. The crystalline grains encasing the carbon compounds provided a window into how the carbon molecules were created. Their findings indicate that the carbon was created during volcanism on Mars and show that Mars has been doing organic chemistry for most of its history.
"These findings show that the storage of reduced carbon molecules on Mars occurred throughout the planet's history and might have been similar to processes that occurred on the ancient Earth," Steele said. "Understanding the genesis of these non-biological, carbon-containing macromolecules on Mars is crucial for developing future missions to detect evidence of life on our neighboring planet."
In a separate paper published by American Mineralogist, available online, Steele and his team studied a meteorite called Allan Hills 84001 that was reported to contain relicts of ancient biological life on Mars. The paper demonstrated that these supposed remnants could have been created by chemical reactions involving the graphite form of carbon, rather than biological processes. Both of these papers reveal a pool of reduced carbon on Mars and will help scientist involved in future Mars missions distinguish these non-biologically formed molecules from potential life.
Carnegie Institution: http://www.ciw.edu
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
The world's most sensitive dark matter detector is poised to join the hunt for WIMPs, the world's most elusive particles
Nearly 20,000 schools may be exposed to ground shaking
On the hundredth anniversary of the first fatal use of chemical weapons, we look back at the scientists who risked their lives to fight a new enemy
The ‘optical lattice’ device is now three times more accurate than previous incarnations
Researchers question the non-hazardous ranking of plastic, saying its environmental impacts are not subject to the same level of scrutiny as other pollutants.
Oklahoma geologists have documented strong links between increased seismic activity in the state and the injection into the ground of wastewater from oil and gas production, a state agency said on Tuesday.
Swallowing a sulfur-rich protoplanet could help explain two lingering mysteries in the story of Earth's formation
In a first-of-its-kind endeavor, electricity-starved Rwanda and the Democratic Republic of Congo are trying to get power from a lake—and avert catastrophe.It’s a Friday afternoon on the Rwandan side of Lake Kivu, and in what was once a quiet cove, a daring venture is taking shape.
The good news is that an eruption there is highly unlikely, but the bad news is that it would be huge
Flame-retardant fabrics normally degrade when washed, but a water-repelling coating could make your flame-proof suit or sofa self-cleaning