The Search for Life on Mars: Organic Molecules in Martian Meteorite Not From Aliens

Organic molecules found in a meteorite that hurtled to Earth from Mars were synthesized during interactions between water and rocks that occurred on the Red Planet about 4 billion years ago, according to new analysis led by Carnegie’s Andrew Steele and published by Science .

The meteorite, called Allan Hills (ALH) 84001, was discovered in the Antarctic in 1984 and is considered one of the oldest known projectiles to reach Earth from Mars.

For years, scientists have debated the origin story for the organic carbon found in the Allan Hills 84001 meteorite, with possibilities including various abiotic process related to volcanic activity, impact events on Mars, or hydrological exposure, as well as potentially the remnants of ancient life forms on Mars or contamination from its crash landing on Earth.

The Steele-led team, which also included Carnegie’s Larry Nittler, Jianhua Wang, Pamela Conrad, Suzy Vitale, and Vincent Riggi as well as researchers from GFZ German Research Centre for Geosciences, Free University of Berlin, NASA Johnson Space Center, NASA Ames Research Center, and Rensselaer Polytechnic Institute, used a variety of sophisticated sample preparation and analysis techniques—including co-located nanoscale imaging, isotopic analysis, and spectroscopy—to reveal the origin of organic molecules in the Allan Hills 84001 meteorite.

One, called serpentinization, occurs when iron- or magnesium-rich igneous rocks chemically interact with circulating water, changing their mineralogy and producing hydrogen in the process.

It is unclear whether these processes were induced by surrounding aqueous conditions simultaneously or sequentially, but the evidence indicates that the interactions between water and rocks did not occur over a prolonged period.

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