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Organic carbon found on mars rocks is not life, new study says
Baku, May 25 (AZERTAC). Since the Viking landers’ footpads touched down on Mars, scientists have been searching for complex carbon molecules there, which on this planet are the building blocks of all life. They’ve found some examples in meteorites purported to come from the Red Planet, but debate persists about the origin of those rocks, let alone the carbon signatures inside them, which some have (controversially) argued could indicate life. Now a new study says the rocks in question are from Mars, but the carbon molecules are not relics of extraterrestrial life.
This new study sheds more light on Mars’ carbon cycle, suggesting that abiotic (not-life) sources of reduced carbon are actually pretty common. This will help set baselines for future life-hunting experiments.
Scientists led by Andrew Steele at the Carnegie Institution studied 11 meteorites from Mars, whose ages span 4.2 billion years. They even looked at the very recent Tissint meteorite, which fell in Morocco last summer and chunks of which were up for sale recently.
Steele and colleagues from four other countries examined the rocks with a suite of methods, including Raman spectroscopy, to determine the molecular structures. Ten of the rocks contained large carbon molecules, and at least some of those are indigenous to the rocks, meaning they didn’t come from Earth or other possible sources of contamination. It turns out the compounds originated in volcanic processes on our neighbor planet, not ancient microbes or other forms of life.
As silicate lava flows crystallized, carbon compounds interacted with oxide compounds and solidified. These compounds, which in one case included polycyclic aromatic hydrocarbons, are distributed throughout the rocks, Steele and colleagues report. This indicates that Mars has been completing organic chemistry on its own, probably for most of its existence.