© 2011 Darryl Pitt / Macovich Collection
A sample of a Mars rock from the Tissint meteorite fall, which dropped chunks of the Red Planet into the Morocco desert in July 2011.
Organic molecules - compounds that on Earth can be linked with life - encased within Martian meteorites now reveal biological activity on the Red Planet could not have formed these materials, researchers say.
Organic molecules are the carbon-based raw materials that building blocks of life such as proteins and DNA are made from.
These organic compounds have been detected in
meteorites from Mars that crashed on Earth before, but scientists have hotly debated what their origins are - they might be signs of life on the Red Planet, or merely contaminants that made their way into the rocks after they landed.
To help solve the mystery behind these organic molecules, researchers analyzed 11 Martian meteorites, including the new Tissint meteorite that fell into the Moroccan desert in 2011. Altogether, these rocks span 4.2 billion years of Martian history.
The investigators now reveal that organic molecules within these meteorites did originate
on Mars.
"Mars apparently has had organic carbon chemistry for a long time," study lead author Andrew Steele, a microbiologist at the Carnegie Institution of Washington, told SPACE.com.
However, these organic molecules do not appear biological in origin. "They formed from volcanic processes," Steele said.
Ten of the meteorites possessed complex hydrocarbons - compounds of carbon and hydrogen atoms - encased within grains of crystallized minerals that formed within cooling magma.
"When the minerals crystallized from the magma, they trapped carbon in them, and over time, organic compounds formed within these mineral bottles," Steele said.
