In puffs of gas from rocks more than 3 billion years old dug up by one of NASA's robotic explorers on Mars, scientists have identified several complex organic molecules - possible building blocks for ancient life.
It has been six years since the Mars rover Curiosity landed on the red planet, and now, the space vehicle has some news to share. About 95 percent of the methane in Earth's atmosphere is produced from biological activity, though the scientists said it is too soon to know if the Martian methane also is related to life.
Humayan is a professor of geochemistry at Florida State Univeristy and on staff at the FSU-headquartered National High Magnetic Field Laboratory.
The new results are detailed in two studies published Thursday in the journal Science. An incredible discovery because many forms of life have their origins from organic molecules. Curiosity has already indicated that water flowed in Gale crater which is the same place that the rover traced the organic matter billions of years ago. "That pessimistic possibility that has lurked as a fear at the back of everyone's minds may just have been changed forever".
What they can't say yet is whether there is, or ever was, life on the Red Planet. Thiophenes are the simplest sulphur-containing aromatic compounds (aromatic refers to how the molecules are bonded together) and it occurs with benzene in coal tar.
Although the surface of Mars is inhospitable today, there is clear evidence that in the distant past, the Martian climate allowed liquid water - an essential ingredient for life as we know it - to pool at the surface. Not exactly, but NASA describes it as a "good sign" in the quest for life on Mars.
"Curiosity has not determined the source of the organic molecules", Jen Eigenbrode, of NASA's Goddard Space Flight Centre, said.
"These results do not give us any evidence of life", stressed Eigenbrode.
Also, thanks to the longevity of the Curiosity rover, scientists have been able to observe a "breathing" of methane in the Martian atmosphere, with the amount increasing in the summer and reducing in the winter.
While this still does prove the existence of extraterrestrial life, it certainly is a step in the direction of potential life on Mars billions of years ago. According to scientists, this is the best piece of evidence that have been found so far. "Finding ancient organic molecules in the top five centimeters of rock that was deposited when Mars may have been habitable, bodes well for us to learn the story of organic molecules on Mars with future missions that will drill deeper". Supporting these claims were other organics, found near Curiosity's landing site, using a Sample Analysis at Mars (SAM) instrument. Sulfur may have helped protect the organics even when the rocks were exposed at the surface to radiation and bleach-like substances called perchlorates.