NASA's Mars Curiosity rover has detected carbon-containing compounds in samples drilled out of an ancient rock, the first detection of organics on the surface of Earth's nearby planet.
Curiosity also found spurts of methane gas in the atmosphere, which is a chemical that on Earth is tied to life, according to Reuters. Other studies, which could be beyond the rover's capabilities, are in order to figure out if the organic compounds and methane gas were produced by past or present life on Mars or from geochemical processes.
"We have had a major discovery. We have found organics on Mars," Curiosity lead scientist John Grotzinger, with the California Institute of Technology in Pasadena, Calif., said during a webcast press conference at a science meeting in San Francisco, according to Reuters.
"The probability of any of these things being sources (from life) we just have to respect that it is a possibility," Grotzinger added.
The rover picked up hints of organics in early chemical analysis of rocks in the Gale Crater, a 96-mile wide impact basin where Curiosity landed back in August 2012.
Earlier this month, scientists published a study showing that the crater was once filled with water and sediments built up over time to form three-mile high Mount Sharp.
After the rover landed, it found that the planet most like Earth in the solar system had the necessary chemical ingredients and environmental conditions needed to support microbial life, thus fulfilling the main goal of the mission, according to Reuters.
Curiosity co-investigator Chris Webster, with NASA Jet Propulsion Laboratory in Pasadena, California, said the methane detections were a huge surprise.
In 2013, scientists confirmed that after searching for eight months the rover found no detectable methane in the atmosphere around the Gael Crater.
Curioisty continued to take air samples and in November 2013 it hit pay dirt with a methane spike 10 times higher than background levels. The patch remained around the rover for 60 days until vanishing.
There is a chance the methane was produced around the rover and then dissipated in the wind, said Curiosity scientist Sushil Atreya, with the University of Michigan, Ann Arbor to Reuters.
The methane detections by the rover took place after a number of observations by Earth-based telescopes and Mars-orbiting spacecraft that discovered mysterious plumes of methane.
"We're really not in a position from these data to say one way or the other what the origin of the methane is," Atreya said.
"Because we are seeing signals here it's worth coming back and doing more work," Grotzinger added. The research was released at the American Geophysical Union conference. The methane study will be published in this week's issue of the journal Science.