In Major Find, NASA Discovers Signs Of Possible Life On Mars

The "oh my gosh" moment in the exploration of Mars has come: Scientists have announced not one, but two pieces of evidence that strongly suggest that the Red planet could be harboring life.

On Tuesday, NASA announced that its Mars rover Curiosity has found carbon-containing compounds in samples drilled out of an ancient rock. It marked the first time organic compounds – the building blocks for life – have been detected on the surface of Mars.

Moreover, the rover also found spurts of methane gas in the Martian atmosphere. Methane is a chemical produced either by living things or by 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., announced during a webcast press conference at the American Geophysical Union conference in San Francisco.

"The probability of any of these things being sources (from life) ... we just have to respect that it is a possibility," he added.

The latest findings marked a major turning point in the exploration of Mars. Just a year ago, NASA's Curiosity rover reported that after eight months of searching it had not found evidence of methane gas on Mars, all but dashing hopes that organisms might be living there now.

Despite its negative findings, the Curiosity rover continued to take samples of the Martian air. Finally in November 2013, according to NASA, the rover suddenly detected the presence of a large amount of methane around it which lasted for 60 days before vanishing.

The methane detections by Curiosity appeared to confirm observations by Earth-based telescopes and Mars-orbiting spacecraft that found mysterious but fleeting plumes of methane on the surface of the planet.

Scientists said the presence of methane is significant because the gas cannot exist for long in the harsh Martian atmosphere, which means that the detected methane must have been created just recently.

They said the methane could have been produced by geological process or could be a product of life in the form of microbes which release methane as a waste product.

Even if it turns out that methane's origin is geological, it would still suggest that the gas is coming from hydrothermal systems that could be prime locations to search for signs of life, the scientists said.

As for the organic molecules found by Curiosity, they showed up in a mudstone nicknamed Cumberland which the rover drilled in May 2013.

According to NASA scientists, Curiosity's miniature chemistry laboratory detected significant amounts of the organic molecule chlorobenzene, which is not a naturally occurring compound on Earth.

"In part, Curiosity was built to explore for organics," Dr. Grotzinger said, "and we found them."

The organics in Mars could have been delivered by comets and asteroids crashing onto the surface or produced indigenously, scientists said. Wherever they came from, they face a tough life on Mars which is constantly bombarded by deadly cosmic rays, they added.

Last week, scientists disclosed that the crater where Curiosity now sits was once filled with water, with sediments building up over time to form a 5-km high mountain called Mount Sharp.

Right after it landed, Curiosity found that the planet most like Earth in the solar system had the right chemical ingredients and environmental conditions to support microbial life, fulfilling the primary goal of the mission.