"With these new findings, Mars is telling us to stay the course and keep searching for evidence of life", Thomas Zurbuchen, NASA science director at agency headquarters, said in a statement. And life as we know it requires organic molecules to exist. Organic matter can be one of several things: a record detailing ancient life, a food source for life or something that exists in the place of life.
Curiosity also measured an unexpectedly large seasonal cycle in the low levels of atmospheric methane. Previous research had seen evidence for sporadic methane plumes on Mars, but never seasonally recurring events. Mars2020 will shed light on the organic molecules-and prepare a sample that some future mission could bring back to Earth. Also pleasing is that the presence of chlorine and sulphur, which both preserve organics, suggests the presence of many more deposits from which to learn more about Mars' past and possible ecosystems. While commonly associated with life, organic molecules also can be created by non-biological processes and are not necessarily indicators of life.
The discoveries, reported today in two papers in the journal Science, while not evidence of life, provide more tantalising clues about what's happening on Mars, for future missions to investigate.
Maybe even billions of years - the Gale crater, named after Australian astronomer Walter F. Gale, is up to 3.8 billion years old, and may have once held a lake.
The sediments, analysed by the SAM instrument on Curiosity, come from just below the surface, where they have been shielded from most of the UV radiation that would break down organic molecules exposed on the surface.
Methane, the simplest organic molecule, ranges "between 0.24 to 0.65 parts per billion, peaking near the end of summer in the Northern hemisphere", said the report, based on three years of data.
158 migrants land ahead of visit by anti-immigrant Salvini
Salvini said holding centres for those awaiting deportation would be built so "they won't leave from morning till night". While Tria has been critical of the European Union , he is not been seen as an advocate for an exit from the eurozone.
The Curiosity rover, which has travelled 19.3 km since it landed in the Gale crater almost six years ago, detected a number of organic molecules in pieces of Martian mudstone it drilled from the lake bed and heated in its oven.
JPL's Christopher Webster, lead author on the study, said it's the first time Martian methane has shown a repeated pattern.
NASA's Curiosity rover has previously found organic matter on Mars.
They don't exactly roll off the tongue, but researchers believe that these are fragments of larger molecules that were present on Mars billions of years ago. But it is the preservation of the material that is important - if there is this much organic matter preserved close to the surface, then there should be even better protected material at greater depths.
Webster and his colleagues suspect that the methane comes from deep underground, and temperature swings on Mars's surface throttle its flow upward. The host of the session, assistant director of science for communications in NASA's Planetary Science Division Michelle Thaller, began by clearing up any rumors that the agency would announce that they had found alien life.
He and his colleagues think the methane is coming from underground.
In December 2012, the rover's two-year mission was extended indefinitely.