NASA's Curiosity rover landed inside Mars's 96-mile-wide Gale Crater on August 6, 2012, and since then it has been probing the Red Planet's geology, climate and the question of whether or not it has ever supported microbial life. This is the most compelling evidence yet that this dry planet once held lakes filled with carbon-based compounds capable of sustaining life. The mission's Trace Gas Orbiter arrived at Mars in late 2016, and it's now collecting data that will let scientists map Mars's methane-and maybe even pinpoint its sources.
The findings do not answer if the compounds are remnants of past organisms, the product of chemical reactions with rocks, or if they were brought to the Red Planet by comets and other celestial debris, The Guardian reported.
That stuff is thought to be spread throughout the solar system, she said.
What has NASA found on Mars? "That's a big change", Dr Webster said.
Ever since, scientists have ardently hunted for Mars's missing carbon-or at least an explanation for its absence.
"There's three possible sources for the organic material", said astrobiologist Jennifer Eigenbrode of Nasa's Goddard Space Flight Center in Maryland. And life as we know it requires organic molecules to exist. "With these new findings, Mars is telling us to stay the course and keep searching for evidence of life", Thomas Zurbuchen, associate administrator for the Science Mission Directorate, said in a news release. But early into the rover's mission, researchers discovered that carbon-rich chemical reagents were leaking out of some of SAM's components, potentially contaminating nearby samples.
What's more, organic doesn't necessarily mean biological.
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In their new work the team checked to see what this restrictive process might have missed.
NASA's Curiosity Mars Rover snaps a self-portrait at a site called Vera Rubin Ridge on the Martian surface in February 2018 in this image obtained on June 7, 2018. "That gives me great hope because we can perhaps get past these surface environments that are so harsh and maybe [go] a little deeper and find better-preserved materials".
Webster explained that this is an exciting discovery because 99 percent of methane produced on earth has a biological origin, giving examples of rice paddies and termites. The 96-mile crater, named for Australian astronomer Walter F. Gale, was most likely formed by meteor impact between 3.5 to 3.8 billion years ago. The methane signal has been observed for almost 3 Martian years (nearly 6 Earth years), peaking each summer. Methane previously had been detected in Mars' atmosphere in large, unpredictable plumes. "It's like having a problem with your vehicle", he says.
Curiosity tested out the technique using it to drill a 2-inch-deep hole into a target called Duluth. For present life, some scientists say we should look below the surface, in soils or in caves, where there might be liquid water still flowing and organic compounds around.
Other scientists who did not take part in the research had mixed reviews on findings' significance in the search for life.
Scientists realized that they had to take a step back and try a more cautious, methodical approach. The rover has also detected methane in the Martian atmosphere.
Researchers can not yet say whether their discovery stems from life or a more mundane geological process. Eigenbrode says the analyzed rocks came from the bottom of what was once a lake at a time when Mars was a much warmer, wetter place. Such incremental progress is the whole point of NASA's Mars exploration program, Freissinet notes.