NASA discovery may be an early indication of life on Mars
The Curiosity rover has measured a spike of methane on the red planet - a gas that is associated with life back on Earth.
Monday 24 June 2019 15:41, UK
NASA may have uncovered an early indication of life on Mars after one of its rovers detected the largest amount of methane on the planet to date.
The vehicle - called Curiosity - measured the spike in an area known as the Gale Crater, although it was not equipped with the necessary instruments to determine the exact source of the gas.
Methane being found in significant quantities on other planets is notable because it is commonly associated with living things back on Earth.
The new measurement on Mars - 21 parts per billion units by volume (PPBV) - is the highest concentration the rover has recorded since landing in August 2012.
While still small compared with Earth, where it is about 1,800 PPBV, the find will certainly further pique the curiosity of scientists dedicated to monitoring the red planet for signs of life.
Paul Mahaffy, principal investigator for the NASA unit SAM (Sample Analysis at Mars), acknowledged that the limitations of Curiosity made it impossible to tell what the precise source of the methane was - that it could be "biology or geology, or even ancient and modern" - but it must have been released quite recently.
Methane is destroyed by solar radiation several hundred years after entering the atmosphere - which would suggest the newly discovered spike is from within that time frame - although there is the possibility that the gas could have been trapped underground for millions or billions of years and only just been released.
Previous discoveries have allowed researchers to document how the gas seems to rise and fall seasonally on Mars, but efforts to use the data to uncover possible life have been inconsistent so far.
While the latest detection is the biggest made by NASA to date, other agencies have been unable to come up with similarly significant readings during their time monitoring the planet.
The European Space Agency spacecraft Mars Express has only been able to match NASA measurements once before, and its Trace Gas Orbiter, which specialises in detection of methane, is yet to detect anything.