Scientists confirm the presence of methane on Mars in major breakthrough in search for life on the red planet
- NASA’s Curiosity rover first detected a spike in the molecule on 15 June, 2013
- New study on data from Mars Express has found it detected this too, a day later
- Methane can be produced through both biological and geological processes
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Two missions observing the red planet have independently detected methane near Mars’ Gale Crater just one day apart.
Methane is said to be a promising clue in the search for life due to its links to biological activity on Earth.
NASA’s Curiosity rover first measured a ‘strong signal’ of the molecule on 15 June, 2013. But, some experts questioned the reliability of the discovery.
Now, a re-analysis of data collected by ESA’s Mars Express has found that the orbiting craft picked up on the methane ‘burp’ just one day after Curiosity, effectively confirming its presence.
NASA ’s Curiosity rover first measured a ‘strong signal’ of the molecule on 15 June, 2013. But, some experts questioned the reliability of the discovery. An ESA craft orbiting the red planet detected it a day later
The data show ‘one definite detection of about 15 parts per billion by volume of methane in the atmosphere,’ a day after Curiosity reported a spike of roughly 6 ppb, says lead author Marco Giuranna from the Institute for Space Astrophysics and Planetology.
‘Although parts per billion in general means a relatively small amount, it is quite remarkable for Mars – our measurement corresponds to an average of about 46 tonnes of methane that was present in the area of 49,000 square kilometers observed from our orbit,’ Giuranna said,
Methane can be produced through both biological and geological processes, so its presence is not a definitive sign of life.
But, it can point scientists in the right direction for where they should look.
While it was initially thought that the methane was coming from inside the crater, the new analysis changes this.
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Two missions observing the red planet have independently detected methane near Mars’ Gale Crater (shown) just one day apart
Methane can be produced through both biological and geological processes (illustrated above), so its presence is not a definitive sign of life. But, it can point scientists in the right direction for where they should look
Instead, scientists now suspect the methane is being released from beneath a layer of ice east of the crater.
‘We identified tectonic faults that might extend below a region proposed to contain shallow ice,’ says co -author Giuseppe Etiope from the National Institute of Geophysics and Volcanology in Rome.
‘Since permafrost is an excellent seal for methane, it is possible that the ice here could trap subsurface methane and release it episodically along the faults that break through this ice.
‘Remarkably, we saw that the atmospheric simulation and geological assessment, performed independently of each other, suggested the same region of provenance of methane.’
As of now, it’s not clear what’s behind the methane emissions.
A re-analysis of data collected by ESA’s Mars Express has found that the orbiting craft picked up on the methane ‘burp’ too
On Earth, methane is commonly released along fault lines and from natural gas fields in a process known as gas seepage.
There are also short-duration bursts, which can be seen, for example, in active mud volcanoes,
‘Our results support the idea that methane release on Mars might be characterized by small, transient geological events rather than a constantly replenishing global presence, but we also need to understand better how methane is removed from the atmosphere, and how to reconcile the Mars Express data with results from other missions,’ said co-author Frank Daerden from the Royal Belgian Institute for Space Aeronomy in Brussels.
‘We will re-analyse more of the data collected by our instrument in the past, while continuing our ongoing monitoring efforts, including coordinating some observations with the ExoMars Trace Gas Orbiter,’ Giuranna said.
WHAT EVIDENCE DO SCIENTISTS HAVE FOR LIFE ON MARS?
The search for life on other planets has captivated mankind for decades.
But the reality could be a little less like the Hollywood blockbusters, scientists have revealed.
They say if there was life on the red planet, it probably will present itself as fossilized bacteria – and have proposed a new way to look for it.
Here are the most promising signs of life so far –
Water
When looking for life on Mars, experts agree that water is key.
Although the planet is now rocky and barren with water locked up in polar ice caps there could have been water in the past.
In 2000, scientists first spotted evidence for the existence of water on Mars.
The Nasa Mars Global Surveyor found gullies that could have been created by flowing water.
The debate is ongoing as to whether these recurring slope lineae (RSL) could have been formed from water flow.
Meteorites
Earth has been hit by 34 meteorites from Mars, three of which are believed to have the potential to carry evidence of past life on the planet, writes Space.com.
In 1996, experts found a meteorite in Antarctica known as ALH 84001 that contained fossilised bacteria-like formations.
However, in 2012, experts concluded that this organic material had been formed by volcanic activity without the involvement of life.
Signs of Life
The first close-ups of the planet were taken by the 1964 Mariner 4 mission.
These initial images showed that Mars has landforms that could have been formed when the climate was much wetter and therefore home to life.
In 1975, the first Viking orbiter was launched and although inconclusive it paved the way for other landers.
Many rovers, orbiters and landers have now revealed evidence of water beneath the crust and even occasional precipitation.
Earlier this year, Nasa’s Curiosity rover found potential building blocks of life in an ancient Martian lakebed.
The organic molecules preserved in 3.5 billion-year-old bedrock in Gale Crater — believed to have once contained a shallow lake the size of Florida’s Lake Okeechobee — suggest conditions back then may have been conducive to life.
Future missions to Mars plan on bringing samples back to Earth to test them more thoroughly.
Methane
In 2018, Curiosity also confirmed sharp seasonal increases of methane in the Martian atmosphere.
Experts said the methane observations provide ‘one of the most compelling’ cases for present-day life.
Curiosity’s methane measurements occurred over four-and-a-half Earth years, covering parts of three Martian years.
Seasonal peaks were detected in late summer in the northern hemisphere and late winter in the southern hemisphere.
The magnitude of these seasonal peaks – by a factor of three – was far more than scientists expected.
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