Breakthrough in search for Martian life as Curiosity finds organic matter and seasonal methane

NASA’s Curiosity rover has uncovered signatures of an environment on the red plant that may once have been habitable.

In two separate studies on data collected by the Mars rover over the last few years, scientists have identified an abundant source of organic matter in the ancient soil, and traced some of the planet’s atmospheric methane to its roots.

The findings could help to guide the search for ancient microbial life and improve our understanding of seasonal processes on Mars.

NASA revealed details on the latest findings in a press conference Thursday afternoon.

 

In two separate studies on data collected by the Curiosity rover over the last few years, scientists have identified an abundant source of organic matter in the ancient soil, and traced some of the planet’s atmospheric methane to its roots

While the announcement may not be the detection of life itself, the finding address factors that are ‘fundamental to our search for life,’ explained Paul Mahaffy, director of the Solar System Exploration Division at NASA’s Goddard Space Flight Center, during the conference.

The organic molecules identified in the Curiosity samples were found in rocks from an ancient lakebed, explained lead author and astrobiologist Dr Jennifer L. Eigenbrode.

‘Those organic molecules could have come from life,’ Eigenbrode said, ‘but we don’t know that there was ever life on Mars.

‘So those specific molecules are not evidence of life.’ 

Instead, these molecules could be traced to non-life sources, such as meteorites.

But, the researchers say the discovery is a ‘good sign’ for the red planet’s habitability. 

‘What were looking at here are a lot of layers that were put down in an ancient lake,’ Eigenbrode explained during the press conference, addressing the yet-unknown origins of the newly detected organic matter.

‘That lake had been there for a long periods of time – hundreds of thousands, maybe millions of years. Organic materials can come into that lake through rivers, they can be windblown in, or they can be formed in the lake itself through biology.

‘One source could be meteorites infalling, or rock forming processes that form organics on their own.

‘We don’t have enough information from the observations we’ve made to know what the source is, and how it got in there.’

‘The new findings reinforce our conclusions that there is Marian organic matter in the ancient sediments and they tell us about how the organic molecules are preserved in the rocks,’ Eigenbrode, lead author of one of the studies, told MailOnline in an email.

‘The detection of organic matter in rocks from an ancient habitable environment on Mars bode well for the future search for life on Mars.’

Using samples drilled by Curiosity from two sites in the Gale crater, the researchers detected several organic compounds in the Martian sediment.

The rover extracted and heated samples from Mojave and Confidence Hills – both of which are known to contain mudstones dating back roughly three billion years.

Molecules released after the samples were heated included some resembling organic-rich sedimentary rock found on Earth, according to the team, such as: thiophene, 2- and 3-methylthiophenes, methanethiol, and dimethylsulfide.

These molecules, however, differ by a single carbon sidechain, suggesting they may be fragments of larger organic molecules.

While the discovery does not mean Curiosity has found evidence of ancient life on Mars just yet, it is a promising step forward ahead of missions that plan to dig even deeper into the Martian soil.

‘Organic matter could come from life, but the presence of organics is not evidence for life since organics can also come from non-life processes,’ Eigenbrode told MailOnline.

The team looked at data from three Martian years (55 Earth months), revealing strong fluctuations that appear to follow a seasonal cycle. The authors say large amounts of methane is likely coming from beneath the surface, trapped in water-based crystals 

The team looked at data from three Martian years (55 Earth months), revealing strong fluctuations that appear to follow a seasonal cycle. The authors say large amounts of methane is likely coming from beneath the surface, trapped in water-based crystals 

‘We found organic matter in rocks exposed at the surface where the environment is very harsh and tends to break down organic matter.

‘Finding it in this harsh place means we might find better preserved organic matter in other places, particularly where it has not been exposed to lots of radiation.

‘To do this, we might drill deep, which is what ESA’s ExoMars rover plans to do.

‘Alternatively, we could look for outcrops that have been recently excavated by erosion or meteorite impacts. 

‘Perhaps NASA’s Mars2020 mission will have this opportunity and will cache samples for return to Earth.’

In addition to the discovery of organic materials, the Curiosity data also reveal new clues on the origins of Mars’ mysterious methane. 

While methane is known to exist in the scant Martian atmosphere, just how it got there has remained a mystery.

On Earth, this compound is linked to biological sources – meaning it’s closely tied to the presence of life.

But on Mars, scientists have proposed numerous other abiotic processes that could have given rise to the methane in question.

In one of the new studies, researchers used measurements of atmospheric methane captured by the Curiosity rover to better understand its origins.

The team looked at data from three Martian years (55 Earth months), revealing strong fluctuations that appear to follow a seasonal cycle.

Mars’ methane, the researchers found, ranges from about 0.24 to 0.65 parts per billion, peaking near the end of summer in the Northern hemisphere.

The latest findings could help to guide the search for ancient microbial life and improve our understanding of seasonal processes on Mars. NASA revealed details on the latest findings in a press conference Thursday afternoon

The latest findings could help to guide the search for ancient microbial life and improve our understanding of seasonal processes on Mars. NASA revealed details on the latest findings in a press conference Thursday afternoon

WHAT IS THE MARS CURIOSITY ROVER AND WHAT HAS IT ACHIEVED SO FAR?

The Mars Curiosity rover was initially launched from Cape Canaveral, an American Air Force station in Florida on November 26, 2011. 

After embarking on a 350 million mile (560 million km) journey, the £1.8 billion ($2.5 billion) research vehicle touched down only 1.5 miles (2.4 km) away from the earmarked landing spot.

After a successful landing on August 6th, 2012, the rover has travelled about 11 miles (18 km). 

It was launched on the Mars Science Laboratory (MSL) spacecraft and the rover constituted 23 per cent of the mass of the total mission. 

With 80 kg (180 lb) of scientific instruments on board, the rover weighs a total of 899 kg (1,982 lb) and is powered by a plutonium fuel source. 

The rover is 2.9 metres (9.5 ft) long by 2.7 metres (8.9 ft) wide by 2.2 metres (7.2 ft) in height. 

The Mars curiosity rover was initially intended to be a two-year mission to gather information to help answer if the planet could support life, has liquid water, study the climate and the geology of Mars an has since been active for more than 2,000  days

The Mars curiosity rover was initially intended to be a two-year mission to gather information to help answer if the planet could support life, has liquid water, study the climate and the geology of Mars an has since been active for more than 2,000  days

The rover was initially intended to be a two-year mission to gather information to help answer if the planet could support life, has liquid water, study the climate and the geology of Mars.  

Due to its success, the mission has been extended indefinitely and has now been active for over 2,000 days.

The rover has several scientific instruments on board, including the mastcam which consists of two cameras and can take high-resolution images and videos in real colour. 

So far on the journey of the car-sized robot it has encountered an ancient streambed where liquid water used to flow, not long after it also discovered that billions of years ago, a nearby area known as Yellowknife Bay was part of a lake that could have supported microbial life.

After ruling out several possible sources, the authors say the data suggest large amounts of Martian methane is likely coming from beneath the surface, trapped in water-based crystals called clathrates.

This gas is then released in varying amounts as the temperature changes across the seasons, rising through the cracks and fissures in the ground to escape to the atmosphere.

Each new piece of the puzzle is a crucial step in the search for Martian life.

‘The search for ancient life on Mars is really a search for the signatures of microbial life preserved in rocks,’ Eigenbrode says.

‘If life ever existed on Mars, we will increase our chances of finding its ancient signatures by finding better preserved organic matter.’ 

 



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