Humankind has come one step closer to finding proof of life on Mars.
Nasa detected organic molecules on Mars, including chemicals widely considered building blocks for the origin of life on Earth.
The space agency’s rover Curiosity has been scouring Mars ever since it landed on the Red Planet in 2012.
It was in the Gale crater – where scientists believe conditions for supporting ancient life were favourable – that the robot discovered five new molecules.
The chemicals in the clay-rich sandstone are similar to the raw material that helped spur the development of life on Earth.
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However, the analysis performed by Curiosity cannot establish whether the organic compounds are linked to ancient life on Mars or non-biological processes, such as meteorites.
The experiment lead, Prof Amy Williams, an astrogeologist at the University of Florida, said: ‘We think we’re looking at organic matter that’s been preserved on Mars for 3.5bn years.
‘Is it life? We can’t tell, based on this information.
The 21 molecules discovered in total have survived hostile conditions on Earth’s neighbour planet.
Temperatures drop below -100C at night and the planet is blasted by radiation from the sun.
Williams said: ‘For a long time, we thought that all organic matter was going to be seriously degraded by that harsh radiation environment. It’s really exciting to see [that] large complex material can survive in the subsurface environment.’
The rover’s discoveries were confirmed with other instruments aboard the robot.
Its analysis recently detected compounds, including carbon that are linked to life.
The experiment also hinted at the presence of another compound that has a structure similar to the early forms of DNA.
‘There are several steps between what we found and DNA,” Williams said. ‘It is definitely a building block to how DNA is made now. But it is truly just the bricks, not the house. You can generate these molecules geologically.’
The scientists believe the observations from Curiosity could tie into discoveries from Nasa’s other on-duty Mars rover, Perseverance.
The European Space Agency’s Rosalind Franklin mission, which is scheduled to launch in 2028, will drill to a depth of 2 metres and be able to carry out more sophisticated tests on the compounds it finds.
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