Mud cracks suggest Mars once had Earth-like conditions, experts say

Is this proof Mars once had life? Odd patchwork of polygon-shaped mud cracks suggests Red Planet used to have Earth-like conditions 3.6 billion years ago, scientists say

  • NASA’s Curiosity rover has detected an unusual array of cracks on Mount Sharp
  • Sediments found here indicate that wet and dry cycles may once have occurred 

NASA’s Curiosity rover has spent 11 years searching far and wide for signs of life on Mars.

And now it has emerged that the car-sized robot may have found something.

In 2021, it detected an unusual array of polygon-shaped cracks within the soil that scientists now believe is evidence that the Red Planet once had Earth-like conditions that could have allowed microorganisms to survive 3.6 billion years ago.  

The mysterious mud cracks on the bed of an ancient lake hint that wet and dry cycles comparable to the seasons we experience on our planet today may have existed on Mars.   

Such cycles are vital for encouraging the formation of carbon-based ‘polymers’ – known as the building blocks of organic compounds and even DNA. 

NASA’s Curiosity rover has detected an unusual array of polygon-shaped cracks on Mount Sharp, Mars


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 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. 

‘This is the first tangible evidence we’ve seen that the ancient climate of Mars had such regular, Earth-like wet-dry cycles,’ said lead author William Rapin of France’s Institut de Recherche en Astrophysique et Planétologie. 

‘But even more important is that wet-dry cycles are helpful – maybe even required – for the molecular evolution that could lead to life.’

Curiosity was launched from Florida’s Cape Canaveral in 2011 as part of a two-year mission to gather information on whether Mars could support life.

Due to its success, the mission was extended indefinitely, with the mud cracks detected just two years ago after the rover ascended the 15,840ft-high Mount Sharp.

These were found at the site of an ancient lake, wedged between a clay-rich sediment layer and a more salty sulfite layer.

The two contrasting layers suggest that wet and dry cycles once occurred, as clay usually arises in moist conditions and sulfites generally form as any water dries up.

It is believed the unusual cracks also formed in the midst of this, transforming from dried up ‘t-junctions’ to hexagonal shapes due to water exposure. 

Long chains of carbon-based molecules known as polymers may have formed too, which are largely known to be the chemical building blocks of life.

In 2017, similar cracks were also discovered at a nearby rock known as  the ‘Old Soaker’. 

It’s not clear why these cycles may have stopped, though some scientists believe that temperatures were far warmer than they are today, facilitating a flow of liquid water. 

‘This paper expands the kind of discoveries Curiosity has made,’ said Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Southern California. 

Sediments found here indicate that seasonal wet and dry cycles may once have occurred

The Martian Curiosity rover (pictured) was launched from Cape Canaveral in 2011 as part of a two-year mission to gather information on whether the planet could support life

Unlike Earth, Mars doesn’t host any tectonic plates meaning that ancient sediment is better preserved

‘Over 11 years, we’ve found ample evidence that ancient Mars could have supported microbial life. 

‘Now, the mission has found evidence of conditions that may have promoted the origin of life, too.’

Unlike Earth, Mars isn’t home to any tectonic plates, meaning that ancient sediments are not buried far below the surface and are instead quite well-preserved. 

As a result, scientists believe that prehistoric biology and geology can be examined more thoroughly.  

Mr Rapin added: ‘It’s pretty lucky of us to have a planet like Mars nearby that still holds a memory of the natural processes which may have led to life.’ 


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 –


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.


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

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.


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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