Yesterday, NASA made the startling announcement that its scientists have uncovered the ‘clearest evidence’ yet for the existence of life on Mars.
Last year, NASA’s Perseverance rover discovered that a dry riverbed just north of the Martian equator is dotted with rusty circular markings known as ‘leopard spots’.
According to NASA administrator Sean Duffy, the space agency now believes these marks could have been left by ancient lifeforms which lived billions of years ago.
Now, scientists have revealed what these alien organisms might have looked like.
Any life that evolved on Mars would have had to contend with harsh radiation, weak gravity, and temperatures that can swing between 20°C (70°F) in the day and -153°C (-225°F) at night.
However, the scientists behind this groundbreaking research say that it is still possible for some forms of life to evolve.
If there were life on Mars, it would almost certainly consist of very simple microbial organisms like bacteria.
In the unlikely case that more complex life did evolve somewhere on the Red Planet, it would need to develop special adaptations to survive this impossibly harsh climate.
NASA has revealed the ‘clearest evidence’ yet for the existence of life on Mars, as it claims that ‘leopard spots’ on Martian rocks could have been created by ancient microbes
Scientists say that Mars’ Jezero Crater was once filled with water that would have been ‘clement’ for microbial life to develop. Pictured: AI-generated impression
What did NASA find on Mars?
While investigating a region known as the ‘Bright Angel’, NASA’s Perseverance rover spotted a group of unusual markings that resemble leopard spots.
Scientists call these spots ‘reaction fronts’, and they are points of contact where chemical and physical reactions have occurred in the past.
Critically, Perseverance’s on-board lab found that these spots contained two iron-rich minerals: Vivianite, which is found in decaying organic matter, and greigite, which is produced by microbes on Earth.
Dr Keyron Hickman-Lewis, an Earth scientist from Birkbeck, University of London and co-author of the NASA report, told Daily Mail: ‘The kinds of organic–mineral associations observed at Bright Angel that are reported in this paper are known to be generated by microbial life on Earth, and so it is a very promising observation to see something so similar on Mars.
‘Certainly, I think that this is the most compelling potential evidence of life on Mars found to date.’
The scientists can’t yet rule out that these spots could be caused by non-biological processes, and Dr Hickman-Lewis says that this is not a ‘smoking gun’.
However, after spending a year reviewing the evidence and looking for alternative explanations, the researchers are now confident enough to say that this could be a ‘biosignature’, an elusive sign which proves the existence of life.
These signs of life were found by the Perseverance rover in a region called ‘Bright Angel’. Researchers say that chemicals found in the leopard spots are produced by biological processes on Earth
Although Mars is now a barren desert, billions of years ago, it would have been covered with rivers and lakes that could have supported life
Dr Hickman-Lewis adds: ‘The Mars 2020 team does not use the term “potential biosignature” lightly.’
What would this life look like?
The potential signs of life were found in a region called Jezero Crater, an impact basin just north of the equator.
Although it is now a barren wasteland, billions of years ago, the Jezero Crater was filled with water that could have been home to life.
If life did exist in these waters, the most plausible explanation is that it was some sort of simple microorganism.
Dr Hickman-Lewis says: ‘The environment in which these potential biosignatures were found seems to be a low-temperature water-rich setting and therefore very clement for microbial life.’
In their paper, published in Nature, the researchers suggest that microbes could have fed on the naturally occurring carbon, sulphur, and phosphorus in the rocks.
These microbes would have then ‘excreted’ the minerals which we now see as leopard spots.
NASA Administrator Sean Duffy (center) revealed that a sample collected by Perseverance is the ‘clearest sign of life’ on Mars ever found in 30 years
The Jezero Crater, where the potential signs of life were found, was once a river delta. Observations from orbiting spacecraft show patterns of sediment that are similar to those made by rivers on Earth. Pictured: AI-generated impression
As microbes fed on the carbon, sulphur, and phosphorus in the rocks, they might have released iron-rich chemicals which permanently stained the rocks to leave ‘leopard spots’. Pictured: AI-generated impression
The conditions on the surface would have been incredibly harsh, but the researchers say that life still could have eked out a simple existence.
Dr Sanjeev Gupta, an Earth scientist from Imperial College London and member of the research team, told Daily Mail: ‘There was liquid water present at the surface at the time billions of years ago, so it was a habitable environment.
‘This would have been simple microbial life. We can say much more than that.’
Since we can only see the possible traces left behind by these microorganisms, it’s difficult to know what they might have looked like or how they behaved.
However, it is possible to make some very general predictions based on parallels from Earth.
Professor Michael Garrett, an astronomer from the University of Manchester and Director of Jodrell Bank Centre for Astrophysics who was not involved in the study, told Daily Mail: ‘Think of hardy bacteria, similar to terrestrial extremophiles that thrive in very salty, cold, or low-oxygen conditions here on Earth.
‘Good analogues are the microbial mats in very salty lakes or microbes that live kilometres underground in Earth’s crust or in the high desert in Chile.
‘These examples show us that life can be tough, minimalistic, and persistent even in places where surface conditions are brutal.’
Scientists say that the best parallels for what life might have looked like are the microbial mats that form in extremely salty lakes on Earth. Pictured: AI-generated impression
It is unlikely that more complex life could have evolved since Mars’ climate changed rapidly about a billion years after the first microbes could have appeared. This means complex organisms like animals probably didn’t have time to develop. Pictured: AI-generated impression
Could more complex life have evolved?
If these leopard spots really are biosignatures, then the researchers say it’s unlikely that they only existed in one place.
Perseverance is currently studying very ancient rocks outside of the Jezero Crater to look for signs of more widespread life.
However, it is extremely unlikely that more complex life evolved anywhere on the Red Planet.
The researchers think that microbes emerged on Mars around the same time that life was getting started on Earth.
However, after about one billion years, Mars’ climate began to change rapidly as solar winds stripped away its atmosphere – leaving the planet very cold and dry.
Professor Garrett says: ‘Those harsh conditions on Mars after 1 billion years would put strong limits on body size and complexity of any lifeform.
‘It took really complex life, like animals, another 3 billion years before they appeared on the Earth, where the conditions were much better to support energy-hungry complex life forms.’
If complex life had emerged, it would have needed to develop adaptations like thick skin or live underground to avoid the intense radiation of the Martian surface. Pictured: AI-generated impression
On Earth, some of the first animals to evolve were simple filter feeders. Filter feeders also survive in extreme environments such as hydrothermal vents, so complex Martian life might have followed a similar evolutionary trajectory. Pictured: AI-generated impression
In the unlikely case that more complex life did evolve, Mars’ harsh conditions would also put strong constraints on what it might look like.
‘It would need to be adapted to survive the intense UV radiation from the Sun, extreme cold, and limited liquid water – we don’t really see complicated animal life in such environments,’ says Professor Garret.
He adds: ‘If they were present, they would need protection from the UV radiation from the sun – maybe a thick skin, for example, or perhaps mostly living under the Martian soil.’
That means complex life might resemble creatures on Earth that live in exceptionally harsh environments, such as desert-dwelling lizards or the simple filter-feeders that survive near hydrothermal vents.
This article was originally published by a www.dailymail.co.uk . Read the Original article here. .