Ancient asteroid impacts created the building blocks of life on Earth and Mars, according to new research.
Seabed craters hold the secret to how meteorites brought vital organic molecules to both worlds billions of years ago.
It’s known the Red Planet was once covered in water and was bombarded with space rocks billions of years ago, say scientists.
Now a study has shown when space rocks splash down they make amino acids, the basic components of proteins.
It could explain how life got kick-started on Earth and the same phenomenon may have happened on Mars before it was stripped of its atmosphere.
The findings, published in the journal Scientific Reports, is based on lab experiments and simulations of asteroids crashing into the ocean.
It adds to claims life came from outer space and will encourage those who believe it’s widespread in the universe.
Lead author Professor Yoshihiro Furukawa, of Tohoku University in Japan, said: “The finding of amino acid formation from carbon dioxide and molecular nitrogen demonstrates the importance in making life’s building blocks from these ubiquitous compounds.”
He said the idea a vast ocean existed on Mars also raises interesting avenues for exploration.
At the time carbon dioxide and nitrogen are likely to have been the major constituent gases of the atmosphere when the ocean existed.
An impact-induced amino acid formation also provides a possible source of life’s ingredients on ancient Mars, said Prof Furukawa.
He said: “The study discovered the emergence of amino acids that serve as the building blocks for proteins.
“It shows the role of meteorites in bringing life’s molecules to Earth – and potentially Mars.”
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The question of there ever having been life on Mars is regarded as “the biggest of them all.”
It once had pools at the surface. Etched into the rock are huge canyons carved out by rivers.
Valles Marineris would stretch from Los Angeles to New York – and is the longest and deepest in the solar system. The stunning features prove it was awash with water.
There are two explanations for the origins of life’s building blocks – extraterrestrial delivery such as meteorites and internal, or ‘endogenous’, formation.
Prof Furukawa said: “The presence of amino acids and other biomolecules in meteorites points to the former.”
Using a gas gun, his team mimicked a meteorite landing in an ocean – like in the Gulf of Mexico 66 million years ago when the dinosaurs were wiped out.
The tests revealed the formation of amino acids such as glycine and alanine that build and maintain living organisms.
They are direct constituents of the proteins that trigger many biological processes which otherwise would not take place.
The researchers used carbon dioxide and nitrogen as these gases were the two major components in the atmosphere of the early Earth.
Conditions on Mars would have been pretty similar more than four billion years ago – before it was stripped of its magnetic shield.
Prof Furukawa said: “Making organic molecules form reduced compounds like methane and ammonia are not difficult.
“But they are regarded as minor components in the atmosphere at that time.”
Several lines of evidence suggest some of the building blocks of life were delivered to the primitive Earth via meteoroids.
But scientists would still like to know how they got into the meteoroids in the first place.
One suggestion is complex chemical reactions involving water took place.
An analysis of the famous Murchison meteorite shows it contains 70 kinds of amino acids.
It fell to Earth in Australia over 50 years ago and contains grains of stardust formed seven billion years ago – predating the Sun.
Prof Furukawa added: “Further investigations will reveal more about the role meteorites played in bringing more complex biomolecules to Earth – and Mars.”
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