Ancient asteroid impacts 'created building blocks of life' on Earth

Ancient asteroid impacts ‘created the building blocks of life’ on Earth – and possibly Mars too – seabed crater simulations reveal

  • Researchers recreated the conditions found inside craters made by asteroids
  • They realised that amino acids could be created within these ancient craters 
  • These asteroids hit the Earth four billion years ago and may have brought life

Asteroids colliding with the Earth four billion years ago created the building blocks of life on our planet and possibly even on ancient Mars, a new study claims. 

Researchers from Tohoku University in Japan recreated the conditions present in seabed craters made by the space rocks crashing into the young Earth.

The team say these seabed craters hold the secret to how these ancient space rocks brought vital organic molecules to both worlds – billions of years ago.

When the asteroids crashed down to Earth they created amino acids – the basic components of proteins that are the building blocks of life, the lab study found.

The new findings add to evidence that life came from outer space, the authors claim, adding that it may have also led to the evolution of microscopic life on Mars. 

Researchers from Tohoku University in Japan recreated the conditions present in seabed craters made by the space rocks crashing into the young Earth

It’s known the Red Planet was once covered in water – and was bombarded with space rocks billions of years ago, say scientists. 

PANSPERMIA: HOW LIFE CAME TO EARTH FROM THE STARS 

Panspermia is a theory that suggests life spreads across the known physical universe, hitchhiking on comets or meteorites.

Extremophiles, capable of surviving the inhospitable conditions of space, could become trapped in debris that is ejected into space after collisions between asteroids and planets that harbour life.

These dormant life-forms may then travel for an extended amount of time before colliding randomly with other planets.

One argument that supports the panspermia theory is the emergence of life soon after the heavy bombardment period of earth, between 4 and 3.8 billion years ago. 

The earliest evidence for life on Earth suggests it was present some 3.83 billion years ago, overlapping with this bombardment phase.  

The evidence, based on lab experiments simulating asteroid crashes, explains how life got kick-started on Earth. The same phenomenon quite possibly happened on Mars – before it got stripped of its atmosphere.

The findings, published in the journal Scientific Reports, is based on lab experiments simulating the conditions resulting from asteroids crashing into the ocean.

Lead author Professor Yoshihiro Furukawa, of Tohoku University in Japan, said that finding amino acid formation from carbon dioxide and molecular nitrogen demonstrates life’s building blocks can be made from these ubiquitous compounds.

He said the idea a vast ocean existed on Mars also raises interesting avenues for exploration in terms of finding ancient signs of life on the Red Planet. 

At the time carbon dioxide and nitrogen are likely to have been the major constituent gases of the atmosphere when the Martian ocean existed.

As with the Earth, amino acid formation following an asteroid impact ‘provides a possible source of life’s ingredients on ancient Mars’, said Furukawa. 

‘The study discovered the emergence of amino acids that serve as the building blocks for proteins,’ he said. 

The question of there ever having been life on Mars is regarded as ‘the biggest of them all’ by people in the astrobiology community.

The Red Planet once had pools of water at the surface, these can be seen today etched into the rock and as huge canyons carved out by ancient now dried rivers.

Valles Marineris would stretch from Los Angeles to New York – and is the longest and deepest canyon in the solar system. 

The stunning features on today’s Mars prove it was once awash with water.

There are two explanations for the origins of life’s building blocks – both on Earth and on the Red Planet.

One is extraterrestrial delivery such as meteorites and internal, or ‘endogenous’, formation – known as panspermia.

‘The presence of amino acids and other biomolecules in meteorites points to the former,’ said Professor Furukawa.

Using a gas gun, his team mimicked a meteorite landing in an ocean – like in the one in the Gulf of Mexico 66 million years ago that wiped out the dinosaurs.

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 in their experiment as these gases were the two major components in the atmosphere of the early Earth.

Conditions on Mars would have been pretty similar to those on the ancient Earth more than four billion years ago – before it was stripped of its magnetic shield.

The evidence, based on lab experiments simulating asteroid crashes, explains how life got kick-started on Earth. The same phenomenon quite possibly happened on Mars – before it got stripped of its atmosphere

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.

What is still a mystery to scientists is how the building blocks of life 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 – that fell to Earth in Australia over 50 years ago – shows it contains 70 kinds of amino acids.

The Murchison meteorite contained grains of stardust formed seven billion years ago – before the Sun was formed. 

Furukawa added: ‘Further investigations will reveal more about the role meteorites played in bringing more complex biomolecules to Earth – and Mars.’  

Research has been published in the journal Scientific Reports. 

EARTH HAS HAD FIVE GREAT EXTINCTION EVENTS WITH THE MOST FAMOUS A DINOSAUR KILLING ASTEROID

Five times, a vast majority of the world’s life has been snuffed out in what have been called mass extinctions.

End-Ordovician mass extinction
The first of the traditional big five extinction events, around 540 million years ago, was probably the second most severe. Virtually all life was in the sea at the time and around 85% of these species vanished.

Late Devonian mass extinction

About 375-359 million years ago, major environmental changes caused a drawn-out extinction event that wiped out major fish groups and stopped new coral reefs forming for 100 million years.

Five times, a vast majority of the world’s life has been snuffed out in what have been called mass extinctions. The most famous may be the End-Cretaceous, which wiped out the dinosaurs. Artist’s impression

End-Permian mass extinction (the Great Dying)
The largest extinction event and the one that affected the Earth’s ecology most profoundly took place 252 million years ago. As much as 97% of species that leave a fossil record disappeared forever.

End-Triassic mass extinction
Dinosaurs first appeared in the Early Triassic, but large amphibians and mammal-like reptiles were the dominant land animals. The rapid mass extinction that occurred 201 million years ago changed that.

End-Cretaceous mass extinction

An asteroid slammed down on Earth 66 million years ago, and is often blamed for ending the reign of the dinosaurs.

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