A new experiment could finally help answer the question of how life began on Earth.
Researchers have recreated interstellar icy grains coated with carbon dioxide and water – and found that in the conditions of space, they can produce a key building block of life.
They say their research provides ‘compelling new evidence’ a key component for life was found to be generated in outer space and delivered to Earth in its first one billion years by meteorites or comets.
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The Comet 67P/Churyumov-Gerasimenko from a distance of 285 km: Researchers have recreated interstellar icy grains coated with carbon dioxide and water – and found that in the conditions of space, they can produce a key building block of life.
University of Hawaii at Manoa researchers, in collaboration with colleagues in France and Taiwan, used an ultra-high vacuum chamber cooled down to 5 K (-450°F) in the W.M. Keck Research Laboratory in Astrochemistry at UH Manoa to recreate the icy grains.
They found that when exposed to ionizing radiation in the form of high-energy electrons to simulate the cosmic rays in space, multiple phosphorus oxoacids like phosphoric acid and diphosphoric acid were synthesized.
‘On Earth, phosphine is lethal to living beings,’ said UH Manoa graduate student Andrew Turner, now assistant professor at the University of Pikeville, the paper’s lead author.
‘But in the interstellar medium, an exotic phosphine chemistry can promote rare chemical reaction pathways to initiate the formation of biorelevant molecules such as oxoacids of phosphorus, which eventually might spark the molecular evolution of life as we know it.’
The phosphorus compounds were then incorporated in biomolecules found in cells in living beings on Earth.
The breakthrough research is outlined in ‘An Interstellar Synthesis of Phosphorus Oxoacids,’ authored by UH Manoa graduate student Andrew Turner, now assistant professor at the University of Pikeville, and UH Manoa chemistry Professor Ralf Kaiser in the September issue of Nature Communications.
According to the study, phosphates and diphosphoric acid are two major elements that are essential for these building blocks in molecular biology.
They are the main constituents of chromosomes, the carriers of genetic information in which DNA is found.
Together with phospholipids in cell membranes and adenosine triphosphate, which function as energy carriers in cells, they form self-replicating material present in all living organisms.
The researchers argue that ‘life may have been seeded here on Earth by life-bearing comets as soon as conditions on Earth allowed it to flourish (about or just before 4.1 Billion years ago)’
Kaiser added, ‘The phosphorus oxoacids detected in our experiments by combination of sophisticated analytics involving lasers, coupled to mass spectrometers along with gas chromatographs, might have also been formed within the ices of comets such as 67P/Churyumov-Gerasimenko, which contains a phosphorus source believed to derive from phosphine.’
‘Upon delivery to Earth by meteorites or comets, these phosphorus oxoacids might have been available for Earth’s prebiotic phosphorus chemistry,’ the team say.
‘Hence an understanding of the facile synthesis of these oxoacids is essential to untangle the origin of water-soluble prebiotic phosphorus compounds and how they might have been incorporated into organisms not only on Earth, but potentially in our universe as well. ‘
WHAT WAS THE ‘CAMBRIAN EXPLOSION’?
Scientists have long speculated that a large oxygen spike during the ‘Cambrian Explosion’ was key to the development of many animal species.
The Cambrian Explosion, around 541 million years ago, was a period when a wide variety of animals burst onto the evolutionary scene.
Before about 580 million years ago, most organisms were simple, composed of individual cells occasionally organised into colonies.
Over the following 70 or 80 million years, the rate of evolution accelerated and the diversity of life began to resemble that of today.
It ended with the Cambrian-Ordovician extinction event, approximately 488 million years ago.
A recent study linked the historic rise in oxygen responsible for the formation of animal life on Earth to fossil fuels. Pictured: This black shale, formed 450 million years ago, contains fossils of trilobites and organic material that helped support these in oxygen