Building blocks of life such as amino acids are able to form in dark interstellar clouds long before the areas of gas and dust turn into stars and planets, new study reveals.
An international team of scientists, led by experts from Queen Mary University of London, simulated the conditions found within dark interstellar clouds of dust.
They discovered that glycine, the simplest amino acid and an important building block of life, can form under the harsh conditions that govern chemistry in space.
This suggests that glycine, and possibly other amino acids, are able to form in dense interstellar clouds well before they transform into new stars and planets.
The amino acids are stored in comets – the most pristine material in our Solar System dating back to its earliest days – which then deliver them to young planets.
They discovered that glycine, the simplest amino acid and an important building block of life, can form under the harsh conditions that govern chemistry in space
‘The building blocks of the proteins relevant to life on Earth could potentially form at the very earliest stages of star formation as well and persist until planetary systems are established,’ lead author Dr Sergio Ioppolo told MailOnline.
Comets are the most pristine material in our Solar System and reflect the molecular composition present at the time our Sun and planets were just about to form.
The detection of glycine in the coma of comet 67P/Churyumov-Gerasimenko and in samples returned to Earth from the Stardust mission suggests that amino acids, such as glycine, form long before stars or planets.
However until recently, it was thought that glycine formation required energy, setting clear constraints to the environment in which it can be formed.
In the new study, a team of astrophysicists and astrochemical modellers, were able to show that it is possible for glycine to form on the surface of icy dust grains, in the absence of energy, through ‘dark chemistry’.
An international team of scientists, led by experts from Queen Mary University of London, simulated the conditions found within dark interstellar clouds of dust
‘The seeds of life are already formed well before stars and planets are born and as the process we have studied is universal, this also means that the Universe must be littered with molecules that we consider the building blocks of life as we know it.’
‘Now we need to go and find them,’ said Iopolo in an interview with MailOnline.
The findings contradict previous studies that have suggested UV radiation was required to produce this molecule.
The team, made up of researchers from around the world, was mostly based at the Laboratory for Astrophysics at Leiden Observatory, the Netherlands.
Dr Ioppolo, from Queen Mary University of London, said dark chemistry is chemistry without the need of energetic radiation and forms in dark clouds away from stars.
‘In the laboratory we were able to simulate the conditions in dark interstellar clouds where cold dust particles are covered by thin layers of ice,’ he said.
They are then ‘subsequently processed by impacting atoms causing precursor species to fragment and reactive intermediates to recombine.’
The scientists first showed methylamine, the precursor species of glycine that was detected in the coma of the comet 67P, could form.
Then, using a unique ultra-high vacuum setup, equipped with a series of atomic beam lines and accurate diagnostic tools, they were able to confirm glycine could also be formed, and that the presence of water ice was essential in this process.
Further investigation using astrochemical models confirmed the results and allowed the researchers to extrapolate data obtained on a typical laboratory timescale of just one day to interstellar conditions, bridging millions of years.
The detection of glycine in the coma of comet 67P/Churyumov-Gerasimenko (pictured) and in samples returned to Earth from the Stardust mission suggests that amino acids, such as glycine, form long before stars or planets
‘From this we find that low but substantial amounts of glycine can be formed in space with time,’ said Professor Herma Cuppen from Radboud University, Nijmegen.
‘The important conclusion from this is that molecules that are considered building blocks of life already form at a stage that is well before the start of star and planet formation,’ said Harold Linnartz, from Leiden Observatory.
‘Such an early formation of glycine in the evolution of star-forming regions implies that this amino acid can be formed more ubiquitously in space and is preserved in the bulk of ice before inclusion in comets and planetesimals that make up the material from which ultimately planets are made.’
Glycine, and possibly other amino acids, are able to form in dense interstellar clouds well before they transform into new stars and planets. They could then be delivered to planets like a young Earth on comets or asteroids
‘Once formed, glycine can also become a precursor to other complex organic molecules,’ concluded Dr Ioppolo.
‘Following the same mechanism, in principle, other functional groups can be added to the glycine backbone, resulting in the formation of other amino acids, such as alanine and serine in dark clouds in space.
‘In the end, this enriched organic molecular inventory is included in celestial bodies, like comets, and delivered to young planets, as happened to our Earth and many other planets.’