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The building blocks of life, such as amino acids, are able to form in dark interstellar clouds long before areas of gas and dust turn into stars and planets, a new study reveals.
An international team of scientists, led by experts from Queen Mary University of London, simulated the conditions found inside dark interstellar dust clouds.
They found 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.
Amino acids are stored in comets – the most pristine material in our Solar System that dates back to its earliest days – which then deliver them to the young planets.
They found 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 proteins relevant to life on Earth could potentially form even in the very early stages of star formation and persist until planetary systems are established,’ lead author Dr. Sergio Ioppolo.
Comets are the most pristine material in our solar system and reflect the molecular composition present at the time our sun and planets were about to form.
The detection of glycine in the coma of comet 67P / Churyumov-Gerasimenko and in samples returned to Earth by the Stardust mission suggests that amino acids, such as glycine, are formed long before stars or planets.
However, until recently, the formation of glycine was thought to require energy, placing clear constraints on the environment in which it can form.
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 frozen 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 inside dark interstellar dust clouds
“The seeds of life have already formed long before the birth of stars and planets and since 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 have to go and see them,” Iopolo said in an interview with MailOnline.
The results contradict previous studies that have suggested that UV radiation was needed to produce this molecule.
The team, made up of researchers from around the world, was mostly based at the astrophysics laboratory of the Leiden Observatory in the Netherlands.
Dr Ioppolo, of Queen Mary University of London, said that dark chemistry is chemistry without the need for energy radiation and forms in dark clouds far from the stars.
“In the lab, we were able to simulate the conditions in dark interstellar clouds where cold dust particles are covered in thin layers of ice,” he said.
They are then “subsequently processed by striking the atoms, causing the fragmentation of the precursor species and the recombination of reactive intermediates”.
Scientists first showed that methylamine, the precursor species for glycine that was detected in the coma of comet 67P, could form.
Then, using a unique ultra-high vacuum configuration, equipped with a series of atomic beam lines and accurate diagnostic tools, they were able to confirm that glycine could also form and that the presence of water ice was essential in this process.
Further investigations using astrochemical models confirmed the results and allowed the researchers to extrapolate the data obtained on a typical laboratory time scale of just one day under interstellar conditions, spanning millions of years.
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 found that low but substantial amounts of glycine can form in space over time,’ said Professor Herma Cuppen of Radboud University, Nijmegen.
“The important conclusion that comes from this is that molecules considered to be building blocks of life are already formed at a stage that is well before the formation of stars and planets begins,” said Harold Linnartz, of the 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 conserved in most ice before inclusion in the comets and planetesimals that make up the material from which eventually the 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 such as 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.
“Eventually, this enriched organic molecular inventory is included in celestial bodies, such as comets, and delivered to young planets, as has happened to our Earth and many other planets.”
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