At least one prebiotic molecule, a component for the creation of life, can form in the harsh environment of interstellar space, away from stars and planets, new research suggests.
The amino acid glycine – the simplest amino acid, without which life cannot exist – was thought to require radiation from stars. But new laboratory experiments show that this is known as “dark chemistry”, which occurs without energetic radiation.
Glycine has been detected at some interesting places. It seems to have turned into meteorites, and into Venus’s atmosphere.
Of particular interest is its presence in the atmosphere of comet 67P / Churyumov-Gerasimenko, indicating that the molecule may have formed independently of the Sun or planets.
But laboratory experiments and modeling suggested that glycine is formed when interstellar ice is bathed in radiation – ultraviolet, cosmic, thermal, X-ray in the later stages of star formation.
At high enough energies, radiation can destroy amino acids, so a team of astronomers led by astronomer Sergio Igoppolo of Queen Mary University London in the UK looked at what alternative formation routes were.
And they found one.
“In the lab,” Ipolo said, “we were able to simulate conditions in dark interstellar clouds, where cold dust particles are covered with thin layers of ice and subsequently processed by impacting atoms, which are the precursors. To reactivate species and reactive intermediates affect recombination. “
Research began with methylamine, an amine precursor of glycine.
Although we have no evidence of the presence of glycine in the interstellar medium, astronomers have found methylamine – and methylamine was also detected on comet 67P / CG. In an independent set of experiments, researchers showed that methylamine can form non-energetically in interstellar conditions.
Subsequently, the researchers used a methylamine-enriched ice to determine if glycine could be formed under similar conditions.
They deposited it in a gas form in a high-high vacuum system called SURFRESIDE2Specially designed to investigate surface reactions in interstellar space. The system was cooled to an interstellar temperature of 13 Kelvin (-260 ° C, or -436 ° F) to make ice.
Researchers found that the chemical reactions in ice actually resulted in the formation of glycine. And this was necessary for the ice process.
Subsequently, he used astrochemical modeling to validate his findings. He extrapolated his experimental results, achieving in a time frame of only one day, millions of years beyond which cosmic processes can extend. And they found that glycine should be able to give sufficient time, in small but significant amounts, to the interstellar space.
It is unlikely that these molecules can develop much toward life in a cold free space vacuum.
What research means is that glycine and methylamine can form in space before they form a star (and, later, planetary formation) stops. Which, in turn, means that there is potentially a lot of prebiotic molecular matter, trapped in ice, and then freezing on meteorites, comets, planets, and eventually planets.
“Once formed, glycine can also become a precursor to other complex organic molecules,” said Ipolo.
“Following the same mechanism, in theory, 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. Finally, this organic molecular Enriches the list. The celestial bodies include objects such as comets, and reach young planets, as happened with our Earth and many other planets. “
The research has been published in Nature astronomy.