An international team of scientists have shown that glycine, the simplest amino acid and an important building block of life, can form under the harsh conditions that govern chemistry in space

Key takeaways

  • Glycine Formation in Space: Scientists have shown that glycine, a key building block of life, can form in the harsh conditions of space.
  • Dense Interstellar Clouds: Glycine and likely other amino acids form in dense interstellar clouds, long before new stars and planets form.
  • Dark Chemistry: Glycine can form through “dark chemistry” on icy dust grains without the need for energetic radiation, contrary to previous beliefs.
  • Comet Discoveries: Glycine has been found in comet 67P and samples from the Stardust mission, indicating amino acids form before stars.
  • Implications for Life: Early formation of glycine suggests that essential building blocks of life are preserved in ice and delivered to planets by comets.

The results, published in Nature Astronomy, suggest that glycine, and very likely other amino acids, form in dense interstellar clouds well before they transform into new stars and planets.

Comets are the most pristine material in our Solar System, reflecting the chemical makeup of our Sun and planets when they were forming. The discovery of glycine in the coma of comet 67P/Churyumov-Gerasimenko and in samples returned to Earth by the Stardust mission implies that amino acids like glycine occur long before stars. Until recently, it was considered that glycine creation needed energy, which limited the environments in which it could be created.

A global group of astrophysicists and astrochemical modelers, primarily employed at the Laboratory for Astrophysics at Leiden Observatory in the Netherlands, have demonstrated in a recent study that glycine can form on the surface of icy dust grains through “dark chemistry” in the absence of energy. The results defy earlier research that claimed UV light was necessary for the production of this chemical.

Lead author of the paper Dr. Sergio Ioppolo of Queen Mary University of London stated: “Dark chemistry is chemistry that doesn’t require energetic radiation.” We were able to recreate in the lab the circumstances seen in dark interstellar clouds, which are made up of cold dust particles coated in thin coatings of ice. These particles are then affected by atom impacts, which split precursor species and recombine reactive intermediates.

Precursors to other complex molecules

The scientists first demonstrated that methylamine, a precursor species of glycine found in the coma of comet 67P, might develop. Then, using a novel ultra-high vacuum apparatus outfitted with a number of atomic beam lines and precise diagnostic equipment, they were able to establish that glycine could also be synthesized, and that the presence of water ice was required in this process.

The results of the experiment were validated by additional study employing Astrochemical models, which also enabled the researchers to extend data collected on a typical laboratory timeframe of about one day to interstellar circumstances, spanning millions of years. The author of some of the modeling simulations in the article, Professor Herma Cuppen of Radboud University in Nijmegen, said, “From this we find that low but substantial amounts of glycine can be formed in space with time.”

Harold Linnartz, the director of the Laboratory for Astrophysics at Leiden Observatory, stated, “The important conclusion from this work 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.” “This suggests that glycine can form more widely in space and is preserved in the bulk of ice before inclusion in comets and planetesimals that make up the material from which planets are ultimately made,” according to the early creation of glycine in the evolution of star-forming areas.

Dr. Ioppolo observed, “Once formed, glycine can also become a precursor to other complex organic molecules.” additional functional groups can theoretically be attached to the glycine backbone by the same method, leading to the production of additional amino acids in black clouds in space, such alanine and serine. Ultimately, as has happened to our Earth and many other planets, this increased organic chemical inventory is given to newborn planets by celestial bodies like comets.

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