Building blocks of life can form long before stars

Glycine forms in icy dust grains via dark chemistry, independent of UV radiation or energy.

Key Takeaways

1. Amino acids like glycine can form in dark interstellar clouds well before stars and planets emerge.
2. This discovery shifts the paradigm, showing that glycine formation doesn’t require energetic radiation, as previously believed.
3. Experiments revealed glycine forms on icy dust grains in cold, radiation-free environments through “dark chemistry.”
4. The study highlights that glycine may act as a precursor to other essential organic molecules, like alanine and serine.
5. These findings suggest that the building blocks of life could be widespread and preserved in cosmic ices.

________

Early Formation of Life’s Building Blocks

A groundbreaking study published in Nature Astronomy has revealed that amino acids, essential for life, can form in dark interstellar clouds long before stars and planets emerge. Glycine, the simplest amino acid, was shown to form on the surface of icy dust grains in cold, energy-deprived environments through a process called “dark chemistry.” These findings challenge the long-standing belief that UV radiation was required to create glycine, significantly expanding our understanding of how life’s precursors emerge in space.

Comets, which preserve the molecular composition of the early Solar System, provided initial clues. Glycine had been detected in comet 67P/Churyumov-Gerasimenko and in samples from NASA’s Stardust mission, suggesting amino acids form pre-stellar formation. However, this study, conducted by an international team led by Dr. Sergio Ioppolo of Queen Mary University of London, demonstrated that glycine could form without energy, solely through reactions on icy dust particles.

How Glycine Forms Without Energy

The team simulated interstellar cloud conditions in a lab at Leiden Observatory in the Netherlands. Dust particles coated with water ice were exposed to atoms, leading to reactions that fragmented precursor molecules and recombined them into glycine. Using advanced tools like an ultra-high vacuum setup with atomic beam lines, researchers first confirmed the formation of methylamine, a glycine precursor, and then glycine itself.

Astrochemical models further validated these experimental results, showing that glycine forms gradually over millions of years under interstellar conditions. Professor Herma Cuppen from Radboud University emphasized that these models allowed researchers to extrapolate lab data to cosmic timescales, revealing that substantial amounts of glycine could accumulate in space.

Implications for Life and Space Exploration

The findings have profound implications. Harold Linnartz, Director of the Laboratory for Astrophysics at Leiden Observatory, noted that glycine’s early formation suggests it is preserved in cosmic ice and later incorporated into comets and planetesimals, the building blocks of planets. This means glycine, and possibly other amino acids, could be delivered to young planets, providing a foundation for life as happened on Earth.

Dr. Ioppolo highlighted the potential for glycine to serve as a precursor to more complex organic molecules like alanine and serine, which could also form in dark interstellar clouds. These enriched molecules may eventually contribute to the organic inventory of celestial bodies, shaping the conditions for life on planets.

This discovery not only broadens our understanding of the origins of life’s building blocks but also raises the possibility that such molecules are ubiquitous in the universe, formed long before stars or planets come into being.