Life’s basic chemistry may not necessarily begin in warm ponds on young planets but rather in the icy dark regions between stars. A recent study has shown that cosmic dust grains can play a crucial role in stitching together amino acids into short peptides, even in environments lacking liquid water. This discovery raises the possibility that life-friendly chemistry may be more common throughout the universe than previously thought. The question now is whether these protein-like chains need to wait for planets with oceans to form or if they can start emerging much earlier, in the depths of space.
The findings indicate that space itself has the ability to assemble these chains long before planets even come into existence, providing young worlds with a chemical “starter kit” for life. Proteins, which are essential for various functions within living cells, are made up of smaller units called amino acids that are linked together to form peptides. Previous studies have focused on the presence of amino acids in meteorites and comets, but there has been a lack of clear evidence demonstrating the formation of peptides under realistic space-like conditions.
In the recent study, researchers concentrated on glycine, the simplest amino acid involved in protein synthesis. Thin layers of frozen glycine were placed on a cold surface in a vacuum chamber simulating the conditions of a dense cloud of gas and dust in space. The glycine layer was then bombarded with charged particles to mimic cosmic rays, which are high-energy radiation that permeates interstellar clouds. The results showed the formation of glycylglycine, a basic two-unit peptide, as well as other complex organic molecules and water, indicating that peptides can indeed form under cold, dry, space-like conditions.
Although the study has its limitations, such as the simplified dust grain surface and the focus on only one amino acid, it complements earlier research suggesting that space can facilitate the assembly of key components of life’s chemistry long before Earth-like environments are present. This shifts the narrative of life’s origins from traditional Earth-centric environments to the vast gas and dust clouds that eventually collapse to form stars and planets.
If peptides can routinely form on icy dust grains in these clouds, they can be incorporated into comets and asteroids, which may then deliver them to young planets during their formation. This implies that new planets could have a much richer inventory of pre-formed, protein-like molecules than previously assumed. The idea that basic chemistry of life may not be rare or fragile but rather a natural outcome of processes in star-forming regions across the universe increases the likelihood that rocky planets begin their existence already seeded with complex organic molecules.
Future space missions that collect samples from comets, asteroids, or interstellar dust could potentially validate this concept by identifying not just individual amino acids but also short peptides like those produced in the laboratory experiments. The discovery of such molecules would strengthen the argument that life on Earth, and possibly elsewhere, owes its existence in part to the chemistry that occurs in the cold, dark expanses of space.
