Cosmic dust chemistry forges peptide building blocks in deep space

by Robert Schreiber
Berlin, Germany (SPX) Mar 03, 2026
New experiments show that key molecular building blocks for life can form spontaneously on icy dust grains in deep space long before planets emerge from collapsing gas clouds.

In a laboratory at Aarhus University and at the HUN-REN Atomki facility in Hungary, researchers Sergio Ioppolo and Alfred Thomas Hopkinson reproduced the extreme conditions in giant interstellar dust clouds, where temperatures fall to about minus 260 degrees Celsius and pressures are near perfect vacuum. Inside a small chamber, they deposited molecules onto a surface, maintained ultra high vacuum by constantly pumping away stray gas, and then irradiated the sample with beams that mimic cosmic rays.

Earlier work had already established that simple amino acids such as glycine can form in interstellar space, but the team wanted to know whether more complex species arise directly on dust grains before they participate in the birth of stars and planets. Peptides, which are short chains of amino acids, are of particular interest because they can join together to form proteins that are essential for life as it is known on Earth.

The researchers placed glycine in the chamber and bombarded it with cosmic ray analogs generated by an ion accelerator at HUN-REN Atomki, then analyzed the products. They observed that glycine molecules reacted with each other to form peptides and water, indicating that an energetic, non aqueous pathway to peptide formation operates under realistic interstellar conditions on dust grain surfaces.

According to the team, this mechanism implies that some of the precursors to proteins can arise directly within the cold, tenuous clouds where new stars and planetary systems are born. The result challenges the long held assumption that only very simple molecules form in these regions and that more complex chemistry must wait until material has collapsed into warmer, denser protoplanetary disks.

The study suggests that complex organic molecules are likely far more widespread in the universe than previously believed. As giant clouds of gas and dust eventually collapse into stars and rocky planets, tiny molecular building blocks created on dust grains can be delivered to planetary surfaces.

If those planets orbit within a habitable zone where conditions allow liquid water, the presence of pre formed peptides and related compounds raises the probability that life might emerge. The researchers emphasize that the experiments do not reveal exactly how life begins, but they do show that multiple complex molecules required for early prebiotic chemistry arise naturally in space.

The chemistry that links amino acids into peptides is a universal reaction, so demonstrating that glycine forms peptides under interstellar conditions implies that other amino acids can likely do the same. Hopkinson notes that all types of amino acids bond into peptides through the same mechanism, making it very probable that a rich variety of peptides exists on interstellar dust grains.

Amino acids and peptides are only part of the inventory needed for life, which also depends on components such as membranes, nucleobases, and nucleotides. Whether these other crucial molecular families also form efficiently in space remains an open question that the team at the Center for Interstellar Catalysis in Aarhus, funded by the Danish National Research Foundation, is now investigating.

Co author Liv Hornekaer, who leads the InterCat center, explains that these molecules are key building blocks for life and may actively participate in early prebiotic chemistry by catalyzing additional reactions. The group aims to map out how far space based chemistry can progress toward biological complexity before material ever reaches a young planet.

The authors conclude that many of the building blocks of life are already synthesized in interstellar environments, and they expect further work to uncover additional complex species. As observational and laboratory astrochemistry advance, the picture of a chemically rich universe in which life's ingredients are assembled long before planets form is becoming increasingly robust.

Research Report:An interstellar energetic and non-aqueous pathway to peptide formation