“How did life originate?” Philosophers, scientists, and researchers have pondered this query since time immemorial. In the contemporary age, the prevailing assumption is that the fundamental components of life as we know it—amino acids, DNA, and RNA—coalesced spontaneously billions of years ago to form the first proteins. Nevertheless, every attempt to replicate this chemical process (“abiogenesis”) in a laboratory setting has yielded no success. Despite this, it is widely accepted that this seminal event occurred on Earth, most likely within its primordial oceans.
A recent investigation by an international consortium led by Aarhus University has questioned this long-held premise, demonstrating that proteins can readily assemble in the vacuum of outer space. At the Institute for Nuclear Research, part of the Hungarian Academy of Sciences (HUN-REN Atomki), the team simulated conditions characteristic of vast cosmic dust clouds. The findings, detailed in the journal Nature Astronomy, suggest that the constituents necessary for life may saturate the cosmos, substantially raising the statistical odds that humanity will eventually detect extraterrestrial existence.
Within a compact chamber, the group recreated the space environment by reducing the pressure to near zero and chilling the temperature to -260 °C. They also continuously evacuated gas particles from the enclosure, maintaining an ultra-high vacuum. Subsequently, the team introduced glycine into the chamber and subjected it to radiation mimicking cosmic rays, generated by the institute’s ion accelerator at HUN-REN Atomki, to gauge the resulting reactions. Specifically, the researchers aimed to ascertain if intricate molecules, such as peptides—short chains of amino acids linking together to build proteins—were forming.
“We observed glycine molecules begin to interact with each other, leading to the creation of peptides and water,” stated Alfred Thomas Hopkinson, the study’s lead author from the Interstellar Catalysis Center (CIC) at Aarhus University. “This implies that the identical procedure unfolds throughout interstellar space. It represents a stride toward building proteins on dust grains, the very materials from which rocky planets eventually materialize.”
Given that peptides are precursors to all components of known life, investigating their genesis location and mechanism is crucial for tracing life’s beginnings. This research not only substantiates earlier work confirming the presence of complex organic molecules (COMs) in space but also establishes that the chemical pathway for amino acid bonding is universal. This hints that the same reaction likely occurs with other, more complex amino acids essential for biology.
“We were keen to determine if more complex structures, like peptides, form organically upon the surfaces of dust particles before they participate in the formation of stars and planets. Previously, the expectation was that only very simple molecules could emerge in these clouds. It was assumed that more complex molecules arose much later, once gases began to condense into the disk that eventually evolves into a star. Our evidence clearly refutes this,” commented Sergio Ioppolo, a co-author from Aarhus University.
Within the standard paradigm of star formation, stars coalesce via the gravitational collapse of dense interstellar clouds of gas and dust. Remaining material settles into a disk orbiting the nascent star, eventually accreting to form planetary systems. Consequently, these findings suggest that life’s building blocks were already present within this process, effectively “seeding” new planets and providing the necessary prebiotic chemistry. For any planets situated within their star’s habitable zone, subsequent chemical evolution could lead to the emergence of life.
This discovery is significant because it implies that molecules necessary for life are far more prevalent than previously estimated and originate substantially earlier than presumed. This dramatically enhances the probability of life existing in other stellar systems, holding profound implications for astrobiology and the Search for Extraterrestrial Intelligence (SETI). Regrettably, as Hopkinson noted, this does not resolve the core mystery of how life first arose. In essence, the enigma of how and under what conditions these essential elements combined to spark life as we recognize it remains unsolved.
Nevertheless, their results provide critical insight into the initial stages of that process billions of years ago. “All types of amino acids link into peptides through the same reaction pathway. Therefore, it is highly probable that other peptides are also naturally synthesizing in interstellar space. While we haven’t explored this yet, we likely will in the future,” Hopkinson remarked. “A great deal remains to be uncovered, but our research group is dedicated to addressing as many of these fundamental questions as possible,” Ioppolo added. “We have already confirmed the origin of many life’s building blocks out there, and anticipate finding more in the coming times.”
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