Frozen molecules hiding in the shadows of another galaxy have revealed new secrets about cosmic chemistry. Using the James Webb Space Telescope (JWST), astronomers detected complex organic molecules—considered the raw ingredients of life—around a forming star outside our Milky Way. The discovery took place in the Large Magellanic Cloud (LMC), a nearby dwarf galaxy, and opens an entirely new chapter in the search for life’s chemical origins.
JWST’s Breakthrough In The Tarantula Nebula’s Backyard
The findings, published in Astrophysical Journal Letters, detail how Marta Sewiło of the University of Maryland and her team used JWST’s Mid-Infrared Instrument (MIRI) to detect complex organic molecules (COMs) frozen within dust grains surrounding a massive protostar named ST6. This object lies within the star-forming region N158, close to the iconic Tarantula Nebula, about 163,000 light-years away. Such COMs—carbon-bearing molecules with more than six atoms—serve as precursors to amino acids and sugars, which are key components of life as we know it.
What makes this discovery groundbreaking is not just the location but the form of the molecules themselves. These compounds were detected in their icy phase, before being warmed and released as gases during later stages of star formation.
“JWST has enabled the detection of COM ices, but to date there are only four protostars in the Milky Way where we have detected icy COMs, and only one in the LMC — ST6,” said Sewiło.
This milestone underscores JWST’s ability to peer deeper into cosmic nurseries than any telescope before it.
Clues To Life’s Earliest Chemistry
The Large Magellanic Cloud is an astrophysical time capsule. Its lower concentration of heavy elements and intense ultraviolet radiation mimic the conditions of galaxies that existed billions of years ago. By studying ST6, scientists gain insight into how complex chemistry might have unfolded in the early universe. The relatively low abundance of COMs compared with similar regions in the Milky Way hints at how environmental differences influence organic molecule formation.
Among the signatures detected by JWST are several unidentified absorption features—possible markers of even more intriguing chemistry.
“We have found evidence that several of the unidentified absorption features could be attributed to glycolaldehyde, but the detection remains inconclusive since more laboratory spectra are needed to verify it,” said Sewiło, referring to glycolaldehyde’s role as a precursor to ribose, a building block of RNA.
If confirmed, this would strengthen the case that the universe began assembling the ingredients for biology far earlier and more widely than once imagined.
Complex organic molecules have been identified in the icy mantle on dust grains around the protostar ST6 in the Large Magellanic Cloud. (Image credit: NASA’s Goddard Space Flight Center)
A Glimpse Into The Chemistry Of Creation
Detecting COMs in frozen form provides a snapshot of molecular evolution before stars fully ignite. As ST6 continues to heat up, its surrounding ice will sublimate, releasing these molecules into space where further reactions could create even more complex compounds. Some of these, such as amino acids, have already been discovered in comets within our solar system—relics of a similar process that occurred 4.5 billion years ago.
“It is likely that more COMs are present in the ices around ST6, and our results highlight the need for more laboratory experiments,” added Sewiło. Laboratory data are essential to match observed infrared spectra with specific molecules, confirming their identity and abundance.
This interplay between observation and experimentation lies at the heart of astrochemistry—an emerging field bridging space science and the origins of life.
By mapping the frozen chemistry of the Large Magellanic Cloud, astronomers are not only uncovering the secrets of one distant star’s nursery—they are retracing the first steps of life’s chemical journey across the cosmos.