Scientists Discover Life’s Building Blocks in Ice Outside Milky Way

For the first time, scientists have detected multiple complex building blocks of life in the ice surrounding a star outside the Milky Way. Utilizing the James Webb Space Telescope (JWST), researchers identified five significant carbon-based compounds around a protostar known as ST6 in the Large Magellanic Cloud (LMC), a nearby dwarf galaxy approximately 160,000 light-years from Earth. This groundbreaking discovery, detailed in a study published on October 20 in the Astrophysical Journal Letters, offers new insights into the formation of complex molecules in the early universe.

The LMC, which orbits closely to the Milky Way, is characterized by its hot, luminous stars that emit copious amounts of ultraviolet radiation. Unlike the Milky Way, it contains fewer elements heavier than helium, creating conditions that resemble those expected in galaxies from the universe’s infancy. According to Marta Sewilo, an astronomer at the University of Maryland and NASA’s Goddard Space Flight Center, “What we learn in the Large Magellanic Cloud, we can apply to understanding these more distant galaxies from when the universe was much younger.”

During their observations in March 2024, the researchers focused on the developing star ST6 and discovered five complex carbon-based molecules in the icy environment surrounding the star: methanol, acetaldehyde, ethanol, methyl formate, and acetic acid. Notably, only methanol had previously been detected in protostars outside the Milky Way, while acetic acid, a primary component of vinegar, had never been conclusively identified in space ice before this study.

Sewilo noted, “Before Webb, methanol had been the only complex organic molecule conclusively detected in ice around protostars, even in our own galaxy. The exceptional quality of our new observations helped us gather an immense amount of information from a single spectrum, more than we’ve ever had before.”

The researchers also detected potential signals indicative of glycolaldehyde, a molecule that can react with others to form ribose, a crucial component of ribonucleic acid (RNA), which is essential for life. This discovery is significant, as it suggests that complex molecules can form through chemical reactions on dust grain surfaces, even under harsh conditions.

The implications of finding such complex molecules in the LMC are profound. It indicates that the building blocks of life may be more widespread in the universe than previously thought. The research team plans to conduct further studies to search for these and similar molecules around other protostars in both the Milky Way and nearby galaxies.

With this groundbreaking discovery, Sewilo remarked, “We’ve made significant advancements in understanding how complex chemistry emerges in the universe and opened new possibilities for research into how life came to be.” The findings not only advance our understanding of organic chemistry in primitive environments but also pave the way for future explorations into the origins of life beyond our planet.