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

For the first time, scientists have identified multiple complex building blocks of life in the icy surroundings of a star located outside the Milky Way. Utilizing the James Webb Space Telescope (JWST), researchers detected five large carbon-based compounds around a protostar in the Large Magellanic Cloud, a 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, could deepen our understanding of how complex molecules formed in the early universe.

The Large Magellanic Cloud, part of a group of gravitationally bound galaxies that includes the Milky Way, is characterized by its hot, luminous stars that emit high levels of ultraviolet radiation. It also contains fewer heavy elements than the Milky Way, making its conditions similar to those expected in galaxies from the early universe. Marta Sewilo, an astronomer at the University of Maryland and NASA’s Goddard Space Flight Center, emphasized the significance of these conditions: “The harsh environments tell us more about how complex organic chemistry can occur in these primitive settings where fewer heavy elements like carbon, nitrogen, and oxygen are available for chemical reactions.”

In March 2024, researchers directed the JWST toward a developing star named ST6 in the Large Magellanic Cloud. Through sophisticated instruments measuring infrared light, they discovered five complex carbon-based molecules in the ice surrounding the star: methanol, acetaldehyde, ethanol, methyl formate, and acetic acid. Notably, while methanol had been previously detected in protostars outside the Milky Way, acetic acid—commonly found in vinegar—had never been conclusively identified in space ice until now.

“Before Webb, methanol had been the only complex organic molecule conclusively detected in ice around protostars, even in our own galaxy,” Sewilo remarked. She further noted that the exceptional quality of their observations allowed the team to gather extensive information from a single spectrum, yielding insights greater than ever before.

The researchers also detected potential signals indicating the presence of a chemical called glycolaldehyde. This molecule can react with others to form ribose, a crucial component of ribonucleic acid (RNA), which is essential for life as we know it.

The discovery of these complex molecules suggests that chemical reactions on the surfaces of dust grains can lead to the formation of intricate compounds, even in challenging environments. The team plans to conduct further studies to search for these and similar molecules around other protostars, both within the Milky Way and in nearby galaxies.

“With this discovery, we have made significant advancements in understanding how complex chemistry emerges in the universe, opening new possibilities for research into how life came to be,” Sewilo stated. As our exploration of the cosmos continues, findings like these pave the way for a deeper comprehension of the origins of life, potentially extending our search for extraterrestrial existence.