Science: Astronomers have discovered one of the largest carbon-based molecules ever found in deep space, located within the Torus molecular cloud, 430 light-years from Earth. The discovery is significant because it provides further clues that could help solve a long-standing puzzle in astrochemistry: where does carbon, the building block of life, come from? The molecule, called pyrene, is made up of four fused flat rings of carbon. It is therefore classified as a polycyclic aromatic hydrocarbon (PAH) – one of the most abundant complex molecules in the visible universe. PAHs were first detected in the 1960s in meteorites known as carbonaceous chondrites, remnants of the primordial nebula that formed our solar system.
“One of the biggest questions in the formation of stars and planets is how much of the chemical inventory from that early molecular cloud is inherited and goes on to form the base components of the solar system?” Brett McGuire, assistant professor of chemistry at the Massachusetts Institute of Technology, said in a statement that PAHs are believed to make up about 20% of the carbon found in space and are present at various stages of stars’ lives, from their formation to their death. Their stability and resilience to ultraviolet (UV) radiation makes them likely to survive even the harsh conditions of deep space. Researchers say they began searching for pyrene and other PAHs in the Torus Cloud when pyrene was found at high levels in samples collected from the near-Earth asteroid Ryugu. Finding these molecules in the birthplace of our solar system gives astronomers a direct link they have long been looking for. “What we’re looking at is the beginning and the end, and they’re showing the same thing,” McGuire said. “This is very strong evidence that this material from the early molecular cloud found its way into the ice, dust and rocky bodies that formed our solar system.”
