Carbon sources spotted in cold interstellar clouds

To help understand the emergence of life on Earth, some scientists are trying to unravel the cosmic carbon cycle . The interstellar chemistry of polycyclic aromatic hydrocarbons (PAHs)—a large family of carbon-containing molecules found in space—is an enticing place to start. Although these many-ringed molecules are abundant in the interstellar medium, specific PAHs have been difficult to identify with infrared telescopes because of their broad, overlapping signal peaks. But recently, using nearly 1,500 hours of data collected with the Green Bank Telescope, a group of researchers has identified 1-cyanopyrene in the Taurus molecular cloud ( Science 2024, DOI: 10.1126/science .adq6391 ). The molecule is the largest PAH detected with a radio telescope. “We think that a lot of carbon is locked up in this particular PAH,” says chemist Ilsa Cooke of the University of British Columbia, one of the paper’s coauthors, due to its relative abundance. The four fused aromatic