David Coulter was in Copenhagen when he got an email that catapulted him into the stars. Coulter, 36, is a self-taught programmer. He spent 10 years in industry jobs, then left for graduate studies in astronomy and astrophysics at UC Santa Cruz, which operates Lick Observatory on Mount Hamilton. “I just wanted to learn about outer space,” he said. He picked the right place. The second-year grad student found himself on a team that was the first to take images of neutron stars merging, beating a group from Harvard, perhaps explaining the origin of metals such as gold and uranium....