He found a Milky Way black hole 50 years ago, and finally got to see it

Bruce Balick penned an urgent letter to his research partner on the other side of the country. He feared other radio astronomers were close on their heels, including one by the name of Fred Lo.

"We'd better publish fast if we want to beat him into print," Balick wrote to Robert L. Brown, his collaborator, in the spring of...