Some 7.5 billion years ago, a supernova heralding the birth of a black hole went off halfway across the universe, sending a pencil-beam flash of light toward Earth that was briefly visible to the naked eye on March 19.

UC Berkeley's Joshua Bloom and colleagues, who analyzed data from PAIRITEL and Gemini South to characterize the gamma-ray burst, see such bursts as a way to probe the early universe.