A millisecond flash crossed billions of light-years before anyone noticed it

In 2007, astronomers combing through old data found a radio pulse lasting five milliseconds yet carrying as much energy as the Sun releases in a month, traced back to a galaxy far beyond our own. These fast radio bursts stayed unexplained for over a decade, until one was finally caught coming from a magnetar inside the Milky Way itself in 2020.

— Duncan Lorimer et al., A Bright Millisecond Radio Burst of Extragalactic Origin — Science, 2007