Overview: Observing events that occur in milliseconds, including the recently detected gravitational wave created by the collision of two neutron stars. Chris Lintott joins astronomers trying to detect a gamma ray burst in space, while Lucie Green discovers how similar phenomena can be found much closer to home. We're used to thinking that the universe operates on timescales of millions or even billions of years, where change happens with imperceptible slowness. But now we've discovered a whole catalogue of events that happen over much shorter times - seconds or even milliseconds. And these sudden, transient occurrences are among the most mysterious, powerful and destructive events in the universe. Observing them has raised exciting new questions about the way the universe works. This month The Sky at Night explores this world of transient phenomena. We hear more about the explosive event that created the recently detected gravitational wave - the collision of two neutron stars. And Chris spends 24 hours at the SWIFT space telescope base in Leicester in an attempt to detect a gamma ray burst - the most powerful and extreme short-term event known. Maggie goes to meet the team that are searching for the mysterious, barely understood transient phenomena called fast radio bursts. And Lucie Green reveals that some important short-term phenomena can occur much closer to home too. Astronomy used to be about staring up at the unchanging sky, so this search for transitory objects is truly revolutionary. It's time to enter the spectacular world of astronomy that takes place... in the blink of an eye...