Spacetime is not an emptiness but an elastic membrane. When neutron stars (super-dense spheres the size of a city) or black holes collide, the membrane shudders: gravitational waves ripple across it. This effect was predicted by Einstein, and the cosmic trembling was heard thanks to detectors built with the participation of Rainer Weiss. Each such 'chirp' lasts a fraction of a second, and the light from it fades in minutes.
That's when the GstLAL program steps in — a virtuoso listener that spots a real signal amid noise in just 16 seconds. It runs almost non-stop (98% of the time) and in the latest observing season was first to warn about 222 out of 250 cosmic catastrophes. Moreover, 75 of those were detected by no one else: these signals nearly slipped away from science.
Interestingly, the space displacement from a wave is a thousand times smaller than a proton, yet LIGO's laser 'rulers' seize it nonetheless. GstLAL's success lies in its ability to act tens of seconds faster than its rivals, giving telescopes a chance to swivel toward the fading flash. The program's output matched the final catalog 93% of the time.
The GstLAL alarm sounds faster than a kettle boils: the average time is 16 seconds. This gives astronomers a chance to catch light that fades in minutes.