Upgraded LIGO resumes detecting gravitational waves with enhanced sensitivity.

The Laser Interferometer Gravitational-Wave Observatory (LIGO) has resumed operations after three years of upgrades and maintenance, making it 30% more sensitive. The increased sensitivity means the detectors will pick up gravitational wave signals at a higher rate, detecting a merger every two or three days. The project kicked off a new run of observations, dubbed O4, this week, with Japan's KAGRA detector set to join in months and Europe's Virgo detector to become part of the data gathering later this year.