The Laser Interferometer Gravitational-wave Observatory is back on the hunt for ripples in spacetime, months after reporting the first signature of a black hole collision in gravitational waves.
After a series of upgrades, the LIGO detectors at Hanford in Washington state and near Livingston, La., made the transition from engineering test runs to science observations at 8 a.m. PT today.
LIGO’s first detection of gravitational waves – a phenomenon that was predicted by Albert Einstein’s theory of general relativity back in 1915 – occurred during an engineering run in September 2015. But it took until February for the LIGO team to confirm the detection and report it to the world.
Scientists determined that the faint perturbations in the fabric of spacetime were created by a smash-up involving two black holes 1.3 billion light-years away. The violent collision created one bigger black hole, but in the process, an amount of mass equivalent to three suns was converted into gravitational waves.
LIGO picked up a second, smaller pulse of gravitational waves last December. Then the detectors were shut down in January for the upgrades.
