COLUMBUS, Ohio –
As the data heaped up, a knock suddenly came
When something gently knocked and knocked on LIGO's door
The source of a mysterious error in the data from a gravitational wave detector was unmasked: rap-tapp-tapping ravens with a thirst for shaved ice. At the Advanced Laser Interferometer Gravitational Wave Observatory, or LIGO, in the desert of Hanford, Washington, scientists noticed a signal that did not look like gravitational waves, physicist Beverly Berger said on April 16 at a meeting of the American Physical Society
Microphone sensor monitoring the LIGO environment caught the sound of pecking birds on tape in July 201
A raven, presumably freed from the heat of the desert, was caught red-handed. Changing the structure to prevent ice formation now prevents the ravens from knocking more and more.