 Should nothing be done to remove or mitigate them, the expected physical signals would be buried in noise and would then remain undetectable.The design of detectors like Virgo and LIGO thus requires a detailed inventory of all noise sources which could impact the measurement, allowing a strong and continuing effort to reduce them as much as possible.During the data taking periods, dedicated software monitors in real time the noise levels in the interferometer, and deep studies are carried out to identify the loudest noises and mitigate them.