This post is part of a series about quick questions and answers about the Virgo experiment and the science of gravitational waves. Do you have a quick question? Tell us and we will reply!
Are there other instruments like Virgo?
Today there is an initial network of gravitational wave interferometers around the world. In fact, having more than one detector is a key factor in rejecting spurious signals due to local noises and to localize the source position in the sky. There are the two 4-km long interferometers, of the Laser Interferometer Gravitational Observatory (LIGO), built in the United States in Hanford, Washington State and in Livingston, Louisiana. LIGO has also undergone a major upgrade and the Advanced LIGO detectors have resumed their observations in September 2015. There is also the GEO600 interferometer built near Hannover that has 600-meter long arms. A fifth interferometer, KAGRA, is under construction inside a mountain in the Kamioka mine in Japan and will soon be completed operative. The LIGO collaboration is also planning to install a third 4-km interferometer in India, within the LIGO-India project.