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Il giorno 20/9/2017 dalle ore 12:00 alle ore 14:00 nella aula 14 - 15 IV piano St. 9 il prof. Hiroaki Yamamoto (LIGO Laboratory Caltech MC100-36, Pasadena (USA)) terrà il seminario dal titolo :
Einstein`s melody from billion years ago
Abstract : One century ago, Einstein formulated a theory of general relativity to address several problems in the Newton`s law of universal gravitation. Einstein`s general relativity predicted gravitational waves, which are radiated by the motion of very massive objects. It is very difficult to detect gravitational waves, and it took 100 years that the gravitational wave signals are directly observed. LIGO, Laser Interferometer Gravitational-wave Detector, project of the United State built two L-shaped laser interferometers with 4km arm length located at Hanford Washington and at Livingston Louisiana, 3000km apart. These two detectors caught a gravitational wave on September 14, 2015, followed by another two additional signals in December 2015 and January 2017. These gravitational waves were radiated billion years ago at the merger of two black holes. This detection opened a new era of astronomy just as the GalileoÃ¢?Ts telescope opened the new era of astronomy using visible light 400 years ago. Gravitational wave signals can be used to study the evolution of the universe and other interesting phenomena which cannot be observed using only electromagnetic signals. Recently, Virgo detector located at Cascina, Italy has joined the international network of gravitational wave detection. This strengthen the power of the gravitational wave research.