Gingerino: the Gran Sasso experiment that studies Earth’s rotation and the effects on earthquakes
The heart of the Gingerino (Gyroscopes in General Relativity) experiment is a laser gyroscope, a sort of “spinning top of light”, which can measure each small difference in the planet’s rotation with high precision that can reveal fluctuations provided by Einstein’s general theory of relativity. Thanks to this technology, the Gingerino experiment, developed by the Italian National Institute of Nuclear Physics (INFN) and housed 1,400 metres deep within the mountain at the Gran Sasso National Laboratory (LNGS), could also have important implications for the study of soil geology and earthquakes.
All rotating bodies, including our planet, produce distortions in the space-time: it is an effect called Lense-Thirring effect that, although almost impossible to detect, could have consequences on Einstein’s general theory of relativity. The Gingerino experiment aims to measure with great accuracy the speed of rotation of the Earth and its possible effects through two laser beams running in opposite directions along the sides of a square 3.6 metres in sidelength, made of several perfectly smooth mirrors. The device is anchored to the rock of the mountain, far from any external forces.
‘This prototype – explained Angela Di Virgilio from the INFN, coordinator of the experiment – is necessary to carry out the most powerful and sophisticated final Ginger experiment in the future. The detector that we have developed so far has turned out to be extremely sensitive as well as robust, that is, it can run for months without the need for any kind of intervention’.
The first data from Gingerino were published in the journal Review of Scientific Instruments and will be used to verify the correctness of what predicted by Einstein also in many other sectors. As a stethoscope sensitive to any change in the Earth’s heartbeat, the experiment in the heart of the Gran Sasso could help understand some mechanisms that take place inside the planet. With the experiment, for example, it has been possible to acquire information on the rotational ground motions induced by earthquakes, which will help understand how seismic waves travel through the Earth's crust and how this is deformed: these data are essential to design anti-seismic buildings and infrastructure.