S&F_scienzaefilosofia.it (Dec 2017)
L’astronomia gravitazionale: in ascolto dei sussurri dell’universo
Abstract
Gravitational astronomy: listening to the whispers of the universe It was about 10 am, Greenwich time, on September 14th 2015 when scientists detected something which had never been detected before: the “sound” of two colliding black holes which, after orbiting around each other for billion years, approached closer and closer until colliding, giving rise to a single huge black hole. A tiny fraction of second before the collision, they sent a signal towards the rest of the universe, their “swansong”, a vibration which propagated in space and time at the speed of light, getting to the Earth 1.4 billion years later. A gravitational wave. A hundred years after the publication of the General Relativity, the Gravitational Waves detection confirms once again the validity of Einstein’s Theory, and paves the way for a completely new research field. Space-time ripples poorly interacting with matter and giving rise to extremely tiny effects, Gravitational Waves need very sophisticated instruments to be detected. In this paper we will retrace the history of this discovery, starting from the breath of revolution of General Relativity which carries along the theorization of Gravitational Wave. We will then go through the analysis of the effect that Gravitational Waves induce on the matter, and we will describe the basic principles of the instrument which detected them, to finally get to the first discovery which opens the way to a completely new era for astronomy.
