Catching cosmic chirps

THE faint “chirp” lasted just one-fifth of a second. But the feeble signal, picked up by sophisticated detectors situated in two different geographical locations in the United States about two years ago, has given scientists enough evidence of the existence of the elusive gravitational waves, predicted by Albert Einstein about a century ago. Weiss and Thorne are pioneers who firmly believed that the detection of gravitational waves was possible and have made serious efforts to do so since the mid 1970s, and Barish successfully set up the LIGO detectors outside Hanford, Washington, in the north-west of the U.S., and in Livingston, in the southern State of Louisiana. Apart from being the first ever observation of gravitational waves, it indicated for the first time the existence of medium-sized black holes, which have 30 to 60 times the mass of the sun, that they could merge by colliding with each other, and that the gravitational radiation released at the time of the collision could be so powerful that it could surpass the light of all the stars in the visible universe. According to Einstein, space and time are malleable, and the combined four-dimensional space-time vibrates with gravitational waves that are created when a mass accelerates—like when an ice skater pirouettes, a star explodes in a distant galaxy, or two black holes rotate around each other.