In another step forward for the rapidly expanding universe of invisible astronomy, scientists said on Wednesday that on Aug. 14 they had recorded the space-time reverberations known as gravitational waves from the collision of a pair of black holes 1.8 billion light years away from here.
It was the fourth time, officially, in the last two years that astronomers have detected such ripples from the cataclysmic mergers of black holes – objects so dense that space and time are wrapped around them like a glove so that not even light can escape.
In the August event, one black hole with about 31 times the mass of the Sun and another with 25 solar masses, combined to make a hole of 53 solar masses. The remaining three solar masses were converted into gravitational waves that radiated more energy than all the stars in the known universe. The observation is in line with earlier gravitational wave detections, confirming an evolving view of the cosmic night.
The detection, announced at a G7 meeting of science ministers in Turin, Italy, and in a paper in the journal Physical Review Letters, marked the successful debut of a new gravitational wave detector known as Virgo, built by a European collaboration and located in Cascina, close to Pisa, Italy.
The first detections of gravitational waves had been made by a pair of L-shaped antennas, called LIGO, in Hanford, Wash. and Livingston, La., which…