I saw an article last night about gravitational waves, that a black hole merger was detected by not just the Laser Interferometer Gravitational Wave Observatory (LIGO), but by another project altogether, the Virgo collaboration.  This is the first gravitational wave detection confirmed by two separate groups, and it marks the beginning of a new era of experimental science, the first in astronomy in over two decades. Around 1.8 Billion years ago, to black holes merged in a faroff galaxy.  They had masses of 31 and 25 times that of the Sun, though with their incredible density they would each be...