From WIKI, In February 2007, GRB 070201, a short gamma-ray burst, arrived at Earth from the direction of the Andromeda Galaxy, a nearby galaxy. The prevailing explanation of most short gamma-ray bursts is the merger of a neutron star with either a neutron star or black hole. LIGO reported a non-detection for GRB 070201, ruling out a merger at the distance of Andromeda with high confidence How can a none detection rule out anything, it may be that the detector was not working? If a gravitational wave was not detected may be there are none to be detected. I know that advanced LIGO will not be online until 2014 so what will happen if this new LIGO has null results? I find it hard to imagine space ringing like a bell as some one once said, it seems in my humble opinion to be none intuitive .