How does Ligo know which event causes the waves it detects?

Question

I heard that one of the first waves it detected was from two black holes colliding, but how do the scientists know that it was that particular event, in that part of space, at that time in the past?

In: Physics

Answer 1

Each LIGO antenna has two arms at right angles; this gives a partial answer to the question of which direction the signal came from. Every additional LIGO antenna further cuts down the possible directions, since they are necessarily in different orientations. (How many are there? I forget.)

Also, the time between the signal’s arrival at two stations gives the angle between the line from the source to Earth and the line between the stations.