Q&A: Black Holes

Q:
Regarding the recently publicized discovery of two black holes in the same galaxy: I wonder if the gravitational waves expected to be generated by these objects have already reached Earth? How fast do gravitational waves travel?

A:
No, the gravitational waves anticipated from the merger of two black holes in NGC 6240 have not yet reached Earth. Electromagnetic waves and gravitational waves travel at the same speed - the speed of light.