What’s insane is the accuracy.
> Cornish’s team of researchers combined the timings of the first three detections to narrow down the speed of the waves to between 55 and 142 percent of c.
Not too unexpected.
> A small army of physicists used the burst of gamma rays captured from last month’s neutron star collision to come up with their own estimate. Their method was a little more precise. Ok, a whole lot more precise. A match between the speed of light and speed of gavity within -3 × 10^-15 and 7 × 10^-16 of c.
Insane precision.