# How does detection of Gravitational Waves affect Quantum Gravity Research?

After detection of gravitational waves in 2015, what are it's implications on quantum gravity theories? Are there any quantum gravity predictions validated through GW detection?

• Many alternative theories of gravity would lead to the graviton acquiring a mass. If that were the case gravitational waves of different frequencies would travel at different speeds, causing the shape of a gravitational wave signal to change as it travels through space. No such deformation of the signal is observer allowing us to put an upper bound on the graviton mass of $$4.7\times10^{-23} eV/c^2$$.
• The near simultaneous observation of gravitational waves and electromagnetic waves from the merger of a neutron star binary tells us that gravitational waves travel almost exactly the same speed as light with the relative difference being at most $$10^{-13}$$. (This is smaller than accuracy with which the speed of light can be related to other measures of length under lab conditions!) This has eliminated large classes of alternative theories that would lead to gravitational waves travelling at another speed.