“Speed” of Gravity and Speed of Light
I'm wondering if gravitational waves have the same speed of light? They must if gravity is mediated by a graviton spin 2 massless boson. One can argue that since gravity is a long range force, then its boson must have zero mass. But neutrinos travel through the universe too and despite their tiny mass yet have non zero mass. So, I'm wondering if there is a deeper justification for believing that gravity's speed =c?