"General relativity predicts that disturbances in the gravitational field propagate as gravitational waves, and that low-amplitude gravitational waves travel at the speed of light." It seems high energy waves may travel slower, but certainly not faster. So, a large star whilst going supernova can still emit gravitational waves. OK. But once the black hole forms, the escape velocity inside the Schwartzschild radius is greater than c, so Einstein says the gravitational waves cannot exit (they travel at c.) If this is the case, the gravitational effects of a blackhole could never exceed the critical limit that made the Schwartzschild radius in the first place. So, why the supermassive black hole at the centre of galaxies with ~1 billion solar masses? Are we postulating that it all formed at once rather than accreting over billennia? Why is a super-massive black hole different from other black holes? It seems black holes have hair, and the hairstyle changes as they accrete further mass. So, gravitons (if they even exist) must travel faster than c. Discuss. Is space-time far more fundamental than c? Maybe there are no gravitons. It seems space-time is a fundamental building-block of the universe, separate from radiation. Grand-unification is, after all, only a wish of some physicists. We should find that c is an effect of space-time and the amount of mass within it.