Just read the typically excellent articles in Science News on the recent confirmation of gravity waves. The merger of two black holes that triggered the waves that reached earth some 1.3 billion years later converted three solar masses into sufficient energy to send a tiny but measurable ripple to the two LIGO detectors. The total energy released “exceeded that of all the stars in the universe combined.” But as SN notes, the gravity waves did not travel through space – as does light – but as a wave in the fabric of spacetime itself traveling at the speed of light.
It is worth pondering the fact that gravity and light – both seemingly very different types of elementary vectors – both travel at the same finite speed. What is it about the universe that is revealed by the cosmic speed limit of 186,000 miles per second that even gravity obeys?
I've previously suggested that the speed of light measures “our awareness of the distance traveled within spacetime” and that “the speed of light may actually be the speed of consciousness.” At the speed of light, time stops. Someone surfing a photon would be everywhere that photon would ever be at the same moment. We experience the universe as spacetime. We move through it while, in a sense, the universe itself must exist all at once outside space and time. Lots of scientists are looking at ways to use string theory or supersymmetry, positing extra dimensions and multiple universes, to try to explain our universe through what might seem an updated version of efforts to find how many angels can dance on the head of a pin. (Regrets to St Thomas, whom I follow in the thought that when you reach the end of reason, it's a finger pointing to god.) But these efforts beg a question: whatever theory they come up with, why would the cosmos be that way? Reality may not be an infinitely peel-able onion. The fact remains that we live in a universe where even gravity takes time to travel as perceived by us. (I suppose a surfer riding that gravity wave would also be everywhere that four-dimension wave would be at the very same moment.)
Why ask what all this means? The notion of deriving meaning from the fact that we exist and in a world that seems perfect for us is basic to humanity. But beyond this, facing up to these questions may be the way forward to a new science. This would not mean abandoning quantum physics and relativity but thinking our way through them without trying to find dancing angels.