Vindication of Albert Einstein’s theory of general relativity, unveiled a century ago. Indeed it is: among the theory’s predictions was that violent events in the universe involving immense masses – such as the collision and merging of two black holes – could set the fabric of spacetime ringing, the ripples spreading across the cosmos and stretching or squeezing space as they pass.
Experiments at the Advanced Laser Interferometer Gravitational-Wave Observatory facilities in Washington and Louisiana have detected these distortions, and it’s a tremendous, exhilarating moment for science. But it’s been barely noted what a deeply strange, perhaps unprecedented situation this is too. The initial detection event happened last September, in the centenary year of the publication of Einstein’s theory. Yet the theory of general relativity itself is a great rarity in science: for this was not an idea motivated by any need to explain observations, but the result of Albert Einstein simply sitting down and thinking. It isn’t easy to find another example of such a rich, fertile theory conjured, as it were, out of nothing.
No one was demanding a new theory of gravity in 1915. We already had one – devised by Isaac Newton more than two centuries earlier – and it seemed to work fine. Sure, there were a few little puzzles, such as the anomalous motion of the planet Mercury. But these weren’t in any sense the stimulus for the new theory (even though it explained them). No, it arose because Einstein saw the world differently.