STORY – These very large gravitational waves are emitted by the mergers of supermassive black holes.
This is Albert Einstein’s great discovery: the Universe is not simply the sum of the objects that compose it. It has an underlying structure, the famous space-time, which is both plastic and dynamic. Its best known property is to be deformed by mass. Popularizers readily use a two-dimensional analogy to get an idea of this: that of a stretched sheet on which more or less heavy objects are placed, which then form basins. This makes it possible to instinctively understand why a ball thrown straight on the sheet will naturally be deflected from its trajectory by a massive object. In Einstein’s vision, the object goes straight, it is the space in which it evolves which is deformed and modifies its apparent direction.
But this is not the only consequence of the theory of general relativity. There are at least two others: space-time evolves (it is in accelerated expansion which leads all objects to move away from each other…