The Universe is a vast city. In it, dark matter is the invisible framework of buildings, and dark energy is the force stretching the streets. For a long time they were considered independent, but new research has caught them in secret communication. Astronomers used gravitational lenses — massive clusters of galaxies that bend light like funhouse mirrors at a crossroads. The effect was predicted by Einstein, and Fritz Zwicky was the first to notice that clusters behave as if an invisible mass is hiding within them. The lenses weighed this mass over time and showed: in the past, dark matter was flowing into dark energy, slowing the acceleration. But the most unexpected part — the process wasn't constant. It changed direction several times over cosmic history, as if the city breathed, periodically rearranging its streets and framework.
The discovery equips us with a new way to study the expansion of the universe, which is accelerating for no obvious reason. If dark energy and matter really exchange properties, the cosmic mystery becomes a little clearer.
A gravitational lens can create multiple copies of the same galaxy in the sky, like a cosmic trick with mirrors.