According to a well-known theory in quantum physics, a particle’s behavior changes depending on whether there is an observer or not. It basically suggests that reality is a kind of illusion and exists only when we are looking at it.
Picture a colossal empire of little houses stacked on top of each other. Visualize them connected by staircases snaking under dangling wires, through corridors so dark even police were rumored to be afraid of them.
For years, physicists have attempted to explain dark energy – a mysterious influence that pushes space apart faster than gravity can pull the things in it together. But physics isn’t always about figuring out what things are. A lot of it is figuring out what things cause.