Adrian ChoOutwitting Albert Einstein just got even tougher. More than 100 years ago, the famous physicist published his explanation of gravity, known as general relativity (GR), which successfully explains everything from the orbits of planets to the bending of starlight.
Still, some physicists have been trying to invent theories that can solve puzzles GR cannot—for example, by explaining away the need for invisible dark matter, whose gravity appears to bind the galaxies.