Physicists are quietly testing wild new theories that treat a hidden fifth dimension as more than science fiction, suggesting it could steer how gravity, dark matter and even cosmic history unfold.

Dark matter could be the result of fermions pushed into a warped fifth dimension. This theory builds on an idea first stated in 1999, but is unique in its findings. Dark matter makes up 75 percent of ...

Up to now, humans have only been able to observe four dimensions in the universe – height, length, width and time. But beyond these dimensions, collectively known as 'spacetime', there may be more ...