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 ...

Physicists know that something unseen is sculpting the cosmos, outweighing ordinary matter by roughly a factor of five, yet every detector built so far has come up empty. One of the most audacious ...

A subatomic particle called the muon is wobbling far more than leading physics models can explain. Its unusual behavior could be evidence of a fifth force of nature or a new dimension. Scientists ...