We largely think of the world in four dimensions — time and the three spatial dimensions. But a fifth dimension might actually solve this longstanding mystery.

For the first time, scientists have observed a collection of particles, also known as a quasiparticle, that's massless when moving one direction but has mass in the other direction. The quasiparticle, ...

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 ...