Physicists at the Harvard-MIT Center for Ultracold Atoms have figured out a way to make photon particles bind together to form molecules. Photons have typically been thought of as massless particles that don’t interact with each other, and any binding of light particles has only been discussed theoretically. “It’s not an in-apt analogy to compare this to light sabers,” says Mikhail Lukin, Professor of Physics at MIT. “When these photons interact with each other, they’re pushing against and deflect each other. The physics of what’s happening in these molecules is similar to what we see in the movies,” Lukin says. A special type of medium has been created in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. But are light sabers really right around the corner?