To the dismay of "Star Wars" fans everywhere, physicists have long cried foul about the science of building real-life lightsabers. According to conventional physics, photons don't behave like regular particles of matter. They are massless particles, and can't interact with one another. It's therefore impossible to build anything out of light with a solid structure, such as a lightsaber.
But a breakthrough new discovery from researchers at the Harvard-MIT Center for Ultracold Atoms could change everything, according to phys.org (link provided below). They have discovered how to make individual photons interact and bind together into molecular structures. Not only does this represent a whole new state of matter, but these light molecules can potentially be shaped to form solid structures — in other words, lightsabers!