Scientists announced recently that they have discovered a new form of light, one that breaks a fundamental understanding of physics, and could lead to faster fiber-optic cables.
Let’s first start, though, with the physics concept of momentum, which is what you get when you multiply an object’s mass and velocity. Momentum can go in many different directions, of course. Angular momentum, specifically, describes the movement of objects, like the Earth, that move in circles, both figuratively and literally.
Light photons, which tend to spin as they travel through the universe, also have a particular angular momentum, and, until recently, scientists thought that the value of that momentum would always be a whole integer multiple of Planck’s constant. A whole number, in other words, not a fraction.
But a team of Irish scientists—who were actually trying to improve optical communications—recently stumbled upon a form of light that had angular momentum that wasn’t a whole number. This was new! And startling, in part because light and its photons are among the things scientists study the most.
“What I think is so exciting about this result is that even this fundamental property of light, that physicists have always thought was fixed, can be changed,” said Paul Eastham, a scientist who was part of the discovery.