Physicists in Australia have become the first researchers to levitate a macroscopic object using lasers. The physicists used three lasers to form a levitational “tripod” that could hold a small mirror in free space. Beyond the inherent awesomeness of optical levitation, the physicists believe that the setup could be used as an incredibly accurate sensor for fickle forces such as gravity, and perhaps ameliorating the greatest contradiction of them all: quantum mechanics vs. general relativity.
As you can probably imagine, levitating a physical object with lasers (a stream of massless photons) is rather difficult. “Imagine you’ve got something above you and you are throwing ping pong balls at it to keep it in the air,” is the simple (and not wholly accurate) analogy given by Ben Buchler, one of the physicists involved with the study. The key to the levitation is a force known as radiation pressure, and a branch of physics called optomechanics.
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