Physicists have Built a Tractor BeamWell, we've officially done it. We've conquered yet another classic sci-fi staple, brought the impossible to life. Behold: the tractor beam.
The theoretical possibility of what are known as Bessel beams have been known for a while. Like, these beams were posed hypothetically over 100 years ago by a guy by the name of Friedrich Bessel. We even wrote about them a bit ago, when some more development came to light. But until now, they had never been demonstrated. That has been changed thanks to groundbreaking work done by physicists David Ruffner and David Grier.
The key to how a Bessel beam works relies on a unique trait of the Bessel beam: thanks to some clever trickery, these beams reestablish themselves on the other side of objects. Then the light can apply force to move the object backwards in an optical cavity.
Okay, now for the bad news: as the technology stands right now, we won't be able to move anything outside of the microscale. This experiment, Ruffner and Grier's experiment, for example, involved moving a 30 micrometer silica sphere across a surface of water. Remember: we're still talking about moving things with light, and light doesn't exactly exert much force.
But Ruffner and Grier were able to demonstrate a fair amount of control, pulling and pushing the sphere on demand. Not only that, they could layer multiple of these to move things around in three dimensions.
So yeah, right now this tractor beam won't be moving anything but small objects, and will likely stay more of a novelty than a real, viable tool. But, I mean, really. It's a tractor beam. Tell me you thought that it was possible. I say give it a few decades of development and then we'll revisit that size constraint.