The tractor beam in Star Wars could grab objects like spaceships remotely. Though the technology was a science fiction, researchers have turned it into reality. A team of scientists at the Universities of Bristol and Sussex in the UK and Spain’s Public University of Navarre have built a device that can remotely move and levitate objects using sound waves. Findings of the study were published in the journal Nature Communications.
The tractor beam moves 4mm plastic bead
The tractor beam uses high-amplitude sound waves to manipulate objects in mid-air and defy gravity, said Sriram Subramanian of the University of Sussex. Using high-intensity, high-pitched sound produced by “64 miniature loudspeakers” that create an acoustic hologram, scientists were able to move, levitate, and rotate small objects without touching them by controlling the audio output.
Sound waves exert significant forces on objects. In tests, researchers controlled a spherical bead made of a light plastic called polystyrene. The bead measured only 4mm in diameter. The tractor beam used sound waves at a frequency of 40 kilohertz. Professor Bruce Drinkwater of Bristol University said the sound has been controlled to a degree never achieved before.
Scientists developing different variants of tractor beam
The sound waves took the form of a cage to surround the spherical bead and hold it in place, a vortex to hold the levitating object, and that of tweezers to lift the bead. Multiple waves interfere with each other to create acoustic 3D shapes that exert forces from all directions to keep the object in place. The tractor beam was created with the help of a company called Ultrahaptics, which was co-founded by Professor Sriram Subramanian.
The team is currently working on different variants of the technology, including a larger tractor beam that could levitate even soccer balls from a distance of up to 30 feet. They are also creating a smaller version that could have medical applications. It would be used in manipulating particles inside the human body such as kidney stones, clots, cells, and drug capsules without any incision.