The I newspaper today reported that Asier Marzo, an American doctoral student, now a research assistant at Bristol uni, has invented a tractor beam using sound which can be built by anyone with a 3D printer.
The article by Tom Bawden runs
Fans of Star Wars and Star Trek were given a huge boost last year when a doctoral student in America developed the first sonic tractor beam capable of pulling an object towards it by using sound waves. But alas its use was confined to fancy labs with expensive equipment.
Now, thanks to that same individual – who has since become a research assistant at the University of Bristol – it has become far more accessible, at least to anyone with 3D printing technology.
The tractor beam has long been a staple of science fiction, used in a series of Star Trek episodes to capture and tow other space ships, while the Death Star’s tractor beam memorably catches the Millennium Falcon in Star Wars.
A do-it-yourself handheld acoustic tractor beam will now become widely available, according to a new paper published in the journal Applied Physics Letters.
“Previously we developed a tractor beam, but it was very complicated and pricey because it required a phase array, which is a complex electronic system,” said Asier Marzo, the researcher behind the developments.
“Now, we have made a simple, static tractor beam that only requires a static piece of matter,” he said.
“We can modulate a simple wave using what’s called a metamaterial, which is basically a piece of matter with lots of tubes of different lengths. The sound passes through these tubes and when it exits the metamaterial it has the correct phases to create a tractor beam.”
With an effect that is determined by the shape of the tubes, the research team focused on optimising the design to allow fabrication with common 3D printers, ensuring it could be constructed by home hobbyists. (The I, 4th January 2017, p. 23).
I think the pseudoscientific explanation for the tractor beams in Star Trek is that they use gravitons – the subatomic particles that carry the force of gravity – to pull other ships and objects towards them. In an early episode of Star Trek: The Next Generation Wesley Crusher is shown having invented a handheld tractor beam. I think it’s in the episode ‘The Naked Now’.
There are some very clever things now being done with sound. There was a piece on The One Show or perhaps the Beeb’s pop science programme, Bang Goes The Theory, where they showed how sound waves could be used to levitate a series of small objects. I have a feeling it was the discovery of acoustic levitation back in the 1990s or early 2000s that inspired one episode of Far Scape, ‘Taking the Stone’ where Chiana joins a group of alien thrill seekers. These young people get their kicks from leaping off a cliff above an alien echo chamber while humming. If they get the tone right, the sound waves resonate and break their fall. If they don’t, they plunge to their deaths. I can’t imagine that ever catching on as sport in real life, but you never know.