# Scientists can levitate stuff and make it fly around using sound

Japanese scientists have made hundreds of tiny plastic balls float around like miniature spaceships.

Today’s news from the world of Awesome Science comes from the University of Tokyo, where a team has been levitating and controlling objects using sound. Here’s the video:

As the video points out at the beginning, levitation of objects using sound has been around for a few years. If you’ve ever stood in front of a large speaker you’ll know that they can pump out what feels like quite a forceful blast of air as they vibrate - but, somewhat deceptively, that’s not quite the whole story.

Rather than physically push air out from the speaker, what you’re experiencing is a wave of compression moving through the air. The speaker compresses a packet of air, which then “rolls” through the room, with the size of the compressed air corresponding the wavelength of the sound wave. And, just like sound waves, waves that overlap each other create new waves.

To levitate something just requires creating a standing wave. Think of it like this - if you’re watching a sound wave plotted out on a graph, it’ll be rolling along, going up and down as it oscillates. A standing wave occurs when two or more waves combine to create a new wave where, as the wave oscillates, there are points where there’s no movement. They’re called nodes.

Here’s a gif to illustrate how that works. The blue and green waves are combining to create the red wave, which has those points on the central axis that aren’t moving:

(Image: Wikimedia Commons)

If a speaker outputs a standing wave, in the most basic sense it means that it won’t feel like the areas of compression - those blasts of air - are moving. The gaps between those blasts of air will be positions of neutral force, with air pressure pushing in on it from both directions. If you stick an object in there that’s light enough, and smaller that the size the gap (which will be the sound’s wavelength), the force of the air should keep it floating in a stable position.

What the Tokyo University team has done is build upon that idea, by combining sound waves in three dimensions. The video shows not just tiny little plastic balls being levitated and controlled, but also resistors, LEDs, screws, bolts, and other small items. Rhett Allain at Wired worked out that you could levitate anything both smaller than 8mm and less dense than 1,000kg/m3, which is tiny - but it does have practical applications, particularly when people are working with sterile things they want to move but can't touch, like spaceship parts or medicines.

Ian Steadman is a staff science and technology writer at the New Statesman. He is on Twitter as @iansteadman.

Photo: Getty
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# Move objects with your mind – telekinesis is coming to a human brain near you

If a user puts on the Neurable headset, they can move virtual objects with their thoughts.

On 30 July, a blog post on Medium by Michael Thompson, the vice-president of Boston-based start-up Neurable, said his company had perfected a kind of technology which would be “redrawing the boundaries of human experience”.

Neurable had just fulfilled the pipe dreams of science fiction enthusiasts and video game fanboys, according to Thompson – it had created a telekinetic EEG strap. In plain English, if a user puts on the Neurable headset, and plays a specially-designed virtual reality video game, they can move virtual objects with their thoughts.

Madrid-based gaming company eStudioFuture collaborated with Neurable to create the game, Awakening. In it, the user breaks out of a government lab, battles robots and interacts with objects around them, all hands-free with Neurable's headset. Awakening debuted at SIGGRAPH, a computer graphics conference in Boston, where it was well received by consumers and investors alike.

The strap (or peripheral, as it’s referred to) works by modifying the industry standard headset of oversized goggles. Neurable's addition has a comb-like structure that reaches past your hair to make contact with the scalp, then detects brain activity via electroencephalogram (EEG) sensors. These detect specific kinds of neural signals. Thanks to a combination of machine-learning software and eye-tracking technology, all the user of the headset has to do is think the word “grab”, and that object will move – for example, throwing a box at the robot trying to stop you from breaking out of a government lab.

The current conversation around virtual reality, and technologies like it, lurches between optimism and cynicism. Critics have highlighted the narrow range of uses that the current technology is aimed at (think fun facial filters on Snapchat). But after the debut of virtual reality headsets Oculus Rift and HTC Vive at 2016’s Game Developers conference, entrepreneurs are increasingly taking notice of virtual reality's potential to make everyday life more convenient.

Tech giants such as Microsoft, Facebook and Google have all been in on the game since as far back as 2014, when Facebook bought Oculus (of Oculus Rift). Then, in 2016, Nintendo and Niantic (an off-shoot from Google) launched Pokémon Go. One of Microsoft’s leading technical fellows, Alex Kipman, told Polygon that distinctions between virtual reality, augmented reality and mixed reality were arbitrary: "At the end of the day, it’s all on a continuum."

Oculus’s Jason Rubin has emphasised the potential that VR has to make human life that much more interesting or efficient. Say that you're undergoing a home renovation – potentially, with VR technology, you could pop on your headset and see a hologram of your living room. You could move your virtual furniture around with minimal effort, and then do exactly the same in reality – in half the time and effort. IKEA already offers a similar service in store – imagine being able to do it yourself.

Any kind of experience that is in part virtual reality – from video games to online tours of holiday destinations to interactive displays at museums – will become much more immersive.

Microsoft’s Hololens is already being trialled at University College London Hospital, where students can study detailed holograms of organs, and patients can get an in-depth look at their insides projected in front of them (Hololens won’t be commercially available for a while.) Neurable's ambitions go beyond video games – its headset was designed by neuroscientists who had spent years working in neurotechnology. It offers the potential for important scientific and technological breakthroughs in areas such as prosthetic limbs.

Whether it was a childhood obsession with Star Wars or out of sheer laziness, as a society, we remain fascinated by the thought of being able to move objects with our minds. But in actual realityVR and similar technologies bring with them a set of prickly questions.

Will students at well-funded schools be able to get a more in-depth look at topography in a geography lesson through VR headsets than their counterparts elsewhere? Would companies be able to maintain a grip on what people do in virtual reality, or would people eventually start to make their own (there are already plenty of DIY tutorials on the internet)? Will governments be able to regulate and monitor the use of insidious technology like augmented reality or mixed reality, and make sure that it doesn't become potentially harmful to minors or infringe on privacy rights?

Worldwide spending on items such as virtual reality headsets and games is forecast to double every year until 2021, according to recent figures. Industry experts and innovators tend to agree that it remains extremely unlikely you’ll walk into someone examining a hologram on the street. All the same, VR technology like Neurable’s is slowly creeping into the fabric of our lived environment.