Whenever a star ship was in distress, the Star Trek Enterprise could activate its tractor beam and drag the vessel to safety. And now, the technology is gradually moving out of the realm of science fiction and into reality. Scottish scientists claim to have created the most powerful version of a tractor beam to date using the power of sound. While it can’t compete with Star Trek, the beam pulls with a billion times more force and can tow objects a million times larger than previous designs for tractor beams It has been created by Dundee University physicists and uses ultrasound energy to pull a hollow triangular object towards the energy source.
Dr Christine Demore, of the university’s Institute For Medical Science and Technology (IMSAT), said: ‘We were able to show that you could exert sufficient force on an object around 1cm (about 0.4in) in size to hold or move it, by directing twin beams of energy from the ultrasound array towards the back of the object.’ The team, writing in the journal APS Physics, used an ultrasound device that is already clinically approved for use in MRI-guided focused ultrasound surgery. The researchers have previously demonstrated another piece of sci-fi technology – Dr Who’s sonic screwdriver – could be created using a similar ultrasound array. They used the acoustic beam to both push away an object in its path and cause it to rotate.
Dr Demore said: ‘The concept has been there for a long time. ‘It took a couple of years to find the right pieces and get them together, with lots of other research going on. ‘Our previous work on the sonic screwdriver led to this.’
The latest experiment was carried out using a suspended triangular prism, a little denser than water, and about 5cm (2in) tall. Dr Demore said: ‘We can do other shapes and sizes, but it was the best shape to demonstrate what was happening.’ Although their work has caught the interest of sci-fi fans, it has significant potential for ultrasound-based clinical techniques.