Scientists propose levitating objects with light

Scientists are researching a way to move objects using only light which could open the door to interstellar travel.

Although the research by a team at the California Institute of Technology (Caltech) is still theoretical, its applications could lead to enormous changes.

With funding provided by the US Air Force, researchers believe that the method could be used to develop a spacecraft which could travel to the nearest planet outside our solar system within 20 years - powered only by light.

Their work is described in a paper published in the journal Nature Photonics and was completed in the Harry Atwater laboratory. It proposes using tiny nanoscale patterns of light to move much larger objects. A sheet of paper is about 100,000 nanometres thick.

It is based on research from decades ago, when scientists developed "optical tweezers" which could allow them to manipulate nanoparticles using the pressure from a laser beam.

This kind of research formed the basis for the 2018 Nobel Prize in Physics, but the so-called tweezers were only able to move very small objects very small distances.

Dr Ognjen Ilic, first author in the study, gave an analogy: "One can levitate a ping pong ball using a steady stream of air from a hair dryer.

"But it wouldn't work if the ping pong ball were too big, or if it were too far away from the hair dryer, and so on," he explained.

However the new research means that objects which are metres wide could be manipulated with a light beam.

Image:The technology could allow for interstellar flight, say the researchers

The key is to create a specific tiny pattern on the object's surface, which would interact with the light in such a way as to propel the object to move.

According to the research, the light source doesn't need to be a focused beam, and could be millions of miles away.

"There is an audaciously interesting application to use this technique as a means for propulsion of a new generation of spacecraft" said Professor Harry Atwater, who is also the director of the Joint Center for Artificial Photosynthesis.

"We're a long way from actually doing that, but we are in the process of testing out the principles."

The theory is that such a spacecraft could be covered with these nanoscale pattern structures and then accelerated away from the planet by a laser based on Earth.

Because the spacecraft doesn't need to carry fuel, it could reach speeds close to the speed of light, and possibly travel to other stars.

(SKY NEWS)