Star Trek style 'tractor beam' created by scientists

A real-life "tractor beam", which uses light to attract objects, has been developed by scientists.

It is hoped it could have medical applications by targeting and attracting individual cells.

The research, published in Nature Photonics and led by the University of St Andrews, is limited to moving microscopic particles.

In science fiction programmes such as Star Trek, tractor beams are used to move much more massive objects.

It is not the first time science has aimed to replicate the feat - albeit at smaller scales.

In 2011, researchers from China and Hong Kong showed how it might be done with laser beams of a specific shape - and the US space agency Nasa has even funded a studyto examine how the technique might help with manipulating samples in space.

The new study's lead researcher Dr Tomas Cizmar, research fellow in the School of Medicine at the University of St Andrews, said while the technique is very new, it had huge potential.

He said: "The practical applications could be very great, very exciting. The tractor beam is very selective in the properties of the particles it acts on, so you could pick up specific particles in a mixture."

"Eventually this could be used to separate white blood cells, for example."

Usually when microscopic objects are hit by a beam of light, they are forced along the direction of the beam by the light photons. That radiation force was first identified by the German astronomer Johannes Kepler in 1619 when he observed that tails of comets always point away from the Sun.

Nonprofit group Mars One seeks astronauts to colonize Mars in 2023

A nonprofit organization based in the Netherlands is making plans to establish a human settlement on Mars in 2023 and is in need of astronauts to train and prepare for the mission.

Anyone on Earth can apply if basic requirements are met. Mars One released its application criteria on Tuesday, which includes, among other virtues, "a deep sense of purpose, willingness to build and maintain healthy relationships, the capacity for self-reflection and ability to trust. Candidates must also be adaptable, curious, creative, resilient, and resourceful. Also, they must be at least 18-years-old. No maximum age has been set.

The selection process will commence during the first half of 2013. Mars One experts and viewers of a "global, televised program" will choose from the applications. Those selected will be assembled into teams of four. At least six teams are supposed to be ready to launch in September 2022.