Researchers at St. Andrews and the Institute of Scientific Instruments, or ISI, in the Czech Republic have figured out a way of generating an optical field that can reverse the radiation pressure of light.
"The practical applications could be very great, very exciting," Cizmar told the BBC. "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."
"Unfortunately, there is a transfer of energy. On a microscopic scale, that is OK, but on a macro scale, it would cause huge problems," said Cizmar.
"It would result in a massive amount of heating of an object, like a space shuttle. So trapping a spaceship is out of the question."