You may be familiar with Tractor beams as they are extremely popular amongst Science-Fiction movies, however they may not be fiction forever as it seems Chinese researchers have discovered how they work exactly.
The researchers from Fudan University in Shanghai figured out on a nanoscopic level that turning a laser beam inside out generates a backward pull force for the forward travelling protons. As this discovery has only been made at such a small scale level, the prospect of being able to dock spaceships into space bases is still very much future technology it seems.
The way in which all of this works is basically using momentum. Near the beginning of the 20th century Peter Lebedev and Arthur Compton found that photons have a small amount of momentum that engages anything it hits. We already know that photons can push things like solar sails and electrons.
In order to reverse this process, the beam’s forward momentum cannot be too great so must be small enough and the photons must scatter at just the right angle by exciting ‘multipoles within the particle’ it’s hoping to move.
As Technology Review report, all this is very good in theory but Jun Chen and his fellow scientist must now demonstrate that it works. What do you think of this breakthrough? Will we ever see larger objects being pulled in a Tractor beam? Let us know what you think.
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