Did you know a cheap red laser pointer is good for more than just annoying people at the cinema? As YouTube’s Styropyro, aka Drake Anthony, demonstrates, by focusing the beam you can actually use it to lift and levitate tiny specs of diamond dust, similar to how Star Trek’s tractor beams seemingly work.
The science behind this experiment earned physicist Steven Chu the Nobel Prize in Physics back in 1997, but you don’t need a dedicated MIT research lab to try it yourself. You just need roughly £15 in parts, including a lens to focus the laser diode, and a room without any air currents because the focused beam of light doesn’t have the strongest grasp on the particles it traps.
So how does a beam of light you can’t really feel lift an object? Anthony does a good job explaining the science in his video, but it’s an effect called optical levitation where the momentum of photons is transferred to an object, trapping it in a beam of light. The object has to be incredibly small, less than 50 micrometres in diameter, for the experiment to work, which means that you unfortunately won’t be trapping any passing spaceships by pointing your laser pointer towards the stars. [YouTube]