Those of us who are Star Trek and Star Wars fans know what a tractor beam is. But for the uninitiated, here's a succinct definition:
"[A] hypothetical device with the ability to attract one object to another from a distance."
Here's what a tractor beam looks like on Star Trek:
And apparently they aren't so hypothetical anymore.
Researchers at the Australian National University have figured it out... to a point. Utilizing a specially designed hollow laser beam, researchers have been able to move very small particles for a distance of up to a meter and a half.
This hollow beam traps light-absorbing particles in what the researchers call a "dark core." They then move these particles up and down the light beam-sort of like a little spaceship floating through a tunnel.
The movement of air molecules around the particles creates this movement. These molecules angle one side of the particle closer to the laser wall-which simultaneously pulls the other side of the particle farther away from the wall. This creates thrust (in this case known as "photophoretic force) that pushes the particle back towards the center of the hollow beam. This same thrust causes the particle to move forward in the pipeline. Its sort of like a micro version of bumper cars.
The real gadget looks like this:
If I understand correctly, that tiny dot in between the lasers and reflectors would be the particle. But dust-sized particles aren't quite as visually dynamic as a starship. And while this little tractor beam is in no way as exciting to look at as this-
-its still pretty damn cool, primarily because there are already ideas for practical applications of this technology. All of these deal with quite tiny little particles, of course. Some of the ideas involve directing and clustering of nano-particles, the sampling of aerosols in the atmosphere, and the handling of sample materials without the necessity of physical contact. The handling of potentially hazardous microscopic materials is also being considered-which makes a great deal of sense if the tractor beam is a stabilized transportation source.
Researchers are still a long way from towing spaceships through the galactic void-like this:
But it looks like they're finally on the track. And until then, it sounds like the potential uses of this technology may open up a whole new realm of techniques in the scientific study of a variety of extremely small particles.
SOURCES: Wikipedia, Memory Alpha