There is an interesting new result in the physics community today, with the possible discovery of a new force that acts on very small objects. This result has just been announcement, and as such it is still far from being independently confirmed, but if it is true then it will have a number of implications for the growing field of nanotechnology.

The new force is being called the lateral Casimir effect, and appears to be a variation on the well known Casimir force that affects other nanoscale objects.

According the laws of quantum mechanics, empty space is not empty. Even the most remote regions of space, which are believed to be devoid of matter and energy, will contain subatomic bursts of particles and antiparticles that exist for a fraction of a second. They suddenly appear, and just as suddenly disappear again. The effect of all of these virtual particles is to create a vacuum energy that is always present.

However we can change this vacuum energy in a number of ways. The method that is most relevant to the current discussion is the Casimir effect. If two conducting plates are placed close together, then they restrict the energies and momenta of the virtual particles. In effect, low energy particles can no longer form between the two plates because they do not have enough room to exist. (It should be recalled here that in quantum mechanics, the position of a particles is not able to be defined precisely, but rather each particle exists as a sort of diffuse cloud. And if a region of space is smaller than this cloud, the particle will not exist in that region.).

And this in turn leads to a measurable effect. Because a small region contains less virtual particles than a larger region, it will also have a lower energy density. And as we know from basic physics, forces acts to minimize energy.  The virtual particles on one side of each plate will push against the plate, and the lower density of virtual particles between the two plates is not sufficient to balance it out. The net result is that the two plates will try to pull themselves closer together, creating the Casimir force.

This new discovery takes that effect one step further. The new claim is that if one of the plates is replaced with a tiny sphere, not only will it still be pulled towards the other plate (which was already known and measured in experiments), but if it is rotating then it will also move parallel to the plate and perpendicular to the axis of rotation!

This is not entirely unexpected, but it is still quite interesting. It would seem that a rotating sphere creates more virtual particles on one side than on the other, and that the net effect is to push the sphere sideways. This could have important implications in practical applications, as many teams of scientists and engineers are now designing nanotechnology that operates on this scale. The devices they build will feel this new forces, and additional measures will be required to either account for it or cancel it out.

Of course as always with these announcements, it could also be an experimental glitch or a statistical anomaly and mean nothing at all. However it is an interesting result, and an even more interesting underlying theory.

Sometimes empty regions of nothing can be the most interesting things of all!