What do solar panels and Blu-ray discs have in common? Quite a bit, as it turns out. Researchers at Northwestern University have discovered an unexpected yet useful purpose for old Blu-ray discs. It just so happens that the nanoscopic pits and grooves found on Blu-ray discs - the same ones responsible for that vibrant hue - can have a profound impact on a solar panel's efficiency.

To come to that conclusion, researchers gathered up several copies of Police Story 3: Super Cop (any Blu-ray will do, these just happened to be on sale at Best Buy at the time) and created stamps by pouring liquid plastic onto the discs.

The stamps were then pressed into the surface of new solar panels to replicate the pits and grooves. After months of experimenting, the team concluded that the panels stamped with the Blu-ray mold increased light absorption by 20 percent.

As evident by the experiments, a solar panel's surface can play a huge role in how efficient it will ultimately be. Earlier studies have shown that the best surface patters are quasi-random - patterns that aren't completely random but also not entirely uniform.

The patterns on Blu-ray discs happen to be an excellent fit for solar cells, an unexpected result, the researchers said.

Now, if we can just figure out what to do with all of those old VHS tapes.