Even though it is only one atom thick, graphene is 200 times stronger than steel. It conducts heat and electricity with great efficiency, is nearly transparent, and might just be the most useful material ever discovered. The amazing properties of graphene, as well as the many inventions that have spawned from its discovery, are becoming too numerous to count. Now scientists have stumbled upon yet another incredible hallmark of this wonder material: It turns light into motion, reports New Scientist.
This latest graphene breakthrough came entirely by accident. Researchers discovered it while using a laser to cut a sponge made of crumpled sheets of graphene oxide. As the laser cut into the material, it mysteriously propelled forward. Although lasers have been shown to shove single molecules around, they shouldn't be physically capable of moving a structure as large as the graphene sponge.
Baffled, researchers investigated further. The graphene material was put in a vacuum and again shot with a laser. Incredibly, the laser still pushed the sponge forward, and by as much as 40 centimeters. Researchers even got the graphene to move by focusing ordinary sunlight on it with a lens.
How is this possible? Researchers still aren't sure, but there are two leading theories. One explanation is that the material is acting like a solar sail. Basically, photons can transfer momentum to an object and propel it forward, and in the vacuum of space this effect can accumulate and even generate enough thrust to move a spacecraft.
When researchers tested the solar sail theory, however, it worked too well. This led them to consider a second possibility, that the graphene is absorbing the laser's energy, building up a charge of electrons. Eventually extra electrons are released, which act like a propellant, pushing the graphene material in the opposite direction.
Though this second theory is a bit vague and incomplete, scientists were able to detect a current flowing away from the graphene as it was exposed to a laser, suggesting that the theory is at least on the right track.
So what does this all mean? It means that researchers may have just accidentally discovered a propulsion system for a spacecraft that requires no fuel whatsoever. Essentially, a spacecraft built from graphene could explore the heavens powered by nothing more than sunlight.
"While the propulsion force is still smaller than conventional chemical rockets, it is already several orders larger than that from light pressure," wrote researcher Yongsheng Chen and colleagues of the discovery.
More study is required before researchers can say for sure if the material can offer a viable alternative to fuel propulsion, but the results so far are exciting. Truly, there seems to be no end to the amazing qualities of graphene.
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