A tractor beam is a technique that uses a light beam to attract one object to another from a distance. The term was originally coined by E. E. Smith as an update to his earlier description of the attractor beam in his novel Spacehounds of IPC (1931). A reversible tractor beam is a beam that can both attract and repel objects across distances. Scientists have developed versatile reversible tractor beams using a single laser beam to move objects across distances 100 times farther than previously possible. Practical applications could include controlling atmospheric pollution, or retrieving tiny, delicate or dangerous particles for sampling. It could also be scaled up for larger uses.