Tractor beam

A tractor beam is a device with the ability to attract one object to another from a distance. The concept originates in fiction: the term was coined by E. E. Smith (an update of his earlier "attractor beam") in his novel Spacehounds of IPC (1931). Since the 1990s, technology and research has laboured to make it a reality, and have had some success on a microscopic level. Another method to realize tractor beams is based on the use of biaxial birefringent media. Less commonly, a similar beam that repels is called a pressor beam or repulsor beam. Gravity impulse and gravity propulsion beams are traditionally areas of research from fringe physics that coincide with the concepts of tractor and repulsor beams.