It's unlikely to occur by swallowing a pill or donning a special cloak, but invisibility could be possible in the not too distant future, according to research published on Monday. Harry Potter accomplished it with his magic cloak. H.G. Wells' Invisible Man swallowed a substance that made him transparent. But Dr Ulf Leonhardt, a theoretical physicist at St Andrews University in Scotland, believes the most plausible example is the Invisible Woman, one of the Marvel Comics superheroes in the "Fantastic Four."

"She guides light around her using a force field in this cartoon. This is what could be done in practice," Leonhardt told Reuters in an interview. "That comes closest to what engineers will probably be able to do in the future." Invisibility is an optical illusion that the object or person is not there. Leonhardt uses the example of water circling around a stone. The water flows in, swirls around the stone and then leaves as if nothing was there.

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In the research published in the New Journal of Physics, Leonhardt described the physics of theoretical devices that could create invisibility. It is a follow-up paper to an earlier study published in the journal Science. "What the Invisible Woman does is curve space around herself to bend light. What these devices would do is to mimic that curved space," he said.

Although the devices are still theoretical, Leonhardt said scientists are making advances in metamaterials -- artificial materials with unusual properties that could be used to make invisibility devices.