‘Spacetime cloak’ can make time travel possible

LONDON - A ’spacetime cloak’ may be straight out of science fiction, but some day it might permit time travel or change history.

A ‘cloaked’ individual could, for instance, travel from one place to another while appearing to vanish and appear instantaneously in a new location.

The device would speed up and slow down light to give the illusion that events have just not happened, according to the Journal of Optics.

For instance, a scientifically-savvy thief with access to technology could open a safe, empty its contents, and escape right under the watchful eye of a surveillance camera, reports the Daily Mail.

The video footage would show that the safe door was closed all the time. Scientists at Imperial College London have proved it could work in theory by adapting standard fibreoptic technology.

Lead scientist Martin McCall said: “We have shown that by manipulating the way the light illuminating an event reaches the viewer, it is possible to hide the passage of time.”

“If you had someone moving along the corridor, it would appear to a distant observer as if they had relocated instantaneously, creating the illusion of a Star Trek transporter. So, theoretically, this person might be able to do something and you wouldn’t notice,” McCall added.

The new research goes a step beyond ‘invisibility cloak’ technology by devising a way to conceal events as well as objects. This is achieved not by bending light, but by manipulating the speed at which light travels through a material medium.

Illuminating light is divided into an accelerated ‘leading part’ which arrives before an event, and a slowed ‘trailing half’ which lags behind and arrives after the event.

Both the fast and slow rays are joined back together and adjusted to the same speed before being seen by an observer.

The result is a concealed passage of time or ‘temporal void’ during which the event is not illuminated and goes unnoticed.

Graduate student Alberto Favaro, who also worked on the project, said: “It is unlike ordinary cloaking devices because it does not attempt to divert light around an object.”