Scientists at Cornell University have done the impossible: they've managed to bend space time to hide an entire event.

It's not exactly invisibility but what the scientists at Cornell have done is equally fantastic. The idea behind the space-time cloak is to make an entire event undetectable by light. The temporal cloak will only hide an event for an incredibly tiny fraction of a second, about 40 trillionths of a second but during that time frame objects are invisible and events are unrecorded. For instance, a person could run from one location to another but with the temporal cloak a video recording will only see the person move instantaneously from point A to point B.

Other researchers have created invisibility cloaks that bend light in the traditional three dimensions. With the Cornell temporal cloak, the speed of the light beam is altered changing how it interacts with objects. If something can happen that can leave the light undisturbed then the event can become invisible.

"You kind of create a hole in time where an event takes place," said study co-author Alexander Gaeta, director of Cornell's School of Applied and Engineering Physics. "You just don't know that anything ever happened."

Gaeta's team used devices called "split-time" lenses, which slows down part of a light beam and then speeds up another part to create a gap in the beam. Anything in that little gap will be invisible to anyone observing. The researchers have been able to control light to essentially mask an event in time.

The researchers have only been able to mask about 40 trillionths of a second but Gaeta predicts his group will be able to expand that to tens of nanoseconds. This is far too fast to create a temporal cloak that can hide would-be thieves from security cameras. Even if the technology were to improve in the future, temporal cloaks wouldn't be able to hide a person for more than minutes or even seconds.

"Whilst sophisticated methods exist to 'slow' light down, these would need to be combined with even more sophisticated methods to modulate its speed at different places at different times," said Martin McCall, a professor of theoretical optics at Imperial College in London who first theorized the concept.

"I can't rule it out, but it represents a level of sophistication that we cannot approach with current technology."

There are other applications for this technology in optoelectronic circuits and communications. Not as amazing as an actual invisibility cloak but still quite a remarkable scientific discovery.