Editing History
The space-time cloak
L-R: Light travelling through optic fibers. This graphic shows how the "space-time" cloak works
Recently, physicists from the Imperial College London (ICL) conducted a study on manipulating the nature of space and time and concluded that it was possible to hide actual events from the plain sight of the viewer. In other words, an event could take place; say a journey from one location to the other, however, the "journey" in-between, from the point of start to the destined location would remain entirely invisible to the naked eye. Scientists believe this wondrous scientific scheme, which is being referred to as "space-time cloak" can be the ultimate hiding place, like a hole carved right out of space and time. And the very nature of physics, in this particular case, would manipulate light to such an extent that the actual events in real life would be "cut off", just as an editor cuts off scenes from the reel of film that s/he does not want public to watch. This means that this space-time cloak theory is actually based on censoring the flow of events that we generally perceive as a stream of light particles, which are also known as photons that strike the retina of ours and allows us to see the events as they take place. Sure sounds lot like a fantasy that authors and espionage personas dream of but physicists from the ICL have proved that it could work in theory. This theory of space-time cloak, details of which have been published in the 16 November issue of the Journal of Optics, is believed to be an upgraded version of the "invisibility cloak" that was first proposed by Sir John Pendry, a theoretical physicist of the same ICL, back in 2006. And that study involved metamaterials. What is metamaterials? Put simply, metamaterials are a new class of materials which can be artificially engineered to distort light or sound waves. With conventional materials, light travels along a straight line but with metamaterials, it is possible to exploit a wealth of additional flexibilities to create undetectable blind spots. By deflecting certain parts of the electromagnetic spectrum, an image, thus, can be altered or at-least made to look like it has disappeared and metamaterials with their complex internal structures channel light around objects like water flowing around a rock in a river. According to Prof. Martin McCall, team leader of the recent project and professor of theoretical optics of ICL, ""Light normally slows down as it enters a material, but it is theoretically possible to manipulate the light rays so that some parts speed up and others slow down". The fact is the space-time cloak theory involves the refractive index, which is the optical property that basically administers the speed of light within a material that is continually changed, pulling light rays apart in time. And according to scientists this is when light "opens up", and that is, the leading half of the light speeds up and arrives before an event while the trailing half that is made to tag behind arrives comparatively late. When the leading edge of a light wave hits the space-time cloak, the metamaterial is engineered to speed up the light but when the trailing edge hits, the light slows down and is delayed. And the study predicts that between these two parts of the light, there will be a temporal void, an empty space in which there will be no illumination of light for a brief period of time. During this particular gap an event or action can take place and then by reversing the speeds of light, the gap can be closed again before the light reaches the observer, making it look nothing has happened. Experts believe that such space-time cloak could open up temporary corridors through which energy, information and matter could be transported, fairly undetected. Prof. McCall explains, ""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!"
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