Scientists have proven in a very small experiment that it's possible to create a 'temporal cloak' that can make you invisible by opening a gap between light waves. The science is pretty wild, but it actually works.
We're already a little bit familiar with the principle of using metamaterials to make something invisible to light: a metamaterial cloak can bend light all the way around whatever's inside it, creating a space that's effectively invisible.
A different way of making something invisible is to slow light down and then speed it up again. Controlling the speed of light is actually pretty simple: the denser something is, the slower light moves through it. By using an optical fiber that changes density when shot with a laser, scientists were able to speed up the front of a light pulse while slowing down the back enough to open a small gap, which they could then seal by speeding the light waves up again.
It's this gap that's the temporal cloak. Anything inside is not only invisible to an observer, but time that passes normally inside the gap will pass instantaneously to anyone watching from the outside, since the gap is sealed before light waves reach the observer. So if you activate your temporal cloak, you wouldn't actually disappear: instead, you'd create a time gap in which you could do absolutely anything while remaining undetectable. Someone watching you would simply see you as you were before the cloak was activated, and then if you moved around and shut it off, the observer would see you teleport instantly from one place to another.
Not to crush all your evil plans or anything, but so far, this effect has only been used to create a five-nanosecond gap in an optical fiber, which is probably not enough time for you to do anything cool with, even if you could somehow manage to stuff yourself into an optical fiber, which you can't. The researchers, though, are pretty excited, and envision a future in which a spacetime cloak will allow them to steal stuff without being detected by security cameras. Seriously.
A Spacetime Cloak, Or History Editor (PDF, requires free login), via io9
Image via I Am Hilarious
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