Don't understand? Just gaze at the graphic above, provided by Cornell University. Ha ha, just kidding, I have no clue what that graphic means. To be honest, I'm not quite sure I understand the "time cloak" either (the AP explains it about six different ways), but what I do understand sounds awesome:
Another way to think of it is as if scientists edited or erased a split second of history. It's as if you are watching a movie with a scene inserted that you don't see or notice. It's there in the movie, but it's not something you saw, said study co-author Moti Fridman, a physics researcher at Cornell.
The scientists created a lens of not just light, but time. Their method splits light, speeding up one part of light and slowing down another. It creates a gap and that gap is where an event is masked.
This is all happening in beams of light that move too fast for the human eye to see. Using fiber optics, the hole in time is created as light moves along inside a fiber much thinner than a human hair. The scientists shoot the beam of light out, and then with other beams, they create a time lens that splits the light into two different speed beams that create the effect of invisibility by being too fast or too slow. The whole work is a mess of fibers on a long table and almost looks like a pile of spaghetti, Fridman said.
So: the caveat. Apparently the longest amount of time the research team thinks it can render things invisible is one one-thousandth of a second, and in order to make the "time cloak" last an entire second, we'd have to build a machine "about 18,600 miles long." Back to your science castles, scientists! Make me a time cloak!