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Researchers Say They've Been Able To 'Cloak' Time

"Harry Potter" is able to hide himself. Cornell researchers say they've been able to hide time. i i

"Harry Potter" is able to hide himself. Cornell researchers say they've been able to hide time. Jaap Buitendijk/for Warner Bros. hide caption

itoggle caption Jaap Buitendijk/for Warner Bros.
"Harry Potter" is able to hide himself. Cornell researchers say they've been able to hide time.

"Harry Potter" is able to hide himself. Cornell researchers say they've been able to hide time.

Jaap Buitendijk/for Warner Bros.

This news has a little bit of a Harry Potter feel to it. A touch of Back to the Future. Maybe some Doctor Who too.

Researchers at Cornell University, as MIT's Technology Review reports, "have designed and built a cloak that hides events in time."

Now by cloak, they don't mean a piece of magical cloth like Harry's. No, the Cornell scientists (Moti Fridman, Alessandro Farsi, Yoshitomo Okawachi, and Alexander L. Gaeta) write that "to create our temporal cloaking system, we implement a split time-lens (STL) composed of two half time-lenses ... connected at the tips."

Gizmodo explains it this way:

"The time cloak takes two of those lenses and arranges them so that one compresses a beam of light while the other decompresses it. That leaves the beam seemingly unchanged, but the diffraction and dispersion actually 'cloak' small events in the beam's timeline."

How small of an "event" have they been able to cloak so far? "Right now, the cloak can only last for 120 nanoseconds, and the theoretical max for the current design measures just microseconds," Gizmodo says. One microsecond equals one millionth of a second.

It's a start.

Update at 2:55 p.m. ET, July 19: For all those looking for more of an explanation (or perhaps a better one?), there's now a post by Adam Frank over at the 13.7 blog.

Of cloaking experiments, he writes that they:

"Rely on the complex realization of a simple truth about our experience of the world. We have no 'direct' knowledge of the world-in-of-itself but, instead, are forced to rely on signals carried to us from external objects. If the properties of the signals are somehow changed while they are traveling to us then our experience of the world is changed as well."

See his post for more.

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