Scientists figure out how to "cloak" time
In this illustration, provided by Cornell University, scientists demonstrate how they have have created, a new invisibility technique that doesn't just cloak an object - like in Harry Potter books and movies - but masks an entire event. It is a time masker that works by briefly bending the speed of light around an event. / Associated Press
WASHINGTON - It's one thing to make an object invisible, like Harry Potter's mythical cloak. But scientists have made an entire event impossible to see. They have invented a time masker.
Think of it as an art heist that takes place before your eyes and surveillance cameras. You don't see the thief strolling into the museum, taking the painting down or walking away, but he did. It's not just that the thief is invisible - his whole activity is.
What scientists at Cornell University did was on a much smaller scale, both in terms of events and time. It happened so quickly that it's not even a blink of an eye. Their time cloak lasts an incredibly tiny fraction of a fraction of a second. They hid an event for 40 trillionths of a second, according to a study appearing in Thursday's edition of the journal Nature. We see events happening as light from them reaches our eyes. Usually it's a continuous flow of light. In the new research, however, scientists were able to interrupt that flow for just an instant.
Other newly created invisibility cloaks fashioned by scientists move the light beams away in the traditional three dimensions. The Cornell team alters not where the light flows but how fast it moves, changing in the dimension of time, not space. They tinkered with the speed of beams of light in a way that would make it appear to surveillance cameras or laser security beams that an event, such as an art heist, isn't happening.
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.
Time hole
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.
"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."
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.
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It is the first time that scientists have been able to mask an
event in time, a concept only first theorized by Martin McCall, a
professor of theoretical optics at Imperial College in London.
Gaeta, Fridman and others at Cornell, who had already been working
on time lenses, decided to see if they could do what McCall
envisioned.
It only took a few months, a blink of an eye in scientific research time.
New direction in science
"It is significant because it opens up a whole new realm to ideas involving invisibility," McCall said.
Researchers at Duke University and in Germany's Karlsruhe Institute of Technology have made progress on making an object appear invisible spatially. The earlier invisibility cloak work bent light around an object in three dimensions.
Between those two approaches, the idea of invisibility will work its way into useful technology, predicts McCall, who wasn't part of either team.
The science is legitimate, but it's still only a fraction of a second, added City College of New York physicist Michio Kaku, who specializes in the physics of science fiction.
"That's not enough time to wander around Hogwarts," Kaku wrote in an email. "The next step therefore will be to increase this time interval, perhaps to a millionth of a second. So we see that there's a long way to go before we have true invisibility as seen in science fiction."
Gaeta said he thinks he can get make the cloak last a millionth of a second or maybe even a thousandth of a second. But McCall said the mathematics dictate that it would take too big a machine - about 18,600 miles long - to make the cloak last a full second. "You have to start somewhere and this is a proof of concept," Gaeta said.
Still, there are practical applications, Gaeta and Fridman said. This is a way of adding a packet of information to high-speed data unseen without interrupting the flow of information. But that may not be a good thing if used for computer viruses, Fridman conceded. There may be good uses of this technology, Gaeta said, but "for some reason people are more interested in the more illicit applications."
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The method as described is little more than comb filtering, projecting a altered-phase beam of light back onto itself, where the waves meet at exactly opposite phase, cancellation happens, because a number plus it's negative equals zero.
While the zero effect can cause light's cancelled frequencies to be invisible, that has nothing to do with time.
There is only one way to alter the "tempo" of time by any measurable degree, which is, of course with giant masses frame-dragging time-space, and the effect can only be seen from observation from outside the area so altered.
Particles are fine for experimentation, but then use waves for applications.
rightwing-nuts have somehow discarded pre-Obama..time has started when he took office...
don't believe me? just ask a teabagger..
So really...which came first ? The chicken or the egg ?
*-----------
The chicken - God invented the chicken, THEN the chicken laid an egg! : )
Just as turkeys and vultures came from T-rex eggs.
Now, here's some food for thought. You sit down to read a book and say it's 1:00 in the afternoon. You finish the book and it's 6:00 but it seems to you like you've only been sitting there for maybe an hour. On the other hand, you go listen to someone at work ramble on about the proper way to fill out a form or something like that that doesn't occupy your mind and time comes to a halt. Now there's a noticeable change in time relative to brain activity. If the brain is engaged and occupied, time flies by but only minutes seem to go by, but if the mind is not engaged, time comes to a halt and drags on forever.
The speed of light is constant in a vacuum and in a constant gravitaional field. When light passes through another material, like glass, the light slows down and changes direction (defraction). Also, when light passes by an intense gravitaional field (black hole) it slows and changes direction (gravitational lensing).