Invisibility? I want it! Is it time to buy? Rising sales, declining listings.
by Tim Broadway
It is one thing to make an object invisible, like boy wizard 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 theft that takes place before your eyes and surveillance cameras. You do not 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 is 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 is a continuous flow of light. In their research, however, scientists were able to interrupt that flow for just an instant.
Another way to think of it is as if scientists edited or erased a split second of history. It is as if you are watching a movie with a scene inserted that you do not see or notice. It is there in the movie, but it is 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.
Using fibre optics, the hole in time is created as light moves along inside a fibre 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 fibres on a long table and almost looks like a pile of spaghetti, Mr. Fridman said.
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.
“It is significant because it opens up a whole new realm to ideas involving invisibility,” Dr. McCall said.
Researchers at Duke University and in Germany’s Karlsruhe Institute of Technology have made progress on making an object appear invisible spatially. Between those two approaches, the idea of invisibility will work its way into useful technology, predicts Dr. McCall, who was not part of either team.
The science is legitimate, but it is 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,” Mr. Kaku wrote in an e-mail, referring to the fictional boarding school Harry Potter attended. “The next step therefore will be to increase this time interval, perhaps to a millionth of a second.
Sales rose in 16 of the 28 markets the board tracks for its metro resale index, with seven of those markets posing a gain of more than five per cent over October’s number. Year-over-year sales rose in 15 areas, down from October, when 20 of the urban areas posted sales growth over 2010.
“The supply of new listings fell in 23 of 28 markets in November, but still exceeded year-earlier levels in 20 jurisdictions,” the board said. “An easing in supply of listings, combined with slightly weaker sales gains, lifted the sales-to-listings ratio in November in 23 markets. This left four areas as ‘sellers’ markets, while 21 remain ‘balanced’.”
The drop in listings resulted in higher prices in 17 areas month-over-month, while the year-over-year price was higher in 19 — with 16 markets recording growth of four per cent or more.
The Conference Board predicts all but three of the 28 markets it tracks for the index will see some increase in housing prices in the short term — the Ontario cities of Oshawa, London and Windsor being the exceptions.
Saskatoon and several Quebec markets — Gatineau, Montreal, Quebec, Sherbrooke, Trois-Rivieres and Saguenay — are expected to see the biggest increases in housing prices in the near term, the board said, predicting a seven per cent year-over-year gain.
A five per cent gain appears to be in the cards for Victoria, Vancouver, B.C.’s Fraser Valley, Calgary, Edmonton, Regina, Winnipeg, Halifax and Newfoundland, the board said. It expects housing prices to rise three per cent in Saint John, as well as the Ontario centres of Thunder Bay, Sudbury, Toronto, Hamilton, St. Catharines, Kitchener, Kingston and Ottawa.