Earlier this week, the Templeton Foundation announced the 2009 winner of its $1.4 million Templeton Prize, French physicist and philosopher Bernard d’Espagnat. He is best known for his work to understand and test one of the strangest predictions of the theory of quantum mechanics: that particles are uncannily good players of The Newlywed Game. Pairs of them can give exactly the same responses to measurements conducted on them at the same time in isolated booths.

In the 1960s, physicist John Stewart Bell derived a set of mathematical inequalities that the responses would obey if the particles had some kind of a built-in cheat sheet. But d’Espagnat, Alain Aspect, and other experimenters found that particles violate these inequalities. Somehow the particles retain an intimate connection that transcends space. Physicists, even the most romantically inclined among them, have yet to fathom it.

Of all the puzzling physical effects predicted and explained by quantum mechanics, one of the most counterintuitive is that fluctuations in a vacuum can exert forces on objects—almost as if those objects are getting something from nothing. Even in empty space, there are flutterings of energy, and sometimes those tiny ripples act in demonstrable ways. One example is known as the Casimir effect, predicted to exist in 1948 by the late Dutch physicist Hendrik Casimir, in which quantum fluctuations create an attractive force between two surfaces in a vacuum.

A group of researchers report in the online edition of Nature that they demonstrated for the first time the repulsive version of this quantum effect. Their results show that by judiciously choosing two materials (silica and gold) immersed in a fluid (bromobenzene), quantum fluctuations can be seen to drive the materials apart. This repulsive version of the Casimir effect had long been predicted but never observed.

Once upon a time, physicists raised eyebrows when they said we existed in multiple universes. But this "many worlds" theory has become widely accepted since it was first proposed in 1957 by eccentric physicist Hugh Everett.

Everett, who died in 1982 at the age of 51, is the subject of a new documentary, Parallel Worlds, Parallel Lives, which airs today at 8 P.M. Eastern time on PBS. Journalist Peter Byrne, whose 2007 profile of Everett in Scientific American explains the theory and describes Everett's troubled private and professional life, appears in the film.

"If everything physically possible happens in the universe, why do we only see one possibility at a time? That's the question philosophers are beating their heads bloody trying to answer," Byrne tells us.  "Everett's answer is there's more than one you, and you are splitting into trillions of copies of yourself every time there's a quantum interaction of a certain size."

No matter how many times researchers try, there's just no getting around the weirdness of quantum mechanics.

In the latest attempt, researchers at the University of Geneva in Switzerland tried to determine whether entanglement—the fact that measuring a property of one particle instantly determines the property of another—is actually transmitted by some wave-like signal that's fast but not infinitely fast.

Their test involved a series of measurements on pairs of entangled photons (particles of light) that were generated in Geneva (satellite view at left) and then split apart by optical fiber to two villages 18 kilometers (11 miles) apart where the team had set up photon detectors. (In 2007, researchers transmitted entangled light 144 kilometers between two of the Canary Islands.)