Participants said that they had fought hardest to hire real-life applicants with whom they had felt a deep connection, typically because of shared interests or personality traits.

Fischbach is the epitome of the curious soul, constantly poking around at the edges of known physics in search of something that other people overlooked: a fifth force of nature, for instance, or a flaw in Einstein’s theory of relativity. About a decade ago he noticed a juicy oddity buried in a pair of overlooked papers, one from Brookhaven National Laboratory, the other from a German measurement institute. The two teams were watching the decay of certain radioactive elements. This is a routine bookkeeping style of research: According to known physics, this type of radioactive decay is a fundamental process that unfolds at an unchanging rate, and all the researchers were aiming to do was to measure that rate and record it for reference. Instead, both teams got a rude surprise. The rate of decay in their samples was not steady but varied according to the season. That fluctuation was small, about 0.3 percent, but it was consistent and—Fischbach noted happily—very, very weird.

Most scientists dismissed the two papers as flukes and moved on. Fischbach decided to take the results at face value. “We had two experiments on two different continents seeing essentially the same thing,” he says. What effect, he wondered, could make a lump of radioactive silicon decay faster or slower?

In conjunction with his Purdue colleague Jere Jenkins, Fischbach realized that the seasonal nature of the variation might provide the crucial clue. Earth follows a slightly oval path around the sun, closest in January and farthest in July. The changes in radioactive decay rate tracked that pattern, rising and falling on cue over the course of the year. It seemed as if it affected the way atoms decayed on Earth, 93 million miles away.

Sensing they were onto something big, Fischbach and Jenkins scoured the literature and found more reports of radioactive decay enigmatically slowing down and speeding up, results so contrary to expectation that they, too, had largely been tossed into the dust bin of odd results and equipment error. Even more intriguing, these experiments also seemed to show a seasonal variation. The only way to determine if the effect was real, Fischbach decided, was to run an experiment of his own. So his group acquired a sample of radioactive manganese-54, which decays in just under a year, neither too slow nor too fast to study. Then they monitored the lump closely, and waited.

On December 12, 2006, the vigil paid off. That day, satellites in orbit around the Earth recorded a flare on the sun, which produced a spike of X-ray emissions. Also that day, Fischbach recalls, “when we looked at our data there was a sharp drop in the count rate [the rate of radioactive decay], exactly coincident with the flare.” Now he had an important additional piece of information: Proximity to the sun seemed to influence radioactivity, and violent activity on the sun could also increase or decrease decay rates.

A beam called a Bessel beam is at the heart of the demonstration. Bessel beams direct light in concentric circles around a single dot, and this gives the beams an interesting property: they reform after passing an obstacle. In mathematics, if not in real life, such beams could propagate forever, because they don’t suffer the diffraction that scatters ordinary lasers.

The way that Bessel beams reform behind a (small) obstruction has already made them useful for optical tweezers, but Ruffner and Grier found that a single beam couldn’t be sufficiently tuned to act as a tractor.

To create the “tractor beam”, the researchers added a second Bessel beam, and then varied the relative phase of the two beams. This makes the optical trap created in the beams move – and the trapped particle moves with the trap, “allowing bi-directional transport in three dimensions”, they write.

As New Scientist explains, the interaction of the two Bessel beams creates an alternating pattern of bright and dark regions. With the right tuning, photons in the bright regions scatter back towards the light source, creating a pico-scale light pressure that pushes a particle in the beam towards the next bright region.

The demonstration by Ruffner and Grier is not, however, ready to trap the Starship Enterprise: they demonstrated its effectiveness by moving microscopic spheres of silica, suspended in water, over distances of 30 micrometers. ®