Lasers. Is there anything they can't do? The latest addition to the 50-year-old technology's bag of tricks comes courtesy of a team of researchers from the Australian National University, who've managed to create a laser beam that effectively functions as a tiny tractor beam. The key, it seems, is that the laser beam is hollow, which allows tiny particles to be trapped in what the researchers describe as a "dark core," which in turn causes the particles to be pushed along the beam by an effect known as the "photophoretic force." As you might expect, that only works on very tiny partic
