After several contestants in the 2013 world swimming championships in Barcelona, Spain, remarked that the racers in lanes 5 to 8 seemed to swim faster than those in lanes 1 to 4, two researchers investigated further and concluded, in July, that there was a rogue current on the lane-8 side of the pool. In fact, most of the losers swam in lane 1, and the lane 8 swimmers produced a glut of medals, and, wrote the researchers, a current would be “the only cause that we can propose to explain these findings.”