Rolling luggage is both a blessing and a curse for hurried travelers. While we no longer need gym-toned biceps to heft our sundries through the airport, the slightest misstep can send a two-wheeled suitcase rocking and spinning into an uncontrollable disaster. Now, scientists think they know why rolling suitcases are so annoyingly unsteady at exactly the wrong times.
French researchers, writing in the Proceedings of the Royal Society A, say that the problem comes down to simple physics. A