Magic carpets a reality, says professor

Fictional flying carpets are ubiquitous and have appeared in literature since ancient times. Now they have caught the attention of a leading mathematician. Although he has only succeeded in showing that flying is practical for a bank note sized carpet, Prof Lakshminarayanan Mahadevan of Harvard University in Cambridge, Massachusetts, and his co-workers believe that one capable of ferrying a person is far from being a pantomime fantasy. His claims, published in the journal Physical Review Letters, come just in time for productions of Aladdin and arise from working out the aerodynamics of a flexible, rippling sheet moving through a fluid, such as air. The conclusion is that it should be possible to make one that will stay aloft. In earlier work, Prof Mahadevan showed how how sheets become wrinkled and cans crumple. Now, with colleagues in New York and Valbonne, France, he has turned his attention to a more uplifting feat that could grace the pages of the Arabian Nights (One Thousand and One Nights). The key to levitating a carpet is to create uplift by making ripples that push against air close to a horizontal surface, such as a floor. The undulating movements create a high pressure in the gap between the carpet and the floor, "roughly balancing its weight." The magical part comes from the discovery that, as well as lifting it, the ripples can drive the carpet forward - a handy trick for a panto - because they make the carpet tilt slightly, moving towards the raised edge. Prof Mahadevan tells The Telegraph that this would make the carpet move around like some marine creatures: "Submarine rays and skates use more complex movements to skim over the ocean floor - but the idea is the same." To stay afloat in air, a sheet measuring about four inches long and 0.1 millimetres thick would need to vibrate at about ten times per second with an amplitude of about 0.25 millimetres, he estimates.