Scientists say they have cracked a nearly eight-decade-old riddle involving the Möbius strip, a mathematical phenomenon that has also become an icon of art.
Popularised by the Dutch artist MC Escher, a Möbius strip entails taking a strip of paper or some other flexible material. Take one end of the strip, twist it 180 degrees, and then tape it to the other end. This creates a loop that has an intriguing quality, dazzlingly exploited by Escher, in that it only has one side.
Since 1930, the Möbius strip has been a classic poser for experts in mechanics. The teaser is to resolve the strip algebraically — to explain its unusual shape in the form of an equation.
In a study published on Sunday that lyrically praises the strip for its ”mathematical beauty”, two experts in non-linear dynamics, Gert van der Heijden and Eugene Starostin of University College London, present the solution.
What determines the strip’s shape is its differing areas of ”energy density”, they say.
”Energy density” means the stored, elastic energy that is contained in the strip as a result of the folding. Places where the strip is most bent have the highest energy density; conversely, places that are flat and unstressed by a fold have the least energy density.
If the width of the strip increases in proportion to its length, the zones of energy density also shift, which in term alters the shape, according to their equations.
A wider strip, for instance, leads to nearly flat, ”triangular” regions in the strip, a phenomenon that also happens when paper is crumpled.
The research may seem esoteric, but Van der Heijden and Starostin believe it also has practical applications. It could help predict points of tearing in fabrics and be useful for pharmaceutical engineers who model the structure of new drugs.
The Möbius strip was named after a German mathematician, August Ferdinand Möbius, who discovered it in 1858. Another German, Johann Benedict Listing, separately discovered it in the same year. — Sapa-AFP