Vincent Black Shadow Vincent Black Shadow Motorcycles produced by Vincent H·R·D at their factory in Stevenage, Hertfordshire, England were renowned for their design innovation, engineering excellence and high performance. Already advertising their existing 110 mph Rapide machine as ‘The world’s fastest production motorcycle’, in February 1948 the distinctive Vincent Black Shadow was announced with a top speed of 125 mph. Built in three different Series over the course of its life, the line continued until 1955, after which the company stopped all motorcycle production. The Black Shadow uses a version of the air-cooled four-stroke 50° V-twin engine that powers the Vincent Rapide. Bore
Nonsingular black hole models Nonsingular black hole models A nonsingular black hole model is a mathematical theory of black holes that avoids certain theoretical problems with the standard black hole model, including information loss and the unobservable nature of the black hole event horizon. For a black hole to physically exist as a solution to Einstein's equation, it must form an event horizon in finite time relative to outside observers. This requires an accurate theory of black hole formation, of which several have been proposed. In 2007, Shuan Nan Zhang of Tsinghua University proposed a model in which the event horizon of a potential