Due to the physical difficulties in directly measuring the size of a distant star, the identity of the largest star is a matter for debate amongst astronomers. The current most likely candidate is VY Canis Majoris, a red supergiant some 5,000 light years away. Estimates of its size give it a diameter of between 2.5 and 3 billion km (1.55 and 1.86 billion miles), or 1,800 – 2,100 times that of the Sun. If placed at the centre of the Solar System, its outer surface would reach beyond the orbit of Jupiter.