Notwithstanding problems of scale it can be a useful tool in teaching children the relative positions of the planets. Orreries are also very beautiful. Brian Greig, in Victoria, Australia, recreates historical orreries and other scientific instruments and accepts commissions to make bespoke models. His site can be seen here.Until the 16th century the unquestioned commonly and religiously held belief was that the earth was the centre of the universe and the sun, planets and stars revolved around it. Heaven was a fixed place and perfect. Any other opinion was considered to be heresy.