We identify various structures on the configuration space C of a flying saucer, moving in a three-dimensional smooth manifold M . Always C is a five-dimensional contact manifold. If M… Click to show full abstract
We identify various structures on the configuration space C of a flying saucer, moving in a three-dimensional smooth manifold M . Always C is a five-dimensional contact manifold. If M has a projective structure, then C is its twistor space and is equipped with an almost contact Legendrean structure. Instead, if M has a conformal structure, then the saucer moves according to a CR structure on C . With yet another structure on M , the contact distribution in C is equipped with a cone over a twisted cubic. This defines a certain type of Cartan geometry on C (more specifically, a type of ‘parabolic geometry’) and we provide examples when this geometry is ‘flat,’ meaning that its symmetries comprise the split form of the exceptional Lie algebra $${\mathfrak {g}}_2$$ g 2 .
               
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