Could dark energy find a hidden world in our solar system? The Dark Energy Survey is a Southern Hemisphere observation project designed to probe the acceleration of the universe, by looking at the most distant galaxies. But since it started peering into to the sky three years ago, the project has proved surprisingly useful for answering mysteries much closer to home. The evidence for a ninth planet in our solar system might be hiding in data gathered as part of the survey, and if so it could be found by the end of summer, an expert told MailOnline. In January, Caltech astronomers Professor Konstantin Batygin and Professor Mike Brown predicted the existence of what they, somewhat controversially, termed 'Planet Nine'. They used mathematical modelling and computer simulations to find the planet would exactly explain a strange clumping behaviour of a group of dwarf planets in the Kuiper Belt, a field of icy objects and debris beyond Neptune. The unknown world, dubbed 'Planet X' by others,