... Solar System . ... Planets . ... Batygin and Brown suggest the planetтАЩs existence through mathematical modelling and simulations with detailed analyses of other distant objects and their strange orbital features. ... This is not necessarily a new theory as for many years it was thought that a fifth gas planet could have been ejected from the early Solar System, 4. 5 billion years ago due to a gravitational encounter with Jupiter and Saturn, for example during the period described by the Nice Model...