While 11826 was steadily moving away from the suns gravity well, towards Proxima Centauri, 11825 was discovered to have been in orbit around the sun for approximately 300 million years. There was wide speculation among the people who had access as to whether or not it wiped out the dinosaurs with a close pass. Indeed, it did.
It is now known that the exact same thing is going to happen in 2012, as displayed in the simulation. It takes approximately 125 to 250 million years for the planetary orbits to repair themselves due to the gravitational riptides from Rigil Kentaurus.