Actually I've heard of the Red Dwarf second sun theory too. Because most stars in the universe have twins (binary star systems). It is theorized that because at a relatively regular interval, our planet has a mass extinction event of some sort, that our Sun's twin has an orbit that goes right through the asteroid belt outside our solar system, and when it does, it basically kicks up those rocks and sends some of them into our system, which in turn collide with planets.
Of course, there is no hard proof behind it, but it is an interesting theory
