Researchers using sophisticated computer models suggest a giant exo-solar planet may be quite the swinger:
(MSNBC) — The giant exoplanet, known as 55 Cancri d, gets tugged by a faraway companion star as it orbits its own parent star. As a result, the planet performs a flip over the course of millions of years, and the other four planets in the system follow suit, researchers said.
The mechanism is novel, but we may not need to look so far away for planets with variable obliquity. Earth seems to be locked into a narrow range, thanks to the moon we tend to maintain an axial tilt between 24 and 22 degrees. But the axis of planets with some room between themselves and the influential sun, like Mars, could also vary greatly. If so it would have profound consequences on the climate and meteorology for the Red Planet or any other. We would tend to think of such worlds as uninhabitable because of the extremes, but if complex life ever evolved in such a place, it would probably find the swings just right.