As a reminder, the reason for the seasons is the tilt of the planet. As our world goes from having the north pole pointed toward the Sun to having the south pole tilted more toward the Sun, we see the temperatures and weather in Earth’s hemispheres vary back and forth. This causes animals to migrate and hibernate, and it creates growing seasons. In many ways, the complexity of our planet is driven by the desire for life to spread and multiply, and the need for that life to adapt to the environments it is spreading into.
In a presentation at the Goldschmidt Conference, researchers lead by Stephanie Olson postulate that planets with a tilt like Earth’s will develop more complex life than planets that are upright and never experience seasons.
According to Olson: There are several factors to consider in looking for life on another planet. The planet needs to be [at] the right distance from its star to allow liquid water and have the chemical ingredients for the origin of life. But not all oceans will be great hosts for life as we know it, and an even smaller subset will have suitable habitats for life to progress towards animal-grade complexity. Small tilts or extreme seasonality on planets with Uranus-like tilts may limit the proliferation of life, but [a] modest tilt of a planet on its axis may increase the likelihood that it develops oxygenated atmospheres that could serve as beacons of microbial life and fuel the metabolisms of large organisms. The bottom line is that worlds that are modestly tilted on their axes may be more likely to evolve complex life. This helps us narrow the search for complex, perhaps even intelligent life in the Universe.
While we can’t yet determine if distant exoplanets are tilted, this research definitely adds an interesting dimension to the way we think about life.