Large Moons And Life

Physicists have held over the past few decades that Earth's large moon has played an important role in the development of life by stabilizing Earth's axial tilt, thus helping to maintain consistent climate regimes to which life could adapt. A new study, however, suggests that while the Moon has indeed played that role, life-- even intelligent life-- could probably have arisen without the gravitational influence of a large moon.

According to the study, data argues that the gravitational influence of the other planets, but especially that of mighty Jupiter, would have kept Earth's axial tilt relatively stable even absent the Moon.

If this new view is correct, it has profound implications for the likelihood of extraterrestrial civilizations. Under the big moon theory, perhaps only one percent of all Earth-like worlds within the habitable zone of its parent star would have a large moon. Therefore, ET civilizations would be rare. But if planets in a solar system-- especially a Jupiter-sized planet-- could stabilize the climate on an Earth-like world, perhaps 75 percent of those worlds could be potential homes of civilizations.