The origin of the Moon and its role for life on Earth has become a topic of deep discussion, beginning in the 1970s when Apollo astronauts brought back lunar rock, which showed that the Moon was once part of the Earth.
In this talk, I will discuss past and recent theories about the origin of the Moon and also the orbital evolution of the Moon from its formation to the present epoch. The Moon was closer to Earth in the past, which had significant effects for the evolution of complex life on Earth (e.g. higher tides, stronger winds). In a “Gedankenexperiment”, I ask the question "What if the Moon did not exist?" How would complex life on Earth have evolved and been sustained and protected over geological times if the Moon had not formed? No other planet in our solar system has a comparable companion, particularly Venus, an Earth twin by mass, has none. I will consider these issues and speculate on others, such as whether the Moon may play a role in Earth's plate tectonics and in the generation of Earth's geodynamo (magnetic field). These are critical conditions supporting the habitability of our oasis planet Earth.
