The moon manages the tilt of earth, in its rotation and hence the weather on our planet.
See an hour long BBC video by clicking here
Additional Reading
The Unreasonable Effectiveness of Mathematics in the Natural Sciences
What do we really need the Moon for?
What about Mullah Nasruddin’s point of view? He said that the moon is much more important as it gives us light in the night when it is dark. The day is light anyway.