The Moon is important and unique for many reasons. The Moon is huge for one. Proportional to the
Earth, the Moon is far larger than any other
satellite in the
Solar System, with the exception of
Pluto's moon
Charon, but Pluto isn't much of a
planet. This means that the Earth gets
phenomenon like tides and visible
phases of the moon. If the moon had proportionally the size of say,
Mars' moons, then we would see neither of these, and they are both important.
The tides the Moon created may have played a role in getting life to move out of the oceans, since some animals would be trapped in the intertidal zone and adapted to being out of water for a period of time.
The Moon has played a very important role in the development of astronomy, which is the oldest science known to man because the first astronomical observations were the phases of the Moon which have occurred for all of recorded history. The Moon is the basis for many calendars, including ours.
It's also thought that the relationship between the Moon's phases and the
menstrual cycle resulted in many
primitive cultures being
matriarchal. Most importantly, we've been to the Moon. It's the only other
celestial body that human beings have set
foot on. Next time you go outside at night, look up and think about how amazing it is that we put a
man on the Moon.