Unique Properties of the Earth-Moon System
- The Earth-Moon system exists because of a rare set of circumstances
- A large object impacted the Earth from just the right
direction and at just the right speed
late in the process of the formation of the Solar System.
- Other planets (with the exception of Pluto) tend to have tiny satellites. The Moon is exceptional.
- Maybe fewer than 1 in 100 other "Earth's" have a Moon like ours.
- Could these special circumstances have unique implications for
the origin and evolution of complex life on Earth?..
or is it simply a coincidence that complex life exists on a planet with such a unique moon?
- The event grossly altered the surface chemistry of the
- Was this a factor in enabling life to arise?
- Was it a setback for life that had already gotten
- The existence of such a large Moon nearby continues to
influence our planet.
- Tides are substantially higher (especially so early in
Earth history when the Moon was much closer).
- Tidal boundaries and tide pools are thought
to be especially important in driving evolution and
the emergence of life on land.
- The Moon stabilizes the Earth's tilt in a small
- Without the Moon the Earth's tilt would vary substantially
over time due to the small gravitational influence of the
- At times the Earth could be tipped on
its side relative to the Sun giving months of darkness
or daylight at a time significantly varying the climate!