MOON-EARTH WOBBLE STABOLIZER from the www.StarDate.org website 6-30-07)
This is a brief outline of the history of essential role of Earth's Moon and its special role stabolizing Earth's wobble and making biodiversity possible on Earth because of the predictable seasons caused by the stabolizing gravitational pull of the Moon during Earth's annual orbit around the star we call "our Sun."
Earth's partner in its yearly orbit around the Sun, the Moon, is geologically dead. Dried lava fields called "maria" (Latin for "seas") cover its surface, along with impact craters. The maria formed about four billion years ago, when giant asteroids punched holes in the Moon's crust, allowing molten rock to bubble to the surface, where it cooled and hardened.
The Earth and the Moon are more like a double planet than a planet and a moon. The Moon is quite large in comparison to Earth. It is about one-quarter of Earth's diameter. The two gravitationally interact with each other, causing Earth's regular ocean tides.
Also the unique Earth-Moon interaction has other important consequences. Over billions of years, the Moon's rotation has become "tidally locked," so that the same side of the Moon always faces our Earth. And the Moon acts to stabilize a "wobble" in Earth's axis. Over billions of years, this has led to a much more stable climate, which has been essential to the evolution of life. The Earth-Moon interaction also slows Earth's rotation by about two milliseconds per day per century.
The origin of the Moon was probably a "big whack," which is the theory that was developed after scientists analyzed the rocks brought back to Earth by Apollo astronauts and Soviet Luna probes, as well as used the readings of seismometers left on the lunar surface by the astronauts to record "moonquakes."
Their studies showed that the Moon's composition closely resembles the Earth's own crust and mantle. From this, scientists have concluded that a Mars-sized body hit Earth within a few million years of its formation. The impact vaporized much of the chemical material in Earth's crust and mantle and blasted them into space, forming a ring around the planet. This material quickly coalesced to form the Moon.
In summary, the Moon has been Earth's steady companion for billions of Earth year's in its essential role as the stabolizer of Earth's wobbling position in the sky as it perpetually travels around the Sun in our unique solar system, making the biodiversity of life on Earth possible because of the predictable annual seasons.
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