Earth's Guardian

Bill Whittle has an interesting segment at PJTV.com talking about why the earth may be alone in the universe as a life-supporting planet despite the fact that there are probably millions of similar planets out there and it's the moon. That I wasn't expecting. 

He reports that the moon was formed in a gigantic collision with another similar-sized planet early on and the debris that flew off was captured by earth's gravitational pull and coalesced into the moon. Since then it has done two important things.

First, it is a shield. As Whittle notes, if you look at all the craters on the moon you must realize that all of those would have hit earth but for our celestial guardian and developing life in a constant artillery barrage is not easy to do. A second shield function is that the moon has enough of its own gravitational field that it deflects the orbit of extinction-sized asteroids, comets, etc. and most often causes a near-miss with earth.

The second function performed by the moon is that exerts just enough gravitational pull on the earth to keep the earth's axis canted at exactly the right angle to produce seasons and tides, both of which refresh life on earth on a seasonal basis. 

Bill chalks all this up to an astounding occurrence of chance. Sounds to me as if it's almost like someone planned it. Hmm...