Our moon is slowly escaping the earths gravity, at about 3.8 cm every year. Currently the moon is about 4.527 0.01 billion years old, but hasn't always been as far away or as slow in revolution.
As far as the question of how it got there, when the impact of Theia (or sometimes called Orpheus) ejected large amounts of the earths crust off, the materials were either close enough to be recaptured by the earths gravity or too far away. Of the materials too far away to be recaptured, the materials that had a high enough velocity, were carried away, the mass that remained in that band that wasn't far enough away or close enough, eventually was pulled together by gravity to form the moon. So the question you ask is misleading, the moon wasn't 'put' into orbit, it was 'built' in orbit.
Mars for example has two 'moons' that are captured asteroids, Phobos and Deimos. Mars has a weaker gravity though owing to its smaller mass.
A really good information source with computer simulations to help you understand the process,
http://www.psrd.hawaii.edu/Dec98/OriginEarthMoon.html
or
http://www.xtec.es/recursos/astronom/moon/camerone.htm
-x
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"Debate is an art form. It is about the winning of arguments. It is not about the discovery of truth. There are certain rules and procedures to debate that really have nothing to do with establishing fact ” which creationists have mastered. Some of those rules are: never say anything positive about your own position because it can be attacked, but chip away at what appear to be the weaknesses in your opponent's position. They are good at that. I don't think I could beat the creationists at debate. I can tie them. But in courtrooms they are terrible, because in courtrooms you cannot give speeches. In a courtroom you have to answer direct questions about the positive status of your belief. We destroyed them in Arkansas. On the second day of the two-week trial we had our victory party!"
-Stephen Jay Gould
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