• Moon was a part of the earth which has been detached. Indications reject that.
• Moon was formed indepedently from the same cloud of dust and gass that created earth. From the minute of her creation Moon became satelite of earth. Russian scientists not only deny this theory, not only because of the different thickness of the two planets, but also because the different chemical analysis  of the samples that proved that Moon "doesn't have the same material chemical constitution like earth".
• Moon came from another world, (maybe from a different sun system) and became satellite of earth. That's the famous theory of "attraction" that supposes that Moon was wandering in our sun system until, under some special coincidences, she was captured from the earth gravity and became a satelite. Russian scientists doubt about this theory since it's impossible a planet like Moon to became a satelite under "normal conditions" in such a small planet, like earth.

    Vazin and Sterbakof conclude at:
    "In reality, scientists that study fuctions of the universe, although they propose great solutions for other astronomical problems, they cannot explain the forming of the double system Moon-Earth.
    So they give their explanation:
    "Moon is an artificial satelite of Earth, which came to that position after sensitive handlings of logical creatures, completely unknown to us".