So far, the theories of the origin of the moon are inadequate. There is no general agreement on any This paper brings to light a simple outstanding idea. The sun and the moon were once binary stars. Mass transfer occurred with the present sun gaining mass from the other star. Actually, the entire envelope of the other star was transferred to the present sun leaving the core of this companion. It is this core that cooled off and ended up as our moon. The face of the moon was cooled off abruptly while the back of the moon cooled gradually. This made the back of the moon almost free from Marias. We have to invoke another very important concept. The earth was created as an orphan planet. The binary suns system captured the earth as a circumbinary planet. Following mass transfer, the hot moon was captured by the earth and was locked in such a way that its near side always faced the earth. With both of the sun and the shinning hot moon, the earth experienced no night. The near side the moon was cooled off suddenly. This allowed night to occur on the earth. The far side of the moon cooled gradually and that made the observed discrepancy between the two faces of the moon. The very existence of He-3 on lunar surface, which is the product of fusion reactions inside the core of stars, is a clear-cut evidence that the moon is actually the core of a star. In addition, gamma ray photos of the moon show excessive illumination. This gamma ray is actually emanating from inside the moon as a byproduct of fusion reaction accompanying, He-3 production. An easy task to prove. In conclusion, When Armstrong stepped on the moon, he did not realize then that he actually walked on the cooled core of an ex star.