There is no mystery.
 
Gen 1:14  And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years:
Gen 1:15  And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so.
Gen 1:16  And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also.
Gen 1:17  And God set them in the firmament of the heaven to give light upon the earth,
Gen 1:18  And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good.
 
 

CAC:
"mystery of how the Moon formed"
 
God Bless, John T.