If I recall correctly it was never stated for certain. They seem to use that term loosely as non-restrictive amount of time which helps writers escape worldbulding problems. It's kinda the same as lots of stuff happened long long ago I mean 1000 years ago which I don't believe could refer to literally 1000 years.



Also moon in real life usually means month. In some languages like Czech the word for month and moon is the same.