> Moon as a necessary ingredient to sustain the Earth's magnetic field.

I know that idea has been around a long while; the most recent place I recall it was the book "Rare Earth" but I'm sure I read it back when printed paper was the hot new way of distributing ideas.

I recall reading decades ago about an experiment raising animals in magnetically shielded boxes finding that absence of Earth's field had bad effects on their health. That may have been 1950s science fiction magazine stuff, my memory's not helping me cite the source.