The cycles are, however, observed. They do fall out from the Kepler and Newton equations for orbital motion- they are not mysteries.
The periodicity of the cycles does correlate rather well with glaciation cycles over the last 700 ky, but not perfectly. It seems odd that insolation changes brought about by observed orbital elements would NOT influence climate.
There's lots of stuff written on the topic, much of it online now.
http://en.wikipedia.org/wiki/Milankovitch_cycles
They are mysterious. If there were some theory that explained causes this might be related to science. The original comment was that earth's orbit expands and contracts and that causes an ice age in my attitude. Precession of the nodes is not at all what is being discussed here.