Kristen,
My talk about earth/heart/mind is more intuitive, than anything. I know little to nothing about the chakras, though I would like to. However, through taking a series of chi-kung classes, I have found there is a lot of discussion about staying grounded through focusing on the dantien and the soles of one's feet. There is also talk of the heart as an energy center, and the mind. The heart and the mind are where our energy tends to get trapped if we don't learn to focus and channel our energy into our dantiens, and down into the earth.
My feeling is that in our body, our lower bodies and dantien represent earth/grounding, our minds and mental energies represent the heavens or infinity, and our hearts(Shen/spirit) are what tie heaven and earth together in our earthly lives. Our hearts, in my opinion, can discover the unseen paths, or invisible threads, that lead us to our spiritual destinies.
Again, a lot of this I have synthesized from various sources, and it is also partly intuitive or poetic reasoning. Take it or leave it, but thanks for asking.
Mara
