Cornelius Agrippa in his Three Books of Occult Philosophy (book I, chapter 8; book II, chapter 7) relates the four elements to the celestial objects, namely the planets, mostly because magicians like to figure out what can stand in for what in different contexts.  According to Agrippa, Earth is the element that basically allows all of Creation to be created (book I, chapter 5):

Now the Basis, and foundation of all the Elements, is the Earth, for that is the object, subject, and receptacle of all Celestiall rayes, and influencies; in it are contained the seeds, and Seminall vertues of all things; and therefore it is said to be Animall, Vegetable, and Minerall. It being made fruitfull by the other Elements, and the Heavens, brings forth all things of it self; It receives the abundance of all things, and is, as it were the first fountain, from whence all things spring, it is the Center, foundation, and mother of all things…It is the first matter of our Creation, and the truest Medicine that can restore, and preserve us.

Agrippa makes a connection between Earth and the Moon and the fixed stars, indicating how the element of Earth can be reflected in the skies.  I mentioned this briefly before, focusing mostly on the connection between elemental Earth and planetary Moon:

…the heaven of the Moon is the closest to Earth, making it the most dense of the seven planets.  As the most dense planet, it’s the last stop for an Idea coming from the sphere of the Prime Mover through the stars and the other planets to finally come into form; this is the sphere where something actually takes a materialized shape, even if it’s only illusory and ephemeral.  This is also shown since, as the fastest moving planet and the lowest rung on the ladder, it collects the rays and forces of all the other planets and influences above it, focusing them like a lens onto the Earth…Like the element of Earth, which takes form and receives the influences of the other elements, the Moon takes form and receives the influences of the other planets.

The connection between the terrestrial sphere of Earth and the celestial sphere of the fixed stars is a little more difficult for me to rationalize.  I suppose I’ve been going on the notion that, just as Earth is the most stable and immovable of the elements, so too are the fixed stars the most stable and immovable of the celestial objects referenced in magic.  After all, they don’t really move much (at an extremely slow rate, not counting the negligible effect the motion of the fixed stars have to each other), especially compared to the otherwise rapid motion of the wandering stars (a.k.a. planets).  Beyond that, I never really thought about it much.  I’ve got some other work before I get up and running with the sphere of the fixed stars, so I haven’t actually gone up to call Iophiel (or Raziel, depending on the text).

Recently, I was chatting with Auriel, the archangelic king of the sphere of Earth, and after the usual friendly chat, catching up over a glass of wine in a circle, and empowerment of myself and my sphere with the element of Earth, we sat down and started talking about what Earth is really like at length and in depth.  As usual, “as above so below” is a good rule to go by, and Auriel instructed me to take a look at the Tree of Life a little more closely, especially between the sephiroth of Malkuth and Kether.  For one, everything in the sphere of the Earth, the sephirah of Malkuth, has at least a little Earth in it; that’s why the elemental colors of Malkuth are “dim” or murky, to show that they’re not the pure elements in their ideal form.  Malkuth is the physical, material universe, the one that modern atheistic scientism holds is the only thing that exists.  On the other hand, Kether is unmanifest infinity, divinely simple in that everything that is, was, will be, isn’t, was never, can never, and may be is all One Thing.

Without Earth, nothing can have a material basis; it’s the only element that can’t combine on its own with itself, but can combine with itself through the use of other elements that it’s blended with.  Earth, for instance, can offer a basis for Fire to burn, a course for Air to flow over, or a container for Water to fill, but Earth cannot do anything with Earth on its own.  Because of this, it’s more than just convenience that everything on Earth is at least partially made of Earth, both sharing the same name.  Earth is the most malleable of elements, and takes the influence from everything above it.  Earth is the key to manifestation; without it, much like in the geomantic figure Cauda Draconis, everything passes away from and nothing can be brought into material reality.  Without Earth, the bottom drops out quite literally.

The highest sephirah is Kether, the Crown, which is basically the starting point for infinity from finite existence, the place where finite reality stops having an end and starts having no end and no limit at all.  Though it has the qabbalistic path number of one, and though I don’t have much experience to talk about it, I feel like this is somewhat misleading.  Although one is computationally the root of all numbers, Kether includes all things that exist as well as all things that don’t exist.  In that sense, Kether might be better termed i or something.  Things don’t really start to begin the process of manifestation until an Idea from the Infinite Mind, a Ray from the Infinite Light passes through the second sephirah called Chokmah, the sphere of the fixed stars.  There, something finally makes the jump from “possibility of manifestation” to “manifesting”, where things actually start to legitimately make the claim of existing.  The fall from grace, the first step of the Fool is just the first step in the Chain of Manifestation, but it’s still progress all the same.

The sphere of the fixed stars allows only rays of light that come from the sphere of the Prime Mover; these rays pass through the darkness of the Fool’s cliff and are filtered through the stars in constellations or particular regions of the sky, and appear to us down on Earth as starlight.  Without that filter to provide form, infinite possibility could never be whittled down to probable possibility.  It is this pure Light, filtered through the eighth sphere, that can take on shape or form or purpose later on based on its Idea above.  The fixed stars take on the influence and nature of the Light above it and pass it down into the world as the beginning of Creation.

The similarities between Kether and Chokmah, or the spheres of the Prime Mover and the fixed stars, with Yesod and Malkuth, or the spheres of the Moon and the Earth, now become apparent.  The Moon and Infinite Light both provide an imagined substance to be manifested in the realm beneath it; the Earth supplies a concrete, manifested form based on the imaged and astral form from the Moon, while the fixed stars supply a viable, manifesting Idea based on the unbound and divine Idea from the Source.  The difference between King and Kingdom lies in where and how things come to be.  Just as the fixed stars provide realization for an idea to manifest something at the beginning, Earth provides substance for form to manifest something at the end.  It’s this ability to turn undefined, vague things into clear(er), specific things that relates the fixed stars to the Earth.

At least, that’s my opinion for now.  Though much can be said of the stars and planets and elements in writing, especially in terms of theory and cosmology, working with magic is still a mystery: it requires working with and experience to really grok the whole shebang.  But I’ll go with Auriel’s guidance for now.