8th sphere Steiner
    “By the Middle Ages, people saw in the stars only what their physical eyes could perceive: the sphere of Venus, the sphere of the sun, of Mars, and so on up to the sphere of the firmament of fixed stars. Beyond that, they believed, there was the eighth sphere which enclosed the others like a solid blue wall around them ... Modern astronomy began to develop as a science when Copernicus started to think about what exists in the universe beyond the range of human sensory perception. In fact, it is true of all the sciences that they developed in opposition to sensory appearance. When Copernicus explained that what we see is maya, illusion, and that we should rely on what we cannot see — that was the moment when science as we know it today began.” — Rudolf Steiner, THE SPIRITUAL GUIDANCE OF THE INDIVIDUAL AND HUMANITY (Anthroposophic Press, 1992), lecture 3, GA 15. In passing, we should note that Steiner’s statement about modern science is grossly misleading. Scientists certainly do focus on what they can perceive, although they often need instruments to extend their powers of perception. Science does not (as Steiner goes on to argue) lead inevitably to the recognition of supersensible realms of the sort he described. 
“If we disregard the human being for a moment and consider those beings which we always have called, in the order of the hierarchies standing above us, the Spirits of Form, the Creative Form Beings, then we shall have to say that we, as human beings, shall only reach the sphere which we ascribe to our Divine Creator Beings when the Earth has passed through three further stages of evolution, which you will find designated in my OCCULT SCIENCE  as Jupiter stage, Venus stage and Vulcan stage, and shall have reached the eighth stage. Thus these Creative Spirits are at the stage which we human beings shall have reached after the Vulcan evolution. This is their sphere which belongs to them just as the fourth sphere belongs to us. But we must think of these spheres as being inserted into one another, as interpenetrating one another. Thus, is I designate the sphere of which I have just spoken as the eighth sphere, we do not live only in the fourth but also in this eighth sphere through the fact that our Divine Creators live in this sphere together with us.” — Rudolf Steiner, THE MISSION OF THE ARCHANGEL MICHAEL (Anthroposophic Press, 1961), lecture 3, GA 194.
“You know that human evolution takes its course through the seven spheres of Saturn, Sun, Moon, Earth, Jupiter, Venus, Vulcan. We will conceive that besides these seven spheres there is still something else which lies outside them and yet is in some way related to the Earth. Here, then, we have a sphere, visible only to visionary-imaginative clairvoyance, which stands there as an Eighth Sphere over and above the seven which constitute the domain of the ordered and regular evolution of mankind.” — Rudolf Steiner, THE OCCULT MOVEMENT IN THE NINETEENTH CENTURY (Rudolf Steiner Press, 1973), lecture 5, GA 254.
“[T]he Eighth Sphere is to be observed within the Earth Sphere. It cannot properly be drawn either above or below ... [J]ust as the spiritual is round about us, so we must also look for the Eighth Sphere in our environment. This means that an organ enabling man to perceive the Eighth Sphere would have to be developed, just as his physical senses enable him to perceive the material Earth ... [I]f we have developed an organ for experiencing the Eighth Sphere, we are conscious of it around us. So that if the Eighth Sphere is to be described, it must obviously be described as a realm in which we are living all the time.” — Ibid.
“On the Old Moon certain pictures were present. These should have passed over to the Earth as something everywhere perceptible. But Lucifer and Ahriman retained them for themselves. Lucifer and Ahriman wrested from the Earth certain of its constituents and made them into Imaginations, so that these Earth-substances became, not Earthly formations, but Moon formations. Into our Fourth Sphere, therefore, there has been instilled a sphere that is really a Moon-sphere, but is filled with Earthly substantiality and is therefore a bogus creation in the Universe. To the seven Spheres, an Eighth, created in opposition to the progressive Spirits, has been added. The necessary consequence of this is that the Spirits of Form must do battle on the Earth for every morsel of substantiality capable of mineralisation, lest it should be wrested from them by Lucifer and Ahriman and borne into the Eighth Sphere ... All earthly being and existence are involved here. Lucifer and Ahriman strive unceasingly to draw from the Earth's substances whatever they can snatch, in order to form their Eighth Sphere which then, when it is sufficiently advanced, will be detached from the Earth and go its own way in the Cosmos together with Lucifer and Ahriman. Needless to say, the Earth would then pass over to Jupiter as a mere torso ... Therefore we ourselves are involved in the battle. Lucifer and Ahriman battle against the Spirits of Form, with the aim of wresting mineral substance from us everywhere.” — Ibid.
“The formation of our skull is due to the fact that it is there that most has been wrested from us. Hence it is precisely through the head that we can emancipate ourselves from our organism to the greatest extent. We can soar upwards in thoughts, we can distinguish between the good and the evil. And for that very reason, Lucifer and Ahriman have there been the most successful in wresting away substantiality; in the so-called noblest organ of man they have been able to wrest away the greatest amount of mineralised substantiality. This alchemy by which mineral substance is sent over into the Eighth Sphere is taking place all the time behind the scenes of our existence.
 “... If everything were to run without a hitch for Lucifer and Ahriman, if they were everywhere able to wrest as much as they wrest from the organ of the head, Earth-evolution would soon reach a point where Lucifer and Ahriman could succeed in destroying our Earth and in leading over all evolution of worlds into the Eighth Sphere, so that Earth-evolution as a whole would take a different course. Hence Lucifer endeavours to unfold his greatest strength of all at the place where man is the most vulnerable, namely, in his head. The stronghold which it is easiest for Lucifer to capture is the human head; and everything that is similar to the head in respect of the distribution of the mineral element, so that it can be drawn out in the same way, is equally exposed to the danger of being despatched into the Eighth Sphere. No less a prospect looms as a consequence of this intention of Lucifer and Ahriman than that the whole evolution of humanity may be allowed to disappear into the Eighth Sphere, so that this evolution would take a different course.” — Ibid.
“[M]an is perpetually exposed to the danger of having his free will wrested from him and dragged by Lucifer and Ahriman into the Eighth Sphere. This happens if the element of free will is transformed, for example, into visionary clairvoyance. When this is the case, a man is already in the Eighth Sphere. This is a matter of which occultists are so reluctant to speak, because it is an awful, terrible truth. The moment the free will is transformed into visionary clairvoyance, what unfolds in the human being becomes the booty of Lucifer and Ahriman. It is immediately captured by them and thereby spirited away from the Earth. You can see from this how, through the shackling of free will, the spectres of the Eighth Sphere are created. Lucifer and Ahriman are engaged perpetually in shackling man's free will and in conjuring all sorts of things before him in order to tear away what he makes out of these things and let it disappear in the Eighth Sphere ... This devilish plan — for here we have indeed to do with the devil — was put into effect by Lucifer and Ahriman when it had occurred to occultists to endeavour to accomplish something through mediumship. Lucifer and Ahriman inspired the mediums through whom they arranged the whole business, in order that people might be guided to the realm whence the dead were alleged to be speaking. Lucifer and Ahriman could then lay hold of their souls. The occultists were alarmed when they saw what course things were taking and they took counsel among themselves as to how to steer away from it. Even those who belonged to the left wing realised what was happening, and they said: we will do something different!” — Ibid. Note: “Visionary clairvoyance,” which is false, must be distinguished from Steiner’s own “exact clairvoyance,” which is true, true, true.
“Asuras [other demons, as it were] are spirits of the very greatest egoism who remained behind during Saturn evolution. They want to condense matter and compress it ever more so that it can't be spiritualized and brought back to its original condition. They're the dregs of the planetary evolution that goes form Saturn to Vulcan. The asuras inhabit the moon and from there they work on the men whom they want to drag down into the eighth sphere and thereby tear away from progressive evolution and its goal — the Christ. All those who strive towards the eighth sphere will eventually live on a moon.” — Rudolf Steiner, FROM THE CONTENTS OF ESOTERIC CLASSES (transcript, Rudolf Steiner Archive), GA 266.
    “[O]nly those who are willing to see human beings pass into the Eighth Sphere can have any valid objection to this spiritual-scientific Movement.” — THE OCCULT MOVEMENT IN THE NINETEENTH CENTURY.
    “To present this correctly, we must show the Earth here, and the Eighth Sphere here (see diagram). The Eighth Sphere belongs to our physical Earth in the sense indicated. We are surrounded everywhere by the Imaginations into which the aim is that mineral materiality shall continually be drawn. There lies the reason for the sacrifice made by Jahve or Jehovah — the precipitation of substance far denser than the other mineralised substance. This was established by Jahve as Moon, as the counteracting agent. It was substance of extreme density — and this density was described by Sinnett* as substance of a far denser physical-mineral character than exists anywhere on the Earth. Hence Lucifer and Ahriman cannot dissolve it away into their world of Imaginations. And so this Moon circles around as a globe of dense matter, solid, dense, indestructible. If you read carefully enough you will find that even the descriptions of the Moon given by physicists tally with this. Everything that was available on the Earth was drawn out and placed there in order that there should be enough physical matter incapable of being wrested away. When we look at the Moon, we see there in the Universe a substance far more intensely mineralised, far physically denser, than exists anywhere on the Earth. Jahve or Jehovah, then, must be regarded as that Being who even in the physical domain has ensured that not all materiality can be drawn away by Lucifer and Ahriman. And then, at the right time, equal care will be taken by the same Spirit that the Moon shall re-enter the Earth when the Earth is strong enough to receive it, when the danger is averted by the development that has meanwhile taken place.” — Rudolf Steiner, THE OCCULT MOVEMENT IN THE NINETEENTH CENTURY, p. 87. [R.R. sketch, 2010, based on the one in the text. The large red expanse is the Eighth Sphere, enveloping the green Earth and the gray Moon.]
    "Asuras: the beings that strive for the eighth sphere. They want to condense matter, increasingly to press it together, so to speak, so that it cannot be spiritualized again, that is, led back to its original state. They are the 'dregs' of the entire planetary evolution, which begins with Saturn and goes through the Sun, Moon, Earth, Jupiter, Venus, Vulcan. The Asuras already inhabit the Moon and influence human beings, whom they wish to pull down into the eighth sphere and thus tear them away from progressive evolution and their goal — the Christ. All who are striving toward the eighth sphere will ultimately find their existence on a moon (Jupiter)." — Rudolf Steiner, ESOTERIC LESSONS 1904-1909 (SteinerBooks, 2007), p. 167. [R.R. sketch, 2013.]
    “You know that human evolution takes its course through the seven spheres of Saturn, Sun, Moon, Earth, Jupiter, Venus, Vulcan. We will conceive that besides these seven spheres there is still something else which lies outside them and yet is in some way related to the Earth. Here, then, we have a sphere, visible only to visionary-imaginative clairvoyance, which stands there as an Eighth Sphere over and above the seven which constitute the domain of the ordered and regular evolution of mankind ... Luciferic and Ahrimanic spirits [i.e., minions of the arch-demons Lucifer and Ahriman] are at work — and they hold back for themselves something of the Old Moon substantiality, wrest it away, as it were, from the Spirits of Form [i.e., gods four levels above humanity]. The fact that Lucifer and Ahriman do so is indicative of their essential nature. Thus as Sphere Three is advancing to a further stage, something is wrested from the Spirits of Form by Lucifer and Ahriman; into this part that is wrested away, Lucifer and Ahriman penetrate, instead of the Spirits of Form. The activities of Lucifer and Ahriman are added to those of the Spirits of Movement [i.e., gods five levels above humanity] and, as a result, [Sphere] Eight arises out of [Sphere] Three.” — Rudolf Steiner, THE OCCULT MOVEMENT IN THE NINETEENTH CENTURY (Rudolf Steiner Press, 1973), pp. 80-84.