from Morgoth's Ring, Athrobeth Finrod ah Andreth, author's note 2
Arda, or 'The Kingdom of Arda' (as being directly under the kingship of
Eru's vice-gerent
Manwe) is not easy to translate, since neither 'earth' nor 'world' are entirely suitable. Physically Arda was what we should call the Solar System.(11) Presumably the Eldar could have had as much and as accurate information concerning this, its structure, origin, and its relation to the rest of Ea (the Universe) as they could comprehend. Probably those who were interested did acquire this knowledge. Not all the Eldar were interested in everything; most of them concentrated their attention on (or as they said 'were in love with') the Earth.
The traditions here referred to have come down from the Eldar of the
First Age, through
Elves who never were directly acquainted with the
Valar, and through
Men who received 'lore' from the Elves, but who had myths and cosmogonic legends, and astronomical guesses, of their own. There is, however, nothing in them that seriously conflicts with present human notions of the Solar System, and its size and position relative to the Universe. It must be remembered, however, that it does not necessarily follow that 'True Information' concerning Arda (such as the ancient Eldar might have received from the Valar) must agree with Men's present theories. Also, the Eldar (and the Valar) were not overwhelmed or even principally impressed by notions of size and distance. Their interest, certainly the interest of
the Silmarillion and all related matter, may be termed 'dramatic'.
Places or worlds were interesting or important because of what happened in them.
It is certainly the case with the
Elvish traditions that the principal part of Arda was the Earth (Imbar 'The Habitation'),(12) as the scene of the Drama of the war of the Valar and the Children of Eru with
Melkor: so that loosely used Arda often seems to mean the Earth: and that from this point of view the function of the Solar System was to make possible the existence of Imbar.
With regard to the relation of Arda to Ea, the assertion that the principal demiurgic
Ainur (the Valar), including the originally greatest of all, Melkor, had taken up their 'residence' in Arda,(13) ever since its establishment, also implies that however minute Arda was dramatically the chief point in Ea.
These views are not mathematical or astronomical, or even biological, and so cannot be held necessarily to conflict with the theories of our physical sciences. We cannot say that there 'must' be elsewhere in Ea other solar systems 'like' Arda, still less that, if there are, they or any one of them must contain a parallel to Imbar. We cannot even say that these things are mathematically very 'likely'. But even if the presence elsewhere in Ea of biological 'life' was demonstrable, it would not invalidate the Elvish view that Arda (at least while it endures) is the dramatic centre. The demonstration that there existed elsewhere Incarnates, parallel to the Children of Eru, would of course modify the picture, though not wholly invalidate it. The Elvish answer would probably be: 'Well, that is another Tale. It is not our Tale. Eru can no doubt bring to pass more than one.
Not everything is adumbrated in the
Ainulindale'; or the Ainulindale' may have a wider reference than we knew: other dramas, like in kind if different in process and result, may have gone on in Ea, or may yet go on.' But they would certainly add: 'But they are not going on now. The drama of Arda is the present concern of Ea.' Actually it is plainly the view of the Elvish tradition that the Drama of Arda is unique. We cannot at present assert that this is untrue.
The Elves were of course primarily and deeply (more deeply than Men) concerned with Arda, and Imbar in particular. They appear to have held that the physical universe, Ea, had a beginning and would have an end: that it was limited and finite in all dimensions. They certainly held that all things or 'makings', that is constructed (however simply and incipiently) from basic matter, which they called erma,(14) were impermanent, within Ea. They were therefore much concerned with 'The End of Arda'. They knew themselves to be limited by Arda; but the length of its existence they do not seem to have known. Possibly the Valar did not know. More probably, they were not informed by the will or design of Eru, who appears in the Elvish tradition to demand two things from His Children (of either Kindred): belief in Him, and proceeding from that, hope or trust in Him (called by the Eldar estel).
But in any case, whether adumbrated in the Music or not, the End could be brought about by Eru at any time by intervention, so that it could not be certainly foreseen. (A minor and as it were foreshadowing intervention of this sort was the catastrophe in which
Numenor was obliterated, and the physical residence of the Valar in Imbar was ended.) The Elvish conception of the End was in fact catastrophic. They did not think that Arda (or at any rate Imbar) would just run down into lifeless inanition. But this conception was not embodied by them in any myth or legend. See Note 7.