Flat Earthers

[Gilrandir]

That works only until you look at the days and compare with known physics:
http://bibleview.org/en/bible/genesis/7days/
Day 1: Day and night
Day 4: Stars, sun and moon

How can there be day and night when there is no sun?
That goes against all physical evidence and I just picked the most striking example for now.

Perhaps there were other sources of light:

And as they watched, upon the mound there came forth two slender shoots; and silence was over all the world in that hour, nor was there any other sound save the chanting of Yavanna. Under her song the saplings grew and became fair and tail, and came to flower; and thus there awoke in the world the Two Trees of Valinor. Of all things which Yavanna made they have most renown, and about their fate all the tales of the Elder Days are woven.
The one had leaves of dark green that beneath were as shining silver, and from each of his countless flowers a dew of silver light was ever falling, and the earth beneath was dappled with the shadow of his fluttering leaves. The other bore leaves of a young green like the new-opened beech; their edges were of glittering gold. Flowers swung upon her branches in clusters of yellow flame, formed each to a glowing horn that spilled a golden rain upon the ground; and from the blossom of that tree there came forth warmth and a great light. Telperion the one was called in Valinor, and Silpion, and Ninquelótё, and many other names; but Laurelin the other was, and Malinalda, and Culúrien, and many names in song beside.
In seven hours the glory of each tree waxed to full and waned again to naught; and each awoke once more to life an hour before the other ceased to shine. Thus in Valinor twice every day there came a gentle hour of softer light when both trees were faint and their gold and silver beams were mingled. Telperion was the elder of the trees and came first to full stature and to bloom; and that first hour in which he shone, the white glimmer of a silver dawn, the Valar reckoned not into the tale of hours, but named it the Opening Hour, and counted from it the ages of their reign in Valinor. Therefore at the sixth hour of the First Day, and of all the joyful days thereafter, until the Darkening of Valinor, Telperion ceased his time of flower; and at the twelfth hour Laurelin her blossoming. And each day of the Valar in Aman contained twelve hours, and ended with the second mingling of the lights, in which Laurelin was waning but Telperion was waxing. But the light that was spilled from the trees endured long, ere it was taken up into the airs or sank down into the earth; and the dews of Telperion and the rain that fell from Laurelin Varda hoarded in great vats like shining lakes, that were to all the land of the Valar as wells of water and of light. Thus began the Days of the Bliss of Valinor; and thus began also the Count of Time.

(Tolkien J. R. R. The Silmarillion. – Boston: Houghton Mifflin Company, 1977. – 365 p.)

On a more serious note, the light referred to in Genesis might have been sourceless (just like when it it arleady light in the early morning but there's no dawn yet), and later it was embodied into a special container aka the Sun.