Region: Middle Earth
That's intersting The LOTR Nation of Tatarica! I'd never thought of the world being round the whole time (but then again, I've only read one of the History of Middle Earth books). Would this also imply that other related stories, such as the way the sun and moon are created, are similarly simplified by men?
Another way to explain the way I see Valinor is maybe not so much as IN outer-space but before it... If "outer-space" is the Void, the one must enter it through the Door of Night, which is in Valinor. We know that it is traversable (at least to my understanding) since Earendil sails in it, along with the Maiar that control the sun and moon, and that is why his Silmaril can be seen as a star. So my understanding is that Valinor is off of the planet, but since the Void/outer-space must be entered though Valinor, then Valinor is between the two.