Could Eru change the very laws of nature if he wanted to?

[Morthoron]

Although Jallanite should never consider a career in politics or customer service, he has, in his brusque manner, reiterated Tolkien's later views on ME's mythic cosmogony. Here, Tolkien refers to the 'straight road' to Valinor and the separation of the mortal plane and the Undying Lands:

J.R.R. Tolkien, Letter 135, 24 July 1971
This general idea lies behind the events of The Lord of the Rings and the Silmarillion, but is not put forward as geologically or astronomically 'true'; except that some special physical catastrophe is supposed to lie behind the legends and marked the first stage in the succession of Man to dominion of the world. But the legends are mainly of 'Mannish' origin blended with those of the Sindar (Gray-elves) and others who had never left Middle-earth.