This paper takes a light-hearted look at how far one can go in applying primary world science to Middle-earth. Tolkien purists and physics purists may wish to pass over this!
Coombs, Jenny and Read, Marc
"A Physics of Middle-earth,"
Mythlore: A Journal of J.R.R. Tolkien, C.S. Lewis, Charles Williams, and Mythopoeic Literature: Vol. 21
, Article 48.
Available at: https://dc.swosu.edu/mythlore/vol21/iss2/48