An analysis of attempts by fans (including scientists) to either ascribe a Real World date or a consistent Secondary World date to the fictional luni-solar holiday "Durin's Day" in The Hobbit demonstrates the value of such "scientific fan fiction." In particular, such endeavors can increase the scientific knowledge of both the fan-author and audience. These examples can also be used in the classroom or outreach to demonstrate both the impressive level of Tolkien's integration of real-world science in his sub-creation of Middle-earth, as well as highlight the limitations of Tolkien's understanding (an educational endeavor in and of itself).
"Deconstructing Durin’s Day: Science, Scientific Fan Fiction, and the Fan-Scholar,"
Journal of Tolkien Research: Vol. 8:
1, Article 3.
Available at: https://scholar.valpo.edu/journaloftolkienresearch/vol8/iss1/3