What is the plauseable age of Arda?

[jammi567]

Do we have any clue to the age ofthat world? I know it's impossible to accurately work out, but a rough estimate would be a fun thing to debate over.

[Keith K]

David Day, in Tolkien, The Illustrated Encyclopedia figures the total age of Arda to be in the neighborhood of 37,000 years at the end of the Third Age.