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I doubt that it's Mars. Grond 18:42, 27 December 2009 (UTC)

I believe it is mentioned somewhere, but if it's going in the article, it's going to need a source. --Ederchil (Talk/Contribs/Edits) 19:16, 27 December 2009 (UTC)
I've looked it up, and have seen it mentioned a few time. Perhaps it can be added to the article worded as "Some speculate that..." or something similar. Grond 21:22, 27 December 2009 (UTC)
Christopher Tolkien explicitly identified Carnil (or Karnil as it originally was) with Mars. The Index in Morgoth's Ring says (in my paperback edition), "Karnil The planet Mars. 160, 166; Carnil 166. See pp. 434-5." In the note on pages 434-5 it says how Tolkien wrote an "M." above Karnil, identifying it with Mars and a couple of paragraphs below this Christopher says the following things:-
"...a great red star named Karnil and marked with 'M' must be Mars (cf. Michael Ramer's name Karan for Mars, IX220)" then, "That Mars and Jupiter, if not Saturn, should appear among them [that is the conspicuous objects of the heavens of Arda] would seem inevitable, seeing that in my father's astronomical myth the planets were never distinguished from the 'fixed stars' " and finally, and most crucially, "Karnil was surely always Mars".
In my mind there is absolutely no doubt as to what Carnil is. A good online source for astronomy would be the Astronomy of Middle-earth by Kristine Larsen who has written a few articles on Middle-earth astronomy is somewhat of an expert on the issue. --Mith (Talk/Contribs/Edits) 21:27, 27 December 2009 (UTC)