There already are a number of questions which discuss the relationship between "our world" and Middle-earth.
I am interested in the astronomy of Middle-earth, which I guess could possibly have discussed in some book. I am currently re-reading the LotR (I highly recommend to read it multiple times, and I feel to be not alone with this idea :) ) and am noticing a lot of nice details. Among these, there is this description at the end of Three is company:
Away high in the East swung Remmirath, the Netted Stars, and slowly above the mists red
Borgil rose, glowing like a jewel of fire. Then by some shift of airs all the mist was
drawn away like a veil, and there leaned up, as he climbed over the rim of the world,
the Swordsman of the SKy, Menelvagor whith his Shining belt.
Menelvagor with his Shining Belt could be Orion. This is consistent with the time of the year (autumn in the northern hemisphere). Is it possible to identify the other stars or planets? (Borgil, with a red hue, could be Mars).