The moon's formation

[Fireball]

*sigh*  Such usually bright people, and I have to educate you.  Pay heed:

When Morgoth and Ungoliant destroyed the Two Trees, the tears of Nienna caused the withered trees to produce a single fruit and a single flower.  The last fruit of Laurelin was placed in a vessel guided by Maia Arian and became the sun.  The last flower of Telperion was placed in a similar vessel and became the moon.  This vessel was guided by another Maia (Tilion).  But Tilion was erratic and guided the moon-vessel in a haphazard fashion.  This was because he was in love with Arian, but - because of her great heat - could not reach her.  He came perilously close a few times, and is marred because of it.  Tilion's erratic path and his love for Arian explains why the sun is seen every day, but the moos isn't, and why both can sometimes be seen in the sky at the same time.

And enough about tides.  Those are cause by Ulmo and Osse, and that's a completely different story.  So there.

Boru

Finally, a logical, believable explanation!