What is with George Lucas and bottomless pits?
 

vaginas?

In all fairness, one bottomless pit was actually a sarlacc.

Lucas' next movie: A Sarlacc in Guatemala.
http://designly.net/wp-content/uploa...la-sarlacc.png

This symbolizes a universal struggle that Lucas has experienced as a teenager in which he often had to fight with his friends over who would take one for the team by fucking the ugly girl. He likens the heroes to himself and the Sith to his friends while the bottomless pit/monster epitomizes the ugly fat girl.

The Death Star represents his desire for sexual gratification that goes unfulfilled which we might call "Blue Balls".

And you may have guessed that the lightsabers which grow straight and fully erect, are a manifestation of Lucas' desire to not have erectile dysfunction.

There were no bottomless pits in the battle of Hoth. But I imagine that's just because there weren't any pits big enough for an AT-AT to fall into.