Eclipse vs. "Sun Blocked"

[Unknown Zombie]

I'm trying to edit a new scenario where it's always dark, or at least never fully bright. It's an attempt to recreate a situation where the colonists crash-land on the dark side of a tidally-locked planet.

In the permanent game conditions list there are options for "eclipse" and "sun blocked." In reality, an eclipse is a blocked sun -- so what's the difference in game mechanics between these two things?

I've played games where eclipses happen so I have an idea what they bring to the game, but I don't think I've ever seen a "sun blocked" event happen. 🤔

The game just describes it as some unknown device blocking the sun, but is there more to it than that? Just a reskinned eclipse?