7th Dimension Description

The 7th Dimension was skipped in the Alteriian colonization efforts due to a low amount of metallaic materials, a low amount of organic life, a low amount of life-bearing planets, and a low general value of anything. The remote scientific and military outposts the Alteriians constructed were just that, military and scientific outposts.

Of the positives of this dimension include that it is highly defensible, if not in a strategic location. The vast amount of asteroids (mostly made up of ice, carbon, and nickle) create a confusing morass of movement throughout the entire dimension, which gives defensive forces the ability to create an ambush out of virtually whatever they wanted to, whenever and where-ever they want to.
A secondary effect of all this icy movement is the natural beauty of the entire dimensions. With most of the dimension possessing blue and purple stars, the reflections of light off of the varying asteroids creates an astronomically (pun intended) beautiful and wondrous view.
The Seventh dimension is also comprised of various non-metals of limited use, including entire planets with atmospheres of non-reactive Xenon (which creates a yellow-ish pale on the asteroids) and entire star systems made up of mostly chlorine, calcium, and manganese.

All in all, the system is of low economic use, low strategic use, but has plenty of space and mostly useless but relatively rare materials.

And the outstanding view of course.