Nebula

Nebula allow us to evaluate baryonic motion. 

Credit NASA

These are dynamic systems that change over time. We need to see the Messier or other catalog change over time. We will see the different types of motion.

A 3d view of this would be cool. 3d spectra view over time would rock!

I look at that picture and see clouds in a line.

M1 changes constantly. Credit NASA