Answer: how the Milky Way galaxy appears
Step-by-step explanation:
The Milky Way galaxy of which earth is a part of, is a spiral galaxy. This means that it appears as if it is a disk where the various components such as the stars, plants, gas and dust rotate around a central concentration of stars in the middle called the bulge.
This is what Cassandra was modelling. The glitter depicts the stars, gas and dust and the spot where she removed her finger is the bulge.