||according to the 2016 update) galaxies, 1021 stars, 1078 atoms, 1088 photons. There is a hierarchy of structure: Everything is composed of smaller things and is a part of something larger as shown in Figure 02-01a (See also "Map of the Universe" for a different perspective) and Figure 15-01. The characteristics of structures in different scale changes according to the interplay of various physical forces. Quantum phenomena control the small scales, while gravity dominates on large scales, and both come into play at the beginning of the universe. On each scale of size there is a corresponding scale of time: processes tend to happen quickly on small scales and slower on the larger ones.