1.1 The Scale of the Universe a relatively small universe. This idea made sense at a time when understanding was b ilt upon everyday experience. After all, we cannot feel the constant …

But to demonstrate the immense number of stars in the universe, we need a freight train with hopper cars filled with sand. As the train begins to speed by us at a level crossing, we count …

This chapter provides an overview of the Universe and the study of astronomy that will follow in subsequent chapters. You will look at astronomy from multiple perspectives, as a science, …

We have now seen all the way out to the edge of the observable universe, found millions of galaxies beyond our own, and have a coherent description of how our own Solar System, in …

Biggest unanswered questions: “Flatness” problem: why is the density in the Universe almost critical? “Horizon” problem: why is the large scale of the Universe so smooth?

Our universe extends staggeringly far beyond our own earthly environment. Trying to grasp the size in any meaningful way is bound to make your brain hurt. We can make analogies to at …

The special relativity process of Energy, Dark Energy, Matter and Dark Matter explain the universe how to origin and evaluation as well as how does the universe work.