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 …

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, …

Once the two galaxies are next to each other, you've reached the early universe! Pull on the bottom of the paper to expand the universe and move the galaxies apart over time.

The Universe is homogeneous and isotropic on large scales [Image from “The Physical Universe” by F. Shu] Solutions to Einsteins’ field equations for an homogeneous and isotropic Universe …

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 …

Using our own ingenuity, humanity is probing the depths of the Universe and trying to unravel its mysteries, from our tiny, home planet, Earth. The visible Universe contains billions of galaxies, …

In this simple model the universe typically grows 101000000000000 times during inflation. Now we can see just a tiny part of the universe of size ct = 1010 light yrs. That is why the universe …