In the top row of buttons in the main window, near the middle, just above the right side of the button for "20 Minutes" increment length, is a button that looks like a map of a solar system.
Click that (or hit F9) and you will open the System View window, wherein you can peruse details on every body in the known galaxy.
Sidenote: go ahead and click all of those buttons in the top row, one at a time, and make a mental note of the wonders revealed by each one.