I'll walk you through what qualifies as a planet, how the Solar System likely formed, how the planets organize into meaningful “architectural layers,” and what makes each planet distinct—size, composition, atmosphere, rotation, temperatures, and moons. In another effort to bring these vast distances down to Earth, we've shrunk the solar system down to the size of a football field. Needless to say, our solar system doesn't fit real well on paper — or a Web site. Pluto is very far away! The purpose of today's lab is to allow you to develop a better appreciation for the distances between the largest objects in our solar system, and the physical sizes of these objects rela-tive to each other. That means the Sun will be on the 0-yard line, and Pluto is at the 100-yard line. The system formed about 4. 6 billion years ago when a dense region of a molecular cloud collapsed, creating the Sun and a protoplanetary disc. If you're building anything from an animation to a game mechanic to a scientific notebook, you need two things: (1) a correct mental model of what the eight planets actually are, and (2) a pragmatic way to represent them without lying to your users (or to yourself) via oversimplified assumptions.