# universal attraction

#### A Basic Planetary System – video preview

Since not everybody has Excel and more and more people are on the dumbed down new versions (2007 and 2010) I am presenting these previews to give the readers a feel of the real speed and feel of some of the models in older Excel versions (in this case 2003). This preview refers to an older model. [sociallocker][/sociallocker]

#### A Legacy 3D Octal Planetary Model

This is an older model of planetary motion in 3D containing eight planets. A video preview can be watched here. [sociallocker][/sociallocker]

#### A basic 3-body Planetary System

Hi folks, as a continuation to the previous tutorial here is a 3-body planetary model where the solution to the equations is contained in a static form, as a lookup table (I previously called it a “pure spreadsheet solution”). The model is static in the sense that after any parameter is changed, the solution data remains unchanged in a table until a new parameter is updated by the user. The display is dynamic however since an “Offset()” function…

#### How to Model a Basic 2-body Planetary System

Here is a tutorial explaining how to model a two dimensional 2-body planetary system in Excel. It uses the Euler method of integration. The tutorial starts with explaining the simple newtonial laws acting on the two planets. There are essentially just two forces acting on each body at any time: the inertia and the gravitational attraction. During each small time step, from the distance between bodies we can calculate the gravitational…

#### 3-Body Planetary System with Options

Here is a 3-body system with 3D graphics. I made it about 2 years ago but I’ve been updating it lately. This model works at about 30 frames/second in Excel 2003 on a modern PC. In Excel 2007 it will run 10-15 times slower. I know 2010 is a lot faster than 2007. I’ve just bought a legit copy for 50$ but I didn’t have a chance to install it yet. I need to add few more features….

#### Basic Planetary Simulator

This is an Excel workbook containing a dynamic model of a basic binary planetary system. [sociallocker][/sociallocker]