Diameter is used to describe the sizes of planets and moons. The diameter is used in game to determine the following:

  • Number of fields on a planet
  • Number of fields on a moon
  • The outcome of an attempt to destroy a moon with Death Stars

The formula for the number of fields on a planet or moon is:

  • $ \left(\frac{\mathrm{Diameter}}{1000}\right)^2 $

This result is rounded down (for example, 25.629 becomes 25 fields.) In addition, your home planet is always 163 fields regardless of diameter.

When attacking a moon with one or more Death Stars, the chance that the moon will be destroyed is:

  • $ (100-\sqrt{\mathrm{Diameter}})\sqrt{\mbox{Number of Death Stars}} $

There is also a chance that the attacking Death Stars and any other ships in the fleet will be destroyed. The chance of this occurring is:

  • $ \frac{\sqrt{\mathrm{Diameter}}}{2} $

These formulas are taken from the Formula Thread on the Forum.