A desert is a landscape or region that receives an extremely low
amount of precipitation, less than enough to support growth of
most plants. Most deserts have an average annual precipitation
of less than 400 millimetres. Deserts can also be described as
areas where more water is lost by evapotranspiration than falls
as precipitation. Celestia has several regions of desert that
were created by orbital bombardment and actually get more water
than the above suggests, but cannot support plant life making
them look the same. Celestia is actually a very temperate world
and had relatively few natural deserts.