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.