sentences:  The "Astronomical Almanach Online" as of 2016 recommends a standard uncertainty of for Earth mass, 
  
  Earth's mass is variable, subject to both gain and loss due to the accretion of in-falling material, including micrometeorites and cosmic dust and the loss of hydrogen and helium gas, respectively.The combined effect is a net loss of material, estimated at per year.This amount is of the total earth mass.