I did indeed factor that in :) [quote]Subtracting the volume of a sphere with a radius of 10km from the volume of the Traveler in order to find the volume of the mantle 5.58×10^12m^3 - 4.19×10^12m^3 = 1.39^12m^3 That’s 1,390,000,000,000m^3 One trillion 390 billion cubic meters.[/quote] I actually weighed the shell, not the innards.