MillionMilesAway
Well-Known Member
You're right on one point anyway. If nothing comes from outside then it always weighs the same. 1 + 0 = 1. I'd be unsure on whether the energy input from the sun all gets used or whether any of it is converted to mass though, that could increase weight.
You can't make mass from energy.
The sun's energy is important in converting mass from one object into another object (e.g. plant growth).