Coreolis effect, celestial seasons, moon phases, the fact that we can accurately predict comets and meteors' arrivals, temperature variation, historical text, the lack of scientific authority flat earth conceptualizers have, gravity, shadows, the atmosphere, centripetal force, the observation about telescopes showing all others celestial bodies as generally spherical.
we need to multiply the per-voxel cost by 4/3
Because your blade is made of atoms and the bond strength is nowhere near strong enough in it to surpass the weak nuclear force.