The fact that it says it's a ball that "you must carry" makes me think it's talking about how one "carries" guilt. In my opinion, it's a metaphor. Really cool experiment though, and your methodology seems solid. It's just too bad we'll most likely never get a clear answer. Also, with a mass that, well, massive I'd think there'd be some serious gravitational disturbances, tidal changes, even a shift in earth's orbit. Interesting stuff.