Fair enough, although I bet with a "high-res" enough simulation and physics engine, you could probably account for most of those externalities that would impact

Fair enough, although I bet with a "high-res" enough simulation and physics engine, you could probably account for most of those externalities that would impact the simulation via context clues, like (simplistic examples) crater == asteroid, increased radiation == solar flare, etc. For example, if you took a video of a coin being tossed into a coin pond, and then CGIed the coin out of the video, you could probably hire a criminal forensics-style physicist who could go through the video frame by frame, and then tell you the type of coin, velocity, point of impact, etc. just based on the splash and ripples.