Overwhelming scientific consensus and empirical evidence from satellite imagery, orbital flights, and centuries of geophysical data drive the 99.3% market-implied odds against a flat Earth. Traders treat this as settled fact rather than cultural debate, with fringe flat-Earth claims confined to niche online communities and lacking any institutional or mainstream traction. Historical precedents like Eratosthenes’ measurements and modern GPS networks reinforce the dominant narrative, leaving little room for momentum shifts. Realistic upset scenarios remain remote and would require unprecedented discoveries contradicting all known physics and observations, an outcome traders price as negligible given the stability of the evidence base.