Resolves once I have the opportunity to view the Earth from space and can confirm the answer directly with my own eyes.

I'll require that we be in orbit or otherwise going "around" the Earth so that I can confirm it's actually a ball and not just a circle. Upper atmosphere or a brief suborbital trajectory is not conclusive. I need to be able to see the continents changing as my perspective changes.

I'll do my best to ensure that I'm looking through a real window and it couldn't secretly be a TV screen.