While some may observe that they think they see too far, or the horizon looks flat while someone tells them it's flat, so the earth must be flat, I see a sun set below the horizon without shrinking in size & fading away as if becoming more distant. I see a moon lit from the same direction as where the sun went, underground so it would appear. I know that if as I observe this last night I were to call someone on the other side of world in China, they would tell me the sun is up.
Trust your eyes.