The flat earth and heliocentric models are opposites in almost every way. Is it really that hard to tell which is correct?
The answer is NO. The earth is a sphere. It's obvious by the apparent positions of the celestial objects in the sky as observed from earth. By simple observation you can determine conclusively that the earth is round and that a flat earth is impossible.

One of the simplest examples illustrating this is Polaris. See why here:

http://debunkingflatearth.blogspot.com/2016/02/debunking-flat-earth-how-polaris-proves.html