How to prove heliocentrism

http://www2.astro.psu.edu/users/rbc/a1/lec4_f1.jpg

Hold your thumb up at arms length. Look at it with one eye. Then look at it with the other eye. Its position appears to change, with respect to the background. This is called parallax. If the earth moves around the Sun, then the apparent positions of the stars must change between January and June. (Even if all the stars are at the same distance, as if drawn on a wall, their positions with respect to one other must change as you get closer and farther away from one side.)

http://www2.astro.psu.edu/users/rbc/a1/lec4n.html