Algodoo

If Earth was an infinite plane, extending in all directions with no end, gravity would act evenly, all in the same direction in any position, no matter how far away it is. Because of this, and the fact that Light bends with gravity, light would curve down into the ground (Shown by these laser beams), a side effect of this is that a far away point could be seen somewhere in the sky, since we see things as if light took a perfectly straight path from us to that point. So an infinite Earth would feel like the inside of an infinite hollow Earth.