The Inverse Square Law (testable, observable, measurable and repeatable) proves that when you double the distance to a light source, you'll only get a quarter of its irradiance.
How far away is the sun?
North at the center. South is all around us:
The sun, moon, wandering stars and zodiacs rotate right above our heads if we live on a "flat, non-rotating earth", just as NASA has documented.
The sun, moon, wandering stars and zodiacs circle right above our heads:
If our sun was 93 Million miles away, it would be impossible to see it. Mathematics and the scientific method proves that our sun is just outside the firmament.