Comparing Measurements of Sun-Earth Distance: Shadow Method and Two Pinhole Method Variations

Abstract

This study compares three methods, one using a newly derived formula (the shadow method) and two conventionally used (the plate pinhole method and tube pinhole method), regarding their accuracy in calculating the distance between the Earth and the Sun. In doing so, the new formula will add to the existing knowledge surrounding viable methods to calculate the distance between the Earth and Sun, focusing primarily on providing insight on methods to make astronomical observation more accessible to the casual observer. The tube and plate pinhole methods were chosen due to their promotion by reputable organizations and use in schools, to best compare to and evaluate the utility of the shadow method in everyday use. Our hypothesis was that the shadow method would have the greatest mean accuracy, followed by the tube pinhole method, and finally the plate pinhole method. Measurements of the shadow and pinhole methods were each carried out multiple times over a day, and the values were inputted into each method’s formula to calculate the estimated Sun-Earth distance and error. Our results validate the hypothesis; however, further investigation would be helpful in determining effective mitigation of each method’s limitations and the effectiveness of each method in determining the distance of other light-emitting objects distant from the Earth.