Using the 2016 Transit of Mercury to Find the Distance to the Sun

Abstract

The May 9, 2016, transit of Mercury was observed simultaneously from the Big Bear Solar Observatory in California and from a site in Germany. From the measured displacement between the views from the two sites of Mercury’s disk silhouetted against the solar granulation, we were able to calculate the distance to the Sun in linear units (kilometers), not merely the proportionality given by Kepler’s third law.