CALCULATING THE VALUE OF THE ASTRONOMICAL UNIT: HOW THE TRANSIT OF MERCURY INDICATES OUR DISTANCE TO THE SUN

Abstract

We present a simplified proposal to determine the Astronomical Unit (AU) through the experimental data obtained from astronomical observation of the transit of Mercury. The data were obtained by the observation activity carried out in a Brazilian school and in cooperation with an international institution. This activity showed that despite the short distance between the two observation sites in relation to planet Earth, the 2019 Mercury transit record made it possible determine the value of the AU with a good approximation.  The transits of planets in orbit closer to the Sun have a certain didactic-pedagogical importance. The activity allows knowing and applying experimental data, developing knowledge such as geometric constructions, trigonometry, ratios and proportions, Kepler’s laws, geographic coordinates and geolocation, concepts that demonstrate that the activity allows interdisciplinarity with students.