Midiendo el cielo y la Tierra

Ancient scientists achieved prodigious feats in obtaining some preliminary estimates of the size of our planet and the distances of the most important stars. Their work stimulated the generations that followed, equipped with better mathematical tools and more precise instruments, who nevertheless faced a difficult logical puzzle: there is a curious symmetry in the measurement of the sky and the Earth. To determine the geographical position, the distance between two locations or even the size of the Earth itself, it was essential to make measurements of the stars, such as finding the height of a star. But that relationship was reciprocal, and estimating the position and distance to the stars was only possible through measurements that had the Earth itself as a measurement standard or knowing in detail the distance between two observation sites. Precision geography was not possible without astronomy, nor vice versa. In this fascinating book we will see how the distances in either of the two systems could be obtained with some simplicity in relative values. However, it took a lot of effort to move to a system of absolute magnitudes that would allow us to access today's complex measurements.