Jacques Cassini was a French astronomer and geodesist born on June 18, 1677. He was the son of the famous astronomer Gian Domenico Cassini and made significant contributions to the field of astronomy, particularly in the study of planetary motion and the measurement of the Earth’s shape. Cassini is best known for his work on the Cassini Division, a gap in the rings of Saturn. He also played a crucial role in the development of geodesy, the science of measuring the Earth's geometric shape, orientation in space, and gravity field, which laid the groundwork for modern surveying techniques.