In the space of two centuries, the works of Nicolaus Copernicus (1473–1543), Giordano Bruno (1548–1600), Galileo Galilei (1564–1642), and Johannes Kepler (1571–1630) revolutionized our view of the universe, postulating that planets, including the Earth, move around the Sun, eliminating the role of our planet.
But many questions remained mysterious regarding the existence and behavior of the planets known at the time: Mercury, Venus, Earth, Mars, Jupiter and Saturn. In this even the most brilliant astronomers have made missteps, as is often the case with those working on the frontier of knowledge.
Kepler believed that the existence of five planets, in addition to Earth, would be linked to the fact that there are exactly five Platonic solids: tetrahedron, cube, icosahedron, dodecahedron and icosahedron. The discovery of Uranus by William Herschel (1738–1822) in 1781 dealt a death blow to this beautiful Keplerian model.
Another controversial idea was proposed by the Germans Johan Titius (1729–1796) and Johann Bode (1747–1826): the radii of the orbits of the planets would be in the same proportion as a certain sequence of numbers given by a precise mathematical rule: 0.4 ( Mercury), 0.7 (Venus), 1.0 (Earth), 1.6 (Mars), 2.8 (??), 5.2 (Jupiter) and 10.0 (Saturn).
The approximation is quite good, even for the planet Uranus, which would only be discovered later. But to validate the Titius-Bode law, it would be necessary to find a planet between Mars and Jupiter with an orbit 2.8 times greater than that of Earth. A group of 24 renowned astronomers, called the Celestial Police, was created to search for such a planet.
On January 1, 1801, the Italian Giuseppe Piazzi (1746–1826) observed a moving celestial body that he thought was “something better than a comet”, and which he named after the goddess Ceres. When astronomers lost the position of the star, the situation was saved by the great Carl Friedrich Gauss (1777–1855), aged only 24, who developed a precise method of calculating the trajectory to find Ceres in the sky.
Ceres’ orbit was very close to the Titius–Bode prediction, but the new star was too small to be taken seriously as a planet. It was called an asteroid and is currently considered a dwarf planet. With the discovery of Neptune, the Titius-Bode law was discredited, and is currently considered just a coincidence with no scientific basis.
