The Discovery of Ceres

In 1796, an an astronomical conference, the astronomy community decided that a systematic search should be undertaken for other planets.

In 1800, six German astronomers, the so-called "celestial police," decided to put the Titius-Bode law to the test by looking for the "missing planet" at 2.8 AU.  But they were scooped.

On January 1, 1801, Giuseppe Piazzi, a Sicilian monk, announced the discovery of an unknown body in the heavens.  He discovered this object during routine observations of stars he was making.  He was not searching for new or unknown objects. He named the object "Ceres" (from the Roman goddess of the harvest; hence "cereal").  Piazza at first thought it was a comet. He observed it for 41 days.

In 1801, Gauss figured out how to take a few observations, such as those made by Piazza,  and calculate an entire orbit to predict the future positions of an object.  Using Gauss' new mathematical tools, Ceres was re-found on December 7, 1801 (in another great triumph for mathematical physics).  And what is the answer? Ceres is located at a = 2.77 AU.

 Planet number Add 4 Divide by 10 Actual a (AU) Planet? 0 4 0.4 0.39 Mercury 3 7 0.7 0.72 Venus 6 10 1.0 1.00 Earth 12 16 1.6 1.52 Mars 24 28 2.8 2.77 Ceres 48 52 5.2 5.2 Jupiter 96 100 10.0 9.56 Saturn 192 196 19.6 19.22 Uranus 384 388 38.8 ... ... 768 772 77.2 ... ...

Now the Titius-Bode law is looking very strong, indeed!

... the discovery of the  asteroid belt