Astute readers may recognise the title of this posting comes from a book that was written by Professor James Moriarty, mentioned by Sherlock Holmes in “The Valley of Fear”.
Holmes says “Is he not the celebrated author of The Dynamics of an Asteroid, a book which ascends to such rarefied heights of pure mathematics that it is said that there was no man in the scientific press capable of criticizing it?”
It is not known which asteroid Sir Arthur Conan Doyle had in mind, but it is probably he was thinking about Ceres and the mathematician Gauss. For in 1821, Carl Friedrich Gauss wrote a ground-breaking treatise on the dynamics of an asteroid.
On January 1, 1801, the Italian astronomer Giuseppe Piazzi discovered a planetoid, working from an observatory in Palermo, Italy. This object, which he christened Ceres, was moving in the constellation Taurus. It was named after the Roman goddess of agriculture, grain crops, fertility and motherly relationships.
It was observed for 41 days, after which it was lost to sight when its light vanished in the rays of the sun, and the astronomers could no longer find it. There was now a challenge of calculating Ceres' orbit using only the observations Piazzi made, so that astronomers would be able to sight Ceres when it reemerged.
The French astrophysicist, Pierre-Simon Laplace (1749-1827), declared that it simply could not be done.
But already, the 24 year old German mathematician Carl Friedrich Gauss had considered that this type of problem – to determine a planet's orbit from a limited handful of observations – "commended itself to mathematicians by its difficulty and elegance."
Gauss discovered a method for computing the planet's orbit using only three of the original observations and successfully predicted where Ceres might be found – “... for it is now clearly shown that the orbit of a heavenly body may be determined quite nearly from good observations embracing only a few days; and this without any hypothetical assumption."
The prediction catapulted him to worldwide acclaim, due, in the words of biographer W. K. Bühler, "to the popular appeal which astronomy has always enjoyed," and launched one of the most fruitful careers in the history of science.
NASA's Dawn mission has now sent back the best-ever view of this asteroid, which lies in the asteroid belt between Mars and Jupiter. The spacecraft is just 147,000 miles and a few months short of reaching Ceres, which the largest unexplored rock between the Sun and Pluto.
“Ceres is a ‘planet’ that you’ve probably never heard of,” said Robert Mase, Dawn project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “We’re excited to learn all about it with Dawn and share our discoveries with the world.”
Originally classified as a planet, Ceres was later categorized as an asteroid and then reclassified as a dwarf planet in 2006.