Today in Science History – January 21 – John Couch Adams and the Discovery of Neptune

Neptune as seen from Voyager 2. Credit: NASA

January 21 marks the passing of John Couch Adams. John Couch Adams was the astronomer famous for almost being the first to discover the planet Neptune.

In 1845, astronomers were interested in the orbit of the planet Uranus. It had recently completed a complete revolution around the Sun since it was discovered in 1781. The orbit of Uranus showed signs of some other large mass was affecting Uranus’ orbit. Perhaps a mass large enough to be another planet. Adams set himself to find that planet.

Unfortunately for Adams, French mathematician Urbain Le Verrier also started looking for a solution to the problem of the missing planet. Both men found solutions and presented their results. Adams presented his results to the astronomers at Cambridge Observatory where they were basically ignored. That is until Le Verrier publicly announced the results calculations in Paris to the Académie des Sciences where it was largely ignored as well.

Upon hearing of Le Verrier’s work, Astronomer Royal George Airy remembered Adams’ calculations and began a frantic search for the new planet. In the meantime, Le Verrier sent his calculations to Berlin where Johann Gottfried Galle quickly found Neptune within 1° of the calculated position. After the discovery was announced, the British astronomers discovered they had spotted the planet earlier on two separate observations, but failed to recognize their achievement.

In general, discovery is credited to both John Couch Adams and Urbain Le Verrier. Adams’ calculations were completed earlier than Le Verrier’s, but Le Verrier’s results were published earlier and the final solution was closer to the actual location of Neptune.

Notable Science History Events for January 21

1926 – Camillo Golgi died.

Camillo Golgi
Camillo Golgi (1843 – 1926)

Golgi was an Italian cytologist who shares the 1906 Nobel Prize in Medicine for his research into the nervous system. He discovered that if you used silver compounds to stain microscope slides of nerve tissue, new and unseen structures could be seen. This technique also showed the individual neurons in the brain.

1912 – Konrad Emil Bloch was born.

Bloch was a German-American biochemist who shared the 1964 Nobel Prize in Medicine with Feodor Lynen for their discoveries concerning the biosynthesis of fatty acids and cholesterol. Bloch discovered that acetic acid was a major contributor to the natural formation of cholesterol. Both men discovered how the body creates and regulates fatty acids and cholesterol.

1892 – John Couch Adams died.

1847 – Joseph-Achille Le Bel was born.

Joseph Achille Le Bel
Joseph-Achille Le Bel (1847 – 1930). 

Le Bel was a French chemist who was a co-founder of the study of stereochemistry. He was investigating the polarization of light when reflected off of organic compounds. He theorized a molecule in which four different atoms or groups were linked to a carbon atom could exist as mirror images of each other. He published his theory independently of Jacobus van’t Hoff, who was also working on stereochemical molecules.