GREEN CARDAMOMS by Gaurangi Maitra
SEPTEMBER 23, 2013 will mark the anniversary of the discovery of Neptune in 1846. On July 10, 2011, The Hindu carried the news “Neptune completes first revolution of the sun”, so Neptune had reached the same position as when it was discovered having completed one 165 year orbit. The Hubble space telescope was close enough to take photographs of this event and record the 14th moon of the other blue planet in our solar system.
Neptune is advertised as the first planet virtually discovered by calculation before telescopes could confirm its presence in real time! This statement camouflages the fact that the very process of calculation set its discovery back by almost by 25 years! Anders Johan Lexell studied the orbit of Uranus in its year of discovery (1781). The strange irregularities he found meant either Newton’s gravitation theory was wrong or there was an undiscovered planet causing this disturbance. Calculations from three French scientists working on the Perturbation Theory supported the latter.
Contrary to what we might imagine the probability of locating a new planet was not the next big event for the 19th century scientific community. Various disjointed efforts from 1781 onwards lead to very little actual progress. Therefore in true bureaucratic style, the irregularity was still being duly “noted” in the 1832 proceedings of the British Association for Science and by George Biddell Airy, the royal astronomer at the Greenwich Laboratory. Again characteristically, the proceedings gathered dust for nearly a decade till a student John Cough Adams rediscovered them, understood their significance and completed calculations in 1843.
Now strange and inexplicable events happened; Adams took his completed calculations back and forth between the heads of Cambridge and Greenwich Observatory, predicted the position of the invisible planet in the night sky of September 30, 1845 but strangely did not publish a single paper. At the same time in France, Urbain JJ Le Verrier worked independently and presented a second paper on June 1, 1846 on his calculations. This finally forced Airy to admit (having excavated Adam’s calculations) that both had arrived at the same result! Inexplicably even at this point Airy did not mobilize the relevant British astronomical soft and hardware to the task on a war footing!
Yet, “All of Southampton was abuzz with the latest tantalizing gossip: a new planet, still unseen was travelling around the sun beyond the orbit of Uranus,” writes Laura J Snyder in her unputdownable book The Philosophical Breakfast Club. Not that the French were any better, so when no French observatory took up the search even after his third paper, Verrier sent his results to Johann Gottfried Galle at the Berlin Observatory which had the state of art 9-inch Fraunhofer refractor telescope.
For a search that began 65 years ago in 1781, the curtains came down on the final act in one day. Verrier’s results reached on September 23 and after a short 60-minute search, that very night it was found less than a degree away from his predicted position. This discovery confirmed both gravitational and perturbation theories and extended the known solar system to approximately 4.5 billion km, the average distance of Neptune from the sun. For the final act on Earth, Nicholas Kollerstrom’s “John Herschel on the Discovery of Neptune” is in some ways a scathing indictment. The great men of the Royal Astronomical Society in Britain bickered bitterly, unable to accept that the French had won. They did not accept their own inept handling of this race but stopped the award of its gold medal in a year when new planet had been discovered! Fortunately, the older (and wiser?) Royal Society awarded its Copley Medal to Verrier in 1846.
Nationality before merit? The Trobairitz would be delighted to hear from you at [email protected].