Engines of Our Ingenuity

No. 1006:
THE NEPTUNE AFFAIR

by John H. Lienhard

Click here for audio of Episode 1006.

Today, another useless fight over who was first. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

J. Donald Fernie tells the convoluted story of Neptune. It begins in 1841 when John Adams, a brilliant Cambridge student, took an interest in the irregular movement of Uranus. Maybe the irregularity was caused by another, yet undiscovered, planet.

In 1843, Adams went to the Cambridge astronomy professor, James Challis, with a computational scheme. Challis got the data Adams needed from the royal astronomer, George Airy. Adams went to work. Two years later, he knew where to aim a telescope to find the mystery planet. He asked Challis to look for it. Challis didn't want to take on the job. He sent Adams to Airy.

Airy read Adams's work and sent back a note with a minor question. The question struck Adams as too simple. He figured the great Airy was writing rhetorically. He didn't bother to answer. Airy thought the young man was snubbing him. He wrote an angry letter to Challis, and he wouldn't even to speak to Adams.

Months later, a young French astronomer, LeVerrier, made the same calculation Adams had. He also went to Airy. Airy heard him out, then went to Challis and said, "Let's look for the planet." Challis finally began looking. But so did German astronomers. On September 23, 1846, the Berlin Observatory found the planet we call Neptune. It lay very near the spot both young men had predicted.

Airy wrote congratulations to LeVerrier. The French Academy cheered a French triumph and tried to name the planet after LeVerrier instead of naming it after yet another Roman god. Then the great English astronomer, John Herschel, announced that Adams had actually done the calculation first.

The French were furious at Herschel. The English Royal Society was equally furious at Airy and Challis for dropping the ball. They subjected them to a public humiliation from which neither ever fully recovered. And what of Adams and LeVerrier?

Well, those two level-headed young men became close friends. After all, they'd discovered Neptune, hadn't they? This nationalistic stuff wasn't their fight. But then, a few years later, a Harvard astronomer showed that their calculations had been incomplete. They'd both been lucky to find anything at all.

Maybe the crowning irony was the discovery, in 1980, of notes that Galileo had made in 1612 and 1613. He'd clearly identified Neptune, but he hadn't realized it was moving in relation to the stars behind it. He thought it was another star.

So, who did discover Neptune? Well, that's the most misleading kind of scientific question. The next time anyone tells you who was first to discover this or that, be wary. For singular discoverers are only the stuff of myth. They are not what science is really made of.

I'm John Lienhard at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Fernie, J.D., The Neptune Affair. American Scientist, March-April, 1995, pp. 116-119.

See also the Encyclopaedia Britannica entry under "Neptune."


The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

Previous Episode | Search Episodes | Index | Home | Next Episode