Engines of Our Ingenuity

No. 2222:
JEREMIAH HORROCKS

by John H. Lienhard

Today, a planetary prodigy. 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.

Jeremiah Horrocks got a new telescope in 1638. That was thirty years after the Dutch had made the first telescope. Horrocks was twenty, and had already been doing astronomy with a more primitive instrument. Now he had a good one and was about to earn his name as the Father of British Astronomy. The catch is, he would also die three years later at the age of only 23.

Like another astronomer, Omar Khayyam, Horrocks was also a poet. And he used poetry to sing his telescope's praises:

Divine the hand which to Urania's power
Triumphant raised the trophy, which on man
Hath first bestowed the wondrous tube by art
Invented, and in noble daring taught
His mortal eyes to scan the furthest heavens.

By then, Horrocks knew Kepler's and Copernicus's work intimately. Galileo had only recently finished his Dialogue Concerning the Two Chief World Systems and Horrocks probably had yet to read it.

He was born and would die near Liverpool. He'd studied for a few years at Cambridge, but, at seventeen, came home to study astronomy. England was then far from the intellectual centers of Europe, and he had little access to the leading science of the day.

Horrocks's first triumph with his new telescope came a year later. He'd predicted the orbit of Venus. Now he and a friend set out to verify it. They made the first observation of the transit of Venus -- its passage across the face of the sun. To do that, they had to let the telescope project its view on a screen in a darkened room.

Horrocks's religious leanings were Puritan and intense. But he had no trouble opposing Catholic teachings about a Ptolemaic Earth-centered universe. His poetry about it was scathing:

Why should'st thou try, O Ptolemy, to pass
Thy narrow-bounded world for aught divine?

And so he gained an amazing understanding of the solar system. He calculated that the sun is sixty million miles from Earth. That offended other astronomers who thought it was much closer. We now know that it's still further -- over ninety million miles away. He formed a rudimentary concept of gravitational forces. He understood that comet orbits are elliptical. Horricks's Law said that all the then-known planets would appear the same size, if viewed from the sun. Not true for Mars or Saturn; but otherwise very accurate.

So history leaves its what-if questions: What might Mozart or Schubert have written at the age of sixty? What if Evariste Galois, who set the foundations of modern algebra, had lived beyond the age of nineteen? Would Jeremiah Horrocks have eclipsed Newton who followed, two generations later? That question obviously touched Horrocks's 19th-century biographer A. B. Whatton, who left his own florid lines of Victorian verse:

That meteor-life, soon lost to vision here,
Now shines unclouded in a glorious sphere;
Yet here its light his bright example gives,
And here in fame undying Horrox lives.

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

(Theme music)


W. Applebaum, Horrocks, Jeremiah. Dictionary of Scientific Biography, C.C. Gilespie, ed. Vol. VI (New York: Charles Scribner's Sons, 1972): pp. 514-516.

P. Aughton, The Transit of Venus: The Brief, Brilliant Life of Jeremiah Horrocks, Father of British Astronomy. (London: Weidenfeld & Nicolson, 2004).

See also: http://en.wikipedia.org/wiki/Jeremiah_Horrocks

Jeremiah Horrocks
An imagined image of Horrocks observing the transit of Venus
(Public domain, courtesy of Wikipedia)


The Engines of Our Ingenuity is Copyright © 1988-2006 by John H. Lienhard.