Jeremiah Horrocks

Jeremiah Horrocks (1618 – 3 January 1641), sometimes given as Jeremiah Horrox (the Latinised version that he used on the Emmanuel College register and in his Latin manuscripts),[1] was an English astronomer who was the only person to predict, and one of only two people to observe and record, the transit of Venus of 1639, which was the first transit of Venus to be predicted and observed.

Life and work

Horrocks was born in Lower Lodge, in Toxteth Park, Liverpool, Merseyside. His father was a small farmer; his uncle was a watchmaker; he was relatively poor during his entire brief life. He joined Emmanuel College on 11 May 1632 and matriculated as a member of the University of Cambridge on 5 July 1632 as a sizar. In 1635 he left without formally graduating, presumably due to the cost of continuing his studies.[2] The traditional view is that he supported himself financially by holding a curacy in Much Hoole, near Preston in Lancashire, but there is little evidence for this. According to local tradition in Much Hoole, he lived at Carr House, within the Bank Hall Estate, Bretherton. Carr House was a substantial property owned by the Stones family who were prosperous farmers and merchants, and Horrocks was a tutor for the Stones children.[3] He may have been a Calvinist and, through his connection with Emmanuel College, a Puritan, although there is little evidence of his religious convictions.[4]

At Cambridge, he became familiar with the works of Johannes Kepler, Tycho Brahe, and others. Horrocks read most of the astronomical treatises of his day, found the weaknesses in them and was suggesting new lines of research by the age of seventeen. He was the first to demonstrate that the Moon moved in an elliptical path around the Earth, he wrote a treatise on Keplerian astronomy and began to explore mathematically the properties of the force that later became known as gravity. Isaac Newton in the Principia[5] acknowledged Horrocks's work in relation to the theory of the Moon. Horrocks has also been described as a bridge which connected Newton with Copernicus, Galileo, Brahe and Kepler.[6]
Transit of Venus
Observation of 1639 transit of Venus in Venus in sole visa by Jeremiah Horrocks, published in 1662 by Johannes Hevelius

Horrocks was convinced that Lansberg's tables were inaccurate when Kepler predicted that a near-miss of a transit of Venus would occur in 1639. Horrocks believed that the transit would indeed occur, having made his own observations of Venus for years.

Horrocks focused the image of the Sun through a simple telescope onto a piece of card, (see helioscope) where the image could be safely observed. From his location in Much Hoole, he calculated that the transit was to begin at approximately 3:00 pm on 24 November 1639 (Julian calendar, or 4 December in the Gregorian calendar). The weather was cloudy, but he first observed the tiny black shadow of Venus crossing the Sun on the card at about 3:15 pm, and observed for half an hour until sunset. The 1639 transit was also observed by his friend and correspondent, William Crabtree, from his home in Broughton, near Manchester.

Horrocks' observations allowed him to make a well-informed guess as to the size of Venus (previously thought to be larger and closer to Earth), as well as to make an estimate of the distance between the Earth and the Sun. His figure of 95 million kilometres (59 million miles, 0.63 AU) was far from the 150 million kilometers (93 million miles) that it is known to be today but it was a more accurate figure than any suggested up to that time.

A treatise by Horrocks, Venus in sole visa (Venus in transit across the Sun) was published by Johannes Hevelius at his own expense in 1662. This paper, which caused great excitement when revealed to members of the Royal Society 20 years after it was written, contained much evidence of Horrocks' enthusiastic and romantic nature, including humorous comments and passages of original poetry. When speaking of the century separating Venusian transits, he rhapsodised,

" ...Thy return
Posterity shall witness; years must roll
Away, but then at length the splendid sight
Again shall greet our distant children's eyes."

Lunar Activity

Horrocks also put his energies into the highly complex task of determining the Moon's orbit. He correctly hypothesised that the orbit was elliptical rather than circular, and he anticipated Isaac Newton in suggesting an influence on the orbit from the sun as well as the earth. In the final months of his life he also made detailed study of tides, in an attempt to explain the nature of lunar causation of tidal movements.
Death and remembrance
Jeremiah Horrocks Observatory on Moor Park, Preston

Horrocks returned to Toxteth Park sometime in the summer of 1640 and died suddenly and from unknown causes on 3 January 1641, aged only 22. As expressed by Crabtree, "What an incalculable loss!"[7]

Horrocks is remembered on a plaque in Westminster Abbey and the lunar crater Horrocks is named after him. In 1859 a marble tablet and stained-glass windows commemorating him were installed in The Parish Church of St Michael, Much Hoole.[3] Horrocks Avenue, in Garston[disambiguation needed ], Liverpool, is named after him.

In 1927, the Jeremiah Horrocks Observatory was built on Moor Park, Preston and named after Horrocks.
Jeremiah Horrocks Institute

The Jeremiah Horrocks Institute for Astrophysics and Supercomputing, was established in 1993 at the University of Central Lancashire.[8]
References

^ Marston, Paul (2007). "History of Jeremiah Horrocks". Retrieved 2007-12-08. - See footnote 1
^ Venn, J.; Venn, J. A., eds. (1922–1958). "Horrox, Jeremiah". Alumni Cantabrigienses (10 vols) (online ed.). Cambridge University Press.
^ a b http://www.lancashirepioneers.com/horrocks/images.asp
^ Westfall, Richard S. (1995). "Jeremiah Horrocks; The Galileo Project". Retrieved 2007-12-08.
^ Isaac Newton, 'Principia', Book 3, Proposition 35, Scholium.
^ Chapman, Allan (1994). "Jeremiah Horrocks: His Origins and Education". Archived from the original on 2007-10-15. Retrieved 2007-11-19.
^ Opera Posthuma of Jeremiah Horrocks, ed. John Wallis, London, 1672.
^ "About the Jeremiah Horrocks Institute", University of Central Lancashire

Further reading

Applebaum, W.; Hatch; Hatch, R. A. (1983). "Boulliau Mercator and Horrocks Venus in Sole Visa - Three Unpublished Letters". Journal for the History of Astronomy 14 (3): 166–179. Bibcode 1983JHA....14..166A.
Aughton, Peter (2004). The Transit of Venus: The Brief, Brilliant Life of Jeremiah Horrocks, Father of British Astronomy. London: Weidenfeld & Nicolson. ISBN 0-297-84721-X.
Chapman, Allan (1990). "Jeremiah Horrocks, the transit of Venus, and the 'New Astronomy' in early seventeenth-century England". Quarterly Journal of the Royal Astronomical Society 31: 333–357. Bibcode 1990QJRAS..31..333C.
Chapman, Allan (2004). "Transit of Venus: Horrocks, Crabtree and the 1639 transit of Venus". Astronomy & Geophysics 45 (5): 5–31. Bibcode 2004A&G....45e..26C. doi:10.1046/j.1468-4004.2003.45526.x.
Hughes, David W. (2005). "Horrocks's bogus law". Astronomy & Geophysics 46 (1): 14–16. Bibcode 2005A&G....46a..14H. doi:10.1046/j.1468-4004.2003.46114.x.
Maor, Eli (2000). Venus in Transit. Princeton: Princeton University Press. ISBN 0-691-11589-3.
Sheehan, William; Westfall, John (2004). The Transits of Venus. Amherst, New York: Prometheus Books. ISBN 1-59102-175-8.
Whatton, Arundell Blount (1875). Memoir of the Life and Labors of the Rev. Jeremiah Horrox. London: William Hunt and Company.

External links

Chasing Venus, Observing the Transits of Venus Smithsonian Institution Libraries
BBC report: Celebrating Horrocks' half hour
Horrocks memorial in Westminster Abbey
O'Connor, John J.; Robertson, Edmund F., "Jeremiah Horrocks", MacTutor History of Mathematics archive, University of St Andrews.
Jeremiah Horrocks Institute