Jeremiah Horrocks
Jeremiah Horrocks was born at Lower Lodge Farm in Toxteth Park, a former royal deer park near Liverpool, Lancashire. His father James had moved to Toxteth Park to be apprenticed to Thomas Aspinwall, a watchmaker. Subsequently James married his master's daughter Mary. Both families were well educated Puritans who held unorthodox beliefs for their time. The Puritans were excluded from public office by the early 1600s. This exclusion pushed them towards other callings like watchmaking and astronomy. By 1600 the Aspinwalls had become a successful family of watchmakers. Jeremiah was introduced early to astronomy through boyhood chores. He measured local noon used to set local clocks. His Puritan upbringing instilled an enduring suspicion of astrology, witchcraft and magic.
In 1632 Horrocks matriculated at Emmanuel College at the University of Cambridge as a sizar. At Cambridge he associated with the mathematician John Wallis and the platonist John Worthington. That time he was one of only a few at Cambridge to accept Copernicus's revolutionary heliocentric theory. He studied the works of Johannes Kepler and Tycho Brahe among others. In 1635 Horrocks left Cambridge without graduating for reasons not clear. Marston suggests that he may have needed to defer extra costs until employed. Aughton speculates that he failed exams due to concentrating too much on his own interests. Another possibility is that he did not want to take Anglican orders so a degree held limited use to him.
Now committed to the study of astronomy Horrocks began to collect astronomical books and equipment. By 1638 he owned the best telescope he could find. Liverpool was a seafaring town where navigational instruments like the astrolabe were easy to find. There was no market for very specialised astronomical instruments he needed. His only option was to make his own. His father and uncles were watchmakers with expertise in creating precise instruments. Apparently he helped with the family business by day. The watchmakers in his family supported his vocation by assisting in design and construction of instruments to study stars at night. Horrocks owned a three-foot radius astronomicus but reached its limitations by January 1637. He built a larger and higher precision version himself.
Horrocks was the first to demonstrate that the Moon moved in an elliptical path around the Earth. He posited that comets followed elliptical orbits as well. He supported his theories by analogy to motions of a conical pendulum. A plumb bob drawn back and released followed an elliptical path. Its major axis rotated in direction of revolution just as apsides of the Moon's orbit did. He anticipated Isaac Newton in suggesting influence of Sun as well as Earth on Moon's orbit. In final months of life Horrocks made detailed studies of tides. He attempted to explain nature of lunar causation of tidal movements. Newton acknowledged Horrocks's work in relation to theory of lunar motion later.
Johannes Kepler had published Rudolphine Tables in 1627. Two years later he published extracts including warning concerning transit of Mercury in 1631. Horrocks's own observations combined with friend William Crabtree convinced him Kepler's tables needed correction. Kepler predicted near-miss of transit of Venus in 1639 but Horrocks predicted it would occur. Horrocks made simple helioscope by focusing image of Sun through telescope onto plane surface. From Much Hoole location he calculated transit would begin at approximately 3:00 pm on the 24th of November 1639 Julian calendar. Weather was cloudy but he first observed tiny black shadow of Venus crossing Sun at about 3:15 pm. He continued observation for half hour until Sun set. The 1639 transit was also observed by William Crabtree from Broughton near Manchester.
Horrocks returned to Toxteth Park sometime in mid-1640 and died suddenly from unknown causes on the 3rd of January 1641. He was age 22 when death occurred. As expressed by Crabtree the loss was incalculable. It is believed that Horrocks was buried at Toxteth Unitarian Chapel though no proof exists. His treatise on transit Venus in sole visa nearly caused loss to science due to chaos of English Civil War. The manuscript survived only because of this specific historical context. Chaos of war threatened to destroy his work entirely before publication could happen.
Horrocks is remembered on plaque in Westminster Abbey and lunar crater named after him. In 1859 marble tablet and stained-glass windows commemorating him were installed in Parish Church of St Michael Much Hoole. Toxteth Unitarian Chapel contains memorial plaque commemorating achievements. Horrocks Avenue in Garston Liverpool is also named after him. In 1927 Jeremiah Horrocks Observatory built at Moor Park Preston. In 2011 sculpture by Andy Plant titled Heaven and Earth installed at Pier Head in Liverpool. Sculpture consists of telescope looking at working orrery with planet Venus replaced by figure of astronomer depicted as angel. In 2023 new play Horrox staged in Cambridge's ADC Theatre from the 28th of March to the 1st of April.
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Common questions
Where was Jeremiah Horrocks born and what was his family background?
Jeremiah Horrocks was born at Lower Lodge Farm in Toxteth Park near Liverpool, Lancashire. His father James worked as a watchmaker and married the daughter of his master Thomas Aspinwall. Both families were well educated Puritans who held unorthodox beliefs for their time.
When did Jeremiah Horrocks die and how old was he when he passed away?
Jeremiah Horrocks died suddenly from unknown causes on the 3rd of January 1641. He was age 22 when death occurred. He returned to Toxteth Park sometime in mid-1640 before his sudden passing.
What astronomical discovery did Jeremiah Horrocks make about the Moon's movement?
Jeremiah Horrocks was the first to demonstrate that the Moon moved in an elliptical path around the Earth. He posited that comets followed elliptical orbits as well. He anticipated Isaac Newton in suggesting influence of Sun as well as Earth on Moon's orbit.
How did Jeremiah Horrocks predict the transit of Venus in 1639?
Horrocks made simple helioscope by focusing image of Sun through telescope onto plane surface. From Much Hoole location he calculated transit would begin at approximately 3:00 pm on the 24th of November 1639 Julian calendar. Weather was cloudy but he first observed tiny black shadow of Venus crossing Sun at about 3:15 pm.
Where is Jeremiah Horrocks commemorated today and what memorials exist for him?
Horrocks is remembered on plaque in Westminster Abbey and lunar crater named after him. In 1859 marble tablet and stained-glass windows commemorating him were installed in Parish Church of St Michael Much Hoole. Toxteth Unitarian Chapel contains memorial plaque commemorating achievements.