Jeremiah Horrocks
Encyclopedia
Jeremiah Horrocks sometimes given as Jeremiah Horrox (the Latinised version that he used on the Emmanuel College register and in his Latin manuscripts), 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.
; 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. 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. He may have been a Calvinist and, through his connection with Emmanuel College, a Puritan
, although there is little evidence of his religious convictions.
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
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.
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
.
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 59 million miles (95 million kilometres, 0.63 AU
) was far from the 93 million miles (150 million kilometers) 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,
. 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.
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.
Horrocks Avenue, in Garston
, Liverpool, is named after him.
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
who was the only person to predict, and one of only two people to observe and record, the transit of Venus
Transit of Venus
A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth, becoming visible against the solar disk. During a transit, Venus can be seen from Earth as a small black disk moving across the face of the Sun...
of 1639.
Life and work
Horrocks was born in Lower Lodge, in Toxteth Park, Liverpool, Merseyside. His father was a small farmerFarmer
A farmer is a person engaged in agriculture, who raises living organisms for food or raw materials, generally including livestock husbandry and growing crops, such as produce and grain...
; his uncle was a watchmaker
Watchmaker
A watchmaker is an artisan who makes and repairs watches. Since virtually all watches are now factory made, most modern watchmakers solely repair watches. However, originally they were master craftsmen who built watches, including all their parts, by hand...
; he was relatively poor during his entire brief life. He joined Emmanuel College
Emmanuel College, Cambridge
Emmanuel College is a constituent college of the University of Cambridge.The college was founded in 1584 by Sir Walter Mildmay on the site of a Dominican friary...
on 11 May 1632 and matriculated
Matriculation
Matriculation, in the broadest sense, means to be registered or added to a list, from the Latin matricula – little list. In Scottish heraldry, for instance, a matriculation is a registration of armorial bearings...
as a member of the University of Cambridge
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
on 5 July 1632 as a sizar
Sizar
At Trinity College, Dublin and the University of Cambridge, a sizar is a student who receives some form of assistance such as meals, lower fees or lodging during his or her period of study, in some cases in return for doing a defined job....
. In 1635 he left without formally graduating, presumably due to the cost of continuing his studies. The traditional view is that he supported himself financially by holding a curacy
Curate
A curate is a person who is invested with the care or cure of souls of a parish. In this sense "curate" correctly means a parish priest but in English-speaking countries a curate is an assistant to the parish priest...
in Much Hoole
Much Hoole
Much Hoole is a village and civil parish in the borough of South Ribble, Lancashire, England. The parish of Much Hoole had a population of 1,851 at the time of the 2001 census.-History:...
, near Preston in Lancashire, but there is little evidence for this. According to local tradition in Much Hoole, he lived at Carr House
Carr House
Carr House, is situated within the Bank Hall Estate, half-way between the villages of Tarleton and Much Hoole at the extreme north-west of the village of Bretherton, Lancashire...
, within the Bank Hall
Bank Hall
Bank Hall is a Jacobean mansion south of the village of Bretherton in Lancashire, England. It is a Grade II* Listed Building. The hall was built on the site of a previous building in 1608 during the reign of James I by the Banastre family who were Lords of the Manor. It was extended during the 18th...
Estate, Bretherton
Bretherton
Bretherton is a small village and civil parish in the Borough of Chorley, Lancashire, England situated to the south west of Leyland and east of Tarleton. Its name suggests pre-conquest origins and its early history was closely involved with the manor house Bank Hall and the families who lived there...
. 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. He may have been a Calvinist and, through his connection with Emmanuel College, a Puritan
Puritan
The Puritans were a significant grouping of English Protestants in the 16th and 17th centuries. Puritanism in this sense was founded by some Marian exiles from the clergy shortly after the accession of Elizabeth I of England in 1558, as an activist movement within the Church of England...
, although there is little evidence of his religious convictions.
At Cambridge, he became familiar with the works of Johannes Kepler
Johannes Kepler
Johannes Kepler was a German mathematician, astronomer and astrologer. A key figure in the 17th century scientific revolution, he is best known for his eponymous laws of planetary motion, codified by later astronomers, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican...
, Tycho Brahe
Tycho Brahe
Tycho Brahe , born Tyge Ottesen Brahe, was a Danish nobleman known for his accurate and comprehensive astronomical and planetary observations...
, 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
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
moved in an elliptical path around the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
, 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
Isaac Newton
Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...
in the Principia
Philosophiae Naturalis Principia Mathematica
Philosophiæ Naturalis Principia Mathematica, Latin for "Mathematical Principles of Natural Philosophy", often referred to as simply the Principia, is a work in three books by Sir Isaac Newton, first published 5 July 1687. Newton also published two further editions, in 1713 and 1726...
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
Brahe
Brahe is the name of a Scanian noble family that was influential in both Danish and Swedish history but has its family roots in Swedish origin. The first member of the family is speculated to have been Verner Braghde from Halland. Better documented is Peder Axelsen Brahe who appears in late 14th...
and Kepler.
Transit of Venus
Horrocks was convinced that Lansberg's tables were inaccurate when Kepler predicted that a near-miss of a transit of VenusVenus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
would occur in 1639. Horrocks believed that the transit would indeed occur, having made his own observations of Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
for years.
Horrocks focused the image of the Sun through a simple telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
onto a piece of card, (see helioscope
Helioscope
A helioscope is an instrument used in observing the sun.The helioscope was first used by Benedetto Castelli and refined by Galileo...
) 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
Julian calendar
The Julian calendar began in 45 BC as a reform of the Roman calendar by Julius Caesar. It was chosen after consultation with the astronomer Sosigenes of Alexandria and was probably designed to approximate the tropical year .The Julian calendar has a regular year of 365 days divided into 12 months...
, or 4 December in the Gregorian calendar
Gregorian calendar
The Gregorian calendar, also known as the Western calendar, or Christian calendar, is the internationally accepted civil calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582, a papal bull known by its opening words Inter...
). 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
William Crabtree
William Crabtree was an astronomer, mathematician, and merchant from Broughton, then a township near Manchester, which is now part of Salford, Greater Manchester, England...
, from his home in Broughton
Broughton, Greater Manchester
Broughton is an inner city area of Salford, in Greater Manchester, England. It lies on the east bank of the River Irwell and A56 road, in the northeastern part of the City of Salford, north-northwest of Manchester city centre and south of Prestwich. Broughton consists of Broughton Park, Higher...
.
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
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
and the Sun. His figure of 59 million miles (95 million kilometres, 0.63 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
) was far from the 93 million miles (150 million kilometers) 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
Johannes Hevelius
Johannes Hevelius Some sources refer to Hevelius as Polish:Some sources refer to Hevelius as German:*Encyplopedia Britannica * of the Royal Society was a councilor and mayor of Danzig , Pomeranian Voivodeship, in the Polish-Lithuanian Commonwealth...
at his own expense in 1662. This paper, which caused great excitement when revealed to members of the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
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 orbitThe Moon's orbit
The Moon completes its orbit around the Earth in approximately 27.3 days . The Earth and Moon orbit about their barycentre , which lies about km from Earth's centre . On average, the Moon is at a distance of about km from the centre of the Earth, which corresponds to about 60...
. He correctly hypothesised that the orbit was elliptical rather than circular, and he anticipated Isaac Newton
Isaac Newton
Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...
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
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!"Horrocks is remembered on a plaque in Westminster Abbey and the lunar crater Horrocks
Horrocks (crater)
Horrocks is a lunar impact crater located entirely within the eroded northeast rim of the much larger walled plain Hipparchus. To the south of Horrocks are the craters Halley and Hind and Rhaeticus to the north. Gyldén and Saunder lie to the west and east, respectively...
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.
Horrocks Avenue, in Garston
Garston
-England:*Garston, Hertfordshire*Garston, Merseyside*Garston railway station-New Zealand:*Garston, New Zealand, town in the Southland District...
, Liverpool, is named after him.
External links
- Chasing Venus, Observing the Transits of Venus Smithsonian Institution Libraries
- BBC report: Celebrating Horrocks' half hour
- Horrocks memorial in Westminster Abbey