Jeremiah Horrocks
Jeremiah Horrocks (* 1619 in Toxteth Park, near Liverpool in Lancashire, † January 3, 1641 ), sometimes also written Jeremiah Horrox , was an English astronomer .
Life
Horrocks was born in Toxteth Park, near Liverpool in Lancashire in 1619 . His father was a small farmer. He came from a Puritan family and studied from 1632 at Cambridge University , which he left without a degree in 1635 for unknown reasons to settle in Much Hoole , Lancashire, probably as a tutor.
In Cambridge he got to know the work of Johannes Kepler , Tycho Brahe , Philip Lansberg and other astronomers. He investigated the lunar orbit with the help of Kepler's laws , studied the tides and discovered the mutual orbital disturbances of Jupiter and Saturn .
On the basis of Lansberg's tables and years of his own observations of Venus , Horrocks predicted a Venus transit for the end of 1639. Kepler had calculated the transit of Mercury and Venus in 1631, but his calculations only lasted until 1636. The transit of Mercury on November 7th, 1631 was observed by Pierre Gassendi in Digne , the transit of Venus on December 6th, 1631 could not be seen from Europe.
Horrocks focused the image of the sun through a telescope on a piece of cardboard, thus observing the event. He calculated the transit for his observation site Much Hoole to be around 3 p.m. on November 24th July. / 4th December 1639 greg. . His first view of Venus in front of the sun was at 3:15 p.m.
This first secured observation of a Venus transit allowed the orbit parameters of Venus to be determined more precisely. He was also able to get a good estimate of the diameter of Venus. The resulting distance between earth and sun of 95 million kilometers is indeed too small compared to the value known today of 150 million kilometers, but it was a significant improvement compared to the value from antiquity , which was used until then, which was too low by a factor of 20 .
Since his calculations were only completed shortly before the event, he was unable to notify astronomers other than his friend William Crabtree , so that the transit was only observed by two people. Horrocks' results were not published until 20 years after his death, but partially falsified for reasons of competition. He died of a sudden illness on January 3, 1641 and was buried in the old chapel of Toxteth or in its churchyard.
The moon crater Horrocks and the asteroid (3078) Horrocks are named after him. The same applies to the Horrocks Block , a cliff on Alexander I Island in Antarctica.
literature
- Arundell Blount Whatton: Memoir of the Life and Laboratories of the Rev. Jeremiah Horrox . William Hunt and Company, London 1875. archive.org
- Wilbur Applebaum: Venus Seen on the Sun: The First Observation of a Transit of Venus by Jeremiah Horrocks . Brill, Leiden / Boston 2012, ISBN 978-90-04-22193-2 .
- Horrocks, Jeremiah . In: Encyclopædia Britannica . 11th edition. tape 13 : Harmony - Hurstmonceaux . London 1910, p. 711 (English, full text [ Wikisource ]).
Web links
| personal data | |
|---|---|
| SURNAME | Horrocks, Jeremiah |
| ALTERNATIVE NAMES | Horrocks, Jeremiah; Horrox, Jeremiah; Horroccius, Jeremias; Horroxius, Jeremias |
| BRIEF DESCRIPTION | English astronomer |
| DATE OF BIRTH | 1619 |
| PLACE OF BIRTH | Toxteth Park near Liverpool |
| DATE OF DEATH | January 3, 1641 |