James Croll (2 January 1821 – 15 December 1890) was a 19th century Scottish scientist who developed a theory of climate change based on changes in the earth's orbit. January 2 is the second day of the year in the Gregorian calendar. ... The coronation banquet for George IV 1821 was a common year starting on Monday (see link for calendar). ... December 15 is the 349th day of the year (350th in leap years) in the Gregorian calendar. ... 1890 (MDCCCXC) was a common year starting on Wednesday (see link for calendar) of the Gregorian calendar (or a common year starting on Friday of the Julian calendar). ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... Motto: (Eng: No one provokes me with impunity)1 Anthem: Multiple unofficial anthems Capital Edinburgh Largest city Glasgow Official language(s) English, Gaelic, Scots 2 Government Constitutional monarchy  - Queen of the UK Queen Elizabeth II  - Prime Minister of the UK Tony Blair MP  - First Minister Jack McConnell MSP Unification    - by... The physicist Albert Einstein is probably the most famous scientist of our time. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ...

Life

James Croll was born in 1821 on the farm of Little Whitefield, near Wolfhill in Perthshire, Scotland (NO1733). He was largely self-educated, teaching himself physics and astronomy. At 16 he became an apprentice wheelwright at Collace near Wolfhill, and then because of health problems a tea merchant in Elgin, Moray. He married Isabella Macdonald in 1848. The coronation banquet for George IV 1821 was a common year starting on Monday (see link for calendar). ... Perthshire (Siorrachd Pheairt in Gaelic) was a county in central Scotland, which extended from Strathmore in the east, to the Pass of Drumochter in the north, Rannoch Moor and Ben Lui in the west, and Aberfoyle in the south. ... Motto: (Eng: No one provokes me with impunity)1 Anthem: Multiple unofficial anthems Capital Edinburgh Largest city Glasgow Official language(s) English, Gaelic, Scots 2 Government Constitutional monarchy  - Queen of the UK Queen Elizabeth II  - Prime Minister of the UK Tony Blair MP  - First Minister Jack McConnell MSP Unification    - by... The British national grid reference system is a system of geographic grid references commonly used in Great Britain, different from using latitude or longitude. ... Physics (from the Greek, (phúsis), nature and (phusiké), knowledge of nature) is the science concerned with the discovery and understanding of the fundamental laws which govern matter, energy, space and time. ... A giant Hubble mosaic of the Crab Nebula, a supernova remnant. ... Wheelwright - a person that repairs and aligns defective wheels of automotive vehicles, such as automobiles, buses, and trucks. ... Elgin is a town in Moray the North of Scotland. ... Moray (Moireibh in Gaelic), one of the 32 unitary council regions (or areas) of Scotland, lies in the north-east of the country and borders on the regions of Aberdeenshire and Highland. ... 1848 (MDCCCXLVIII) was a leap year starting on Saturday of the Gregorian calendar. ...

In the 1850s he managed a temperance hotel in Blairgowrie, and was then an insurance agent in Glasgow, Edinburgh and Leicester. In 1859 he became a janitor in the museum at the Andersonian College and Museum, Glasgow, so as to have access to books to allow him to develop his ideas. // Events and Trends Technology Production of steel revolutionised by invention of the Bessemer process Benjamin Silliman fractionates petroleum by distillation for the first time First transatlantic telegraph cable laid First safety elevator installed by Elisha Otis Science Charles Darwin publishes The Origin of Species, putting forward the theory of evolution... Between 1830 and 1840, most temperance organizations began to argue that the only way to prevent drunkenness was to eliminate the consumption of alcohol. ... See Blairgowrie for other places of this name. ... For other uses, see Glasgow (disambiguation). ... Edinburgh (pronounced ; Dùn Èideann () in Scottish Gaelic) is the capital of Scotland and its second-largest city. ... Leicester city centre, looking towards the Clock Tower Leicester (pronounced ) is a large city in the East Midlands of England. ... 1859 (MDCCCLIX) is a common year starting on Saturday of the Gregorian calendar (or a common year starting on Monday of the Julian calendar). ... The University of Strathclyde is a university in Glasgow, Scotland. ...

From 1864, Croll corresponded with Sir Charles Lyell^[1], on links between ice ages and variations in the earth's orbit. This led to a position in the Edinburgh office of the Geological Survey of Scotland, as keeper of maps and correspondence, where the director, Sir Archibald Geikie, encouraged his research. He published a number of books and papers which "were at the forefront of contemporary science"^[2], including Climate and Time, in Their Geological Relations in 1875. He corresponded with Charles Darwin on erosion by rivers. 1864 (MDCCCLXIV) was a leap year starting on Friday (see link for calendar) of the Gregorian calendar or a leap year starting on Sunday of the 12-day-slower Julian calendar. ... Charles Lyell The frontispiece from Principles of Geology Sir Charles Lyell, 1st Baronet Kt (November 14, 1797 – February 22, 1875), Scottish lawyer, geologist, and populariser of uniformitarianism. ... Edinburgh (pronounced ; Dùn Èideann () in Scottish Gaelic) is the capital of Scotland and its second-largest city. ... The British Geological Survey is a publicly-funded body which aims to advance geoscientific knowledge of the United Kingdom landmass and its continental shelf by means of systematic surveying, monitoring and research. ... Sir Archibald Geikie (December 28, 1835 _ November 10, 1924), Scottish geologist, was born at Edinburgh. ... 1875 (MDCCCLXXV) was a common year starting on Friday (see link for calendar). ... Charles Robert Darwin FRS (12 February 1809 – 19 April 1882) was an English naturalist who achieved lasting fame by producing considerable evidence that species originated through evolutionary change, at the same time proposing the scientific theory that natural selection is the mechanism by which such change occurs. ... Severe soil erosion in a wheat field near Washington State University, USA. Erosion is the displacement of solids (soil, mud, rock and other particles) by the agents of wind, water or ice, by downward or down-slope movement in response to gravity or by living organisms (in the case of...

In 1876, he was elected Fellow of the Royal Society, and awarded an honorary degree by the University of St Andrews. He retired in 1880 because of ill health, and died in 1890. 1876 (MDCCCLXXVI) was a leap year starting on Saturday. ... The premises of the Royal Society in London (first four properties only). ... St Marys College Bute Medical School Postgraduate Students Affiliations 1994 Group Website www. ... 1880 (MDCCCLXXX) was a leap year starting on Thursday (see link for calendar). ... 1890 (MDCCCXC) was a common year starting on Wednesday (see link for calendar) of the Gregorian calendar (or a common year starting on Friday of the Julian calendar). ...

Theory of ice ages

Using formulae for orbital variations developed by Leverrier (which had led to the discovery of Neptune), Croll developed a theory of the effects of variations of the earth's orbit on climate cycles. His idea was that decreases in winter sunlight would favour snow accumulation, and for the first time coupled this to the idea of a positive ice-albedo feedback to amplify the solar variations. He suggested that when orbital eccentricity is high, then winters will tend to be colder when earth is farther from the sun in that season and hence, that during periods of high orbital eccentricity, ice ages occur on 22,000 year cycles in each hemisphere, and alternate between southern and northern hemispheres, lasting approximately 10,000 years each. This is wrong, but that was not known then. Urbain Le Verrier. ... Atmospheric characteristics Surface pressure ≫100 MPa Hydrogen - H2 80% ±3. ... Albedo is a ratio of scattered to incident electromagnetic radiation power. ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ...

Croll's theory predicted multiple ice ages, asynchronous in northern and southern hemispheres, and that the last ice ages should have ended about 80,000 years ago. Evidence was just then emerging of multiple ice ages, and geologists were interested in a theory to explain this. Geologists were not then able to date sediments accurately enough to determine if glaciation was synchronous between the hemispheres, though the limited evidence more pointed towards synchronicity than not. More crucially, estimates of the recession rate of the Niagara Falls indicated that the last ice age ended 6,000 to 35,000 years ago - a large range, but enough to rule out Croll's theory, to those who accepted the measurements. Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... A glaciation (a created composite term meaning Glacial Period, referring to the Period or Era of, as well as the process of High Glacial Activity), often called an ice age, is a geological phenomenon in which massive ice sheets form in the Arctic and Antarctic and advance toward the equator. ... For other uses, see Niagara Falls (disambiguation). ...

Croll's work was widely discussed, but by the end of the 19th century, his theory was generally disbelieved. However, the basic idea of orbitally-forced insolation variations influencing terrestrial temperatures was further developed by Milutin Milankovitch and eventually, in modified form, triumphed in 1976. Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... Milutin Milanković (1879-1958) Milutin Milanković (a. ... 1976 (MCMLXXVI) was a leap year starting on Thursday. ...

Works

• 1857: The Philosophy of Theism
• 1875: Climate and Time, in Their Geological Relations
• 1885: Climate and Cosmology
• 1896: posthumous publication of Autobiographical Sketch of James Croll, With Memoir of His Life and Work, edited by J. C. Irons

Notes

1. ^ Index of some of Croll's correspondence. NAHSTE. Retrieved on 2006-07-30.
2. ^ Prof David Crichton. Croll: a forgotten hero of Perth. (Copy at web.archive.org). Retrieved on 2004-10-11.

2006 (MMVI) is a common year starting on Sunday of the Gregorian calendar. ... July 30 is the 211th day (212th in leap years) of the year in the Gregorian Calendar, with 154 days remaining. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... October 11 is the 284th day of the year (285th in leap years) in the Gregorian calendar. ...

References

• Imbrie and Imbrie, "Ice ages - solving the mystery", Harvard University Press, 1979.
• Gribbin & Gribbin, "Ice Age", Allen Lane, 2001.

See also

• Milankovitch cycles

Milankovitch cycles are the collective effect of changes in the Earths movements upon its climate, named after Serbian geophysicist Milutin Milanković. The eccentricity, axial tilt, and precession of the Earths orbit vary in several patterns, resulting in 100,000 year ice age cycles of the Quaternary glaciation over...

External links

• James Croll - unsung scientist