Alfred Wegener

Alfred Wegener

Alfred Wegener, ca. 1924-1930
Born (1880-11-01)1 November 1880
Berlin, German Empire
Died November 1930 (aged 50)
Clarinetania, Greenland
Residence Germany
Citizenship German
Nationality German
Fields Meteorology, Geology, Astronomy
Alma mater University of Berlin
Doctoral advisor Julius Bauschinger
Known for Continental drift theory
Influenced Johannes Letzmann

Signature

Alfred Lothar Wegener (1 November 1880 – November 1930) was a German polar researcher, geophysicist and meteorologist.

During his lifetime he was primarily known for his achievements in meteorology and as a pioneer of polar research, but today he is most remembered as the originator of the theory of continental drift by hypothesizing in 1912 that the continents are slowly drifting around the Earth (Kontinentalverschiebung). His hypothesis was controversial and not widely accepted until the 1950s, when numerous discoveries such as palaeomagnetism provided strong support for continental drift, and thereby a substantial basis for today's model of plate tectonics.[1][2] Wegener was involved in several expeditions to Greenland to study polar air circulation before the existence of the jet stream was accepted. Expedition participants made many meteorological observations and achieved the first-ever overwintering on the inland Greenland ice sheet as well as the first-ever boring of ice cores on a moving Arctic glacier.

Biography

Early life and education

Alfred Wegener was born in Berlin on 1 November 1880 as the youngest of five children in a clergyman's family. His father, Richard Wegener, was a theologian and teacher of classical languages at the Berlinisches Gymnasium zum Grauen Kloster. In 1886 his family purchased a former manor house near Rheinsberg, which they used as a vacation home. Today there is an Alfred Wegener Memorial site and tourist information office in a nearby building that was once the local schoolhouse.[3]

Commemorative plaque on Wegener's former school in Wallstrasse

Wegener attended school at the Köllnisches Gymnasium on Wallstrasse in Berlin (a fact which is memorialized on a plaque on this protected building, now a school of music), graduating as the best in his class. Afterward he studied Physics, meteorology and Astronomy in Berlin, Heidelberg and Innsbruck. From 1902 to 1903 during his studies he was an assistant at the Urania astronomical observatory. He obtained a doctorate in astronomy in 1905 based on a dissertation written under the supervision of Julius Bauschinger at Friedrich Wilhelms University (today Humboldt University), Berlin. Wegener had always maintained a strong interest in the developing fields of meteorology and climatology and his studies afterwards focused on these disciplines.

In 1905 Wegener became an assistant at the Aeronautisches Observatorium Lindenberg near Beeskow. He worked there with his brother Kurt, two years his senior, who was likewise a scientist with an interest in meteorology and polar research. The two pioneered the use of weather balloons to track air masses. On a balloon ascent undertaken to carry out meteorological investigations and to test a celestial navigation method using a particular type of quadrant (“Libellenquadrant”), the Wegener brothers set a new record for a continuous balloon flight, remaining aloft 52.5 hours from April 5–7, 1906.[4]

First Greenland expedition and years in Marburg

In that same year 1906, Wegener participated in the first of his four Greenland expeditions, later regarding this experience as marking a decisive turning point in his life. The expedition was led by the Dane Ludvig Mylius-Erichsen and charged with studying the last unknown portion of the northeastern coast of Greenland. During the expedition Wegener constructed the first meteorological station in Greenland near Danmarkshavn, where he launched kites and tethered balloons to make meteorological measurements in an Arctic climatic zone. Here Wegener also made his first acquaintance with death in a wilderness of ice when the expedition leader and two of his colleagues died on an exploratory trip undertaken with sled dogs.

After his return in 1908 and until World War I, Wegener was a lecturer in meteorology, applied astronomy and cosmic physics at the University of Marburg. His students and colleagues in Marburg particularly valued his ability to clearly and understandably explain even complex topics and current research findings without sacrificing precision. His lectures formed the basis of what was to become a standard textbook in meteorology, first written In 1909/1910: Thermodynamik der Atmosphäre (Thermodynamics of the Atmosphere), in which he incorporated many of the results of the Greenland expedition.

On 6 January 1912 he publicized his first thoughts about continental drift in a lecture at a session of the Geologischen Vereinigung at the Senckenberg-Museum, Frankfurt am Main and in three articles in the journal Petermanns Geographischen Mitteilungen.[5]

Second Greenland expedition

After a stopover in Iceland to purchase and test ponies as pack animals, the expedition arrived in Danmarkshavn. Even before the trip to the inland ice began the expedition was almost annihilated by a calving glacier. The Danish expedition leader, Johan Peter Koch, broke his leg when he fell into a glacier crevasse and spent months recovering in a sickbed. Wegener and Koch were the first to winter on the inland ice in northeast Greenland.[6] Inside their hut they drilled to a depth of 25 m with an auger. In summer 1913 the team crossed the inland ice, the four expedition participants covering a distance twice as long as Fridtjof Nansen's southern Greenland crossing in 1888. Only a few kilometers from the western Greenland settlement of Kangersuatsiaq the small team ran out of food while struggling to find their way through difficult glacial breakup terrain. But at the last moment, after the last pony and dog had been eaten, they were picked up at a fjord by the clergyman of Upernavik, who just happened to be visiting a remote congregation at the time.

Later in 1913 after his return Wegener married Else Köppen, the daughter of his former teacher and mentor, the meteorologist Wladimir Köppen. The young pair lived in Marburg, where Wegner resumed his university lectureship.

World War I

As an infantry reserve officer Wegener was immediately called up when the First World War began in 1914. On the war front in Belgium he experienced fierce fighting but his term lasted only a few months: after being wounded twice he was declared unfit for active service and assigned to the army weather service. This activity required him to travel constantly between various weather stations in Germany, on the Balkans, on the Western Front and in the Baltic region.

Nevertheless, he was able in 1915 to complete the first version of his major work, Die Entstehung der Kontinente und Ozeane (“The Origin of Continents and Oceans”). His brother Kurt remarked that Alfred Wegener’s motivation was to “reestablish the connection between geophysics on the one hand and geography and geology on the other, which had become completely ruptured because of the specialized development of these branches of science.”

Interest in this small publication was however low, also because of wartime chaos. By the end of the war Wegener had published almost 20 additional meteorological and geophysical papers in which he repeatedly embarked for new scientific frontiers. In 1917 he undertook a scientific investigation of the Treysa meteorite.

Postwar period and third expedition

Wegener obtained a position as a meteorologist at the German Naval Observatory (Deutsche Seewarte) and moved to Hamburg with his wife and their two daughters. In 1921 he was appointed senior lecturer at the new University of Hamburg. From 1919 to 1923 Wegener did pioneering work on reconstructing the climate of past eras (now known as "paleoclimatology"), closely in collaboration with Milutin Milanković,[7] publishing Die Klimate der geologischen Vorzeit (“The Climates of the Geological Past”) together with his father-in-law, Wladimir Köppen, in 1924.[8] In 1922 the third, fully revised edition of “The Origin of Continents and Oceans” appeared, and discussion began on his theory of continental drift, first in the German language area and later internationally. Withering criticism was the response of most experts.

In 1924 Wegener was appointed to a professorship in meteorology and geophysics in Graz, which finally provided him with a secure position for himself and his family. He concentrated on physics and the optics of the atmosphere as well as the study of tornados. Scientific assessment of his second Greenland expedition (ice measurements, atmospheric optics, etc.) continued to the end of the 1920s.

In November 1926 Wegener presented his continental drift theory at a symposium of the American Association of Petroleum Geologists in New York City, again earning rejection from everyone but the chairman. Three years later the fourth and final expanded edition of “The Origin of Continents and Oceans” appeared.

In 1929 Wegener embarked on his third trip to Greenland, which laid the groundwork for a later main expedition and included a test of an innovative, propeller-driven snowmobile.

Fourth and last expedition

Wegener (left) and Villumsen (right) in Greenland; November 1, 1930.

Wegener's last Greenland expedition was in 1930. The 14 participants under his leadership were to establish three permanent stations from which the thickness of the Greenland ice sheet could be measured and year-round Arctic weather observations made. Wegener felt personally responsible for the expedition's success, as the German government had contributed $120,000 ($1.5 million in 2007 dollars). Success depended on enough provisions being transferred from West camp to Eismitte ("mid-ice") for two men to winter there, and this was a factor in the decision that led to his death. Owing to a late thaw, the expedition was six weeks behind schedule and, as summer ended, the men at Eismitte sent a message that they had insufficient fuel and so would return on 20 October.

Vehicles used by the 1930 expedition (stored).

On 24 September, although the route markers were by now largely buried under snow, Wegener set out with thirteen Greenlanders and his meteorologist Fritz Loewe to supply the camp by dog sled. During the journey the temperature reached −60 °C (−76 °F) and Loewe's toes became so frostbitten they had to be amputated with a penknife without anesthetic. Twelve of the Greenlanders returned to West camp. On 19 October the remaining three members of the expedition reached Eismitte. There being only enough supplies for three at Eismitte, Wegener and Rasmus Villumsen took two dog sleds and made for West camp. They took no food for the dogs and killed them one by one to feed the rest until they could run only one sled. While Villumsen rode the sled, Wegener had to use skis. They never reached the camp. The expedition was completed by his brother, Kurt Wegener.

This expedition inspired the Greenland expedition episode of Adam Melfort in John Buchan's 1933 novel A Prince of the Captivity.

Death

Six months later, on 12 May 1931, Wegener's body was found halfway between Eismitte and West camp. It had been buried (by Villumsen) with great care and a pair of skis marked the grave site. Wegener had been fifty years of age and a heavy smoker and it was believed that he had died of heart failure brought on by overexertion. His body was reburied in the same spot by the team that found him and the grave was marked with a large cross. After burying Wegener, Villumsen had resumed his journey to West camp but was never seen again. Villumsen was twenty three when he died and it is estimated that his body, and Wegener's diary, now lie under more than 100 metres (330 ft) of accumulated ice and snow.

Continental drift theory

Alfred Wegener first thought of this idea by noticing that the different large landmasses of the Earth almost fit together like a jigsaw puzzle. The Continental shelf of the Americas fit closely to Africa and Europe, and Antarctica, Australia, India and Madagascar fitted next to the tip of Southern Africa. But Wegener only took action after reading a paper in 1911 and seeing that a flooded land-bridge contradicts isostasy.[9] Wegener's main interest was meteorology, and he wanted to join the Denmark-Greenland expedition scheduled for mid-1912. He presented his Continental Drift hypothesis on 6 January 1912. He analyzed either side of the Atlantic Ocean for rock type, geological structures and fossils. He noticed that there was a significant similarity between matching sides of the continents, especially in fossil plants.

Fossil patterns across continents (Gondwana).

From 1912, Wegener publicly advocated the existence of "continental drift", arguing that all the continents were once joined together in a single landmass and have drifted apart. He supposed that the mechanisms might be the centrifugal force of the Earth's rotation ("Polflucht") or the astronomical precession caused the drift. Wegener also speculated on sea-floor spreading and the role of the mid-ocean ridges, stating: the Mid-Atlantic Ridge ... zone in which the floor of the Atlantic, as it keeps spreading, is continuously tearing open and making space for fresh, relatively fluid and hot sima [rising] from depth.[10] However, he did not pursue these ideas in his later works.

In 1915, in The Origin of Continents and Oceans (Die Entstehung der Kontinente und Ozeane), Wegener drew together evidence from various fields to advance the theory that there had once been a giant continent which he named "Urkontinent"[11] (German for "primal continent", analogous to the Greek "Pangaea",[12] meaning "All-Lands" or "All-Earth"). Expanded editions during the 1920s presented further evidence. The last edition, just before his untimely death, revealed the significant observation that shallower oceans were geologically younger.

Wegener during J.P. Koch's Expedition 1912 - 1913 in the winter base "Borg".

Reaction

In his work, Wegener presented a large amount of observational evidence in support of continental drift, but the mechanism remained elusive, partly because Wegener's estimate of the velocity of continental motion, 250 cm/year, was too high.[13] (The currently accepted rate for the separation of the Americas from Europe and Africa is about 2.5 cm/year).[14]

While his ideas attracted a few early supporters such as Alexander Du Toit from South Africa, Arthur Holmes in England [15] and Milutin Milanković in Serbia for whom continental drift theory was the premise in investigating polar wandering,[16][17] the hypothesis was initially met with skepticism from geologists who viewed Wegener as an outsider, and were resistant to change.[15] The one American edition of Wegener's work, published in 1925, which was written in "a dogmatic style that often results from German translations",[15] was received so poorly that the American Association of Petroleum Geologists organized a symposium specifically in opposition to the continental drift hypothesis.[18] The opponents argued, as did the Leipziger geologist Franz Kossmat, that the oceanic crust was too firm for the continents to "simply plough through".

Wegener's fit of the supercontinent at the 200m isobath (the continental shelves), an idea he had since at least 1910, was a good match.[15] Part of the reason Wegener's ideas were not initially accepted was based on his proposed fit of the continents, with Charles Schuchert commenting:

During this vast time [of the split of Pangea] the sea waves have been continuously pounding against Africa and Brazil and in many places rivers have been bringing into the ocean great amounts of eroded material, yet everywhere the geographic shore lines are said to have remained practically unchanged! It apparently makes no difference to Wegener how hard or how soft are the rocks of these shore lines, what are their geological structures that might aid or retard land or marine erosion, how often the strand lines have been elevated or depressed, and how far peneplanation has gone on during each period of continental stability. Furthermore, sea-level in itself has not been constant, especially during the Pleistocene, when the lands were covered by millions of square miles of ice made from water subtracted out of the oceans. In the equatorial regions, this level fluctuated three times during the Pleistocene, and during each period of ice accumulation the sea-level sank about 250 feet.

The comment was based on the misapprehension that Wegener's fit was judged along the current coastline, while Wegener was using the 200m isobath. Wegener, who was in the audience, made no attempt to defend his work, (possibly because of an inadequate command of the English language). Supporters such as Toit, also contributed to this misunderstanding of the method of the continental fitting, commenting (after Wegener's death) "most persons view the continental shelf as an integral part of the continental block, and criticise Wegener for endeavoring to fit together the masses by their present coastlines instead of by the submerged margins of the shelves."[15]

In 1943 George Gaylord Simpson wrote a vehement attack on the theory (as well as the rival theory of sunken land bridges) and put forward his own permanentist views.[19] Alexander du Toit wrote a rejoinder in the following year.[20]

Modern developments

The tectonic plates of the world were mapped in the second half of the 20th century.

In the early 1950s, the new science of paleomagnetism pioneered at the University of Cambridge by S. K. Runcorn and at Imperial College by P.M.S. Blackett was soon producing data in favour of Wegener's theory. By early 1953 samples taken from India showed that the country had previously been in the Southern hemisphere as predicted by Wegener. By 1959, the theory had enough supporting data that minds were starting to change, particularly in the United Kingdom where, in 1964, the Royal Society held a symposium on the subject.[21]

Additionally, the 1960s saw several developments in geology, notably the discoveries of seafloor spreading and Wadati-Benioff zones, and this led to the rapid resurrection of the continental drift hypothesis and its direct descendant, the theory of plate tectonics. Maps of the geomorphology of the ocean floors created by Marie Tharp in cooperation with Bruce Heezen were an important contribution to the paradigm shift that was starting. Wegener was then recognized as the founding father of one of the major scientific revolutions of the 20th century.

With the advent of the Global Positioning System (GPS), it became possible to measure continental drift directly.[22]

Awards and honors

The Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, was established in 1980 on his centenary. It awards the Wegener Medal in his name.[23] The crater Wegener on the Moon and the crater Wegener on Mars, as well as the asteroid 29227 Wegener and the peninsula where he died in Greenland (Wegener Peninsula near Ummannaq, 71°12′N 51°50′W / 71.200°N 51.833°W / 71.200; -51.833), are named after him.[24]

The European Geosciences Union sponsors an Alfred Wegener Medal & Honorary Membership "for scientists who have achieved exceptional international standing in atmospheric, hydrological or ocean sciences, defined in their widest senses, for their merit and their scientific achievements."[25]

See also

References

  1. ↑ Spaulding, Nancy E.; Namowitz, Samuel N. (2005). Earth Science. Boston: McDougal Littell. ISBN 0-618-11550-1.
  2. ↑ McIntyre, Michael; Eilers, H. Peter; Mairs, John (1991). Physical geography. New York: Wiley. p. 273. ISBN 0-471-62017-3.
  3. ↑ The memorial site is the Gedenkstätte Zechlinerhütte, see http://www.zechlinerhuette.com/de/tourismusinfo/wegener_gedenkstaette.php (in German)
  4. ↑ Victor Silberer: Die Dauerfahrt von 52½ Stunden. In: Wiener Luftschiffer-Zeitung 5, Heft 8, 1906, S. 156–157
  5. ↑ "Presse - AWI" (PDF).
  6. ↑ Dansgaard W (2004). Frozen Annals Greenland Ice Sheet Research. Odder, Denmark: Narayana Press. p. 124. ISBN 87-990078-0-0.
  7. ↑ introduction to the English edition, The Climates of the Geological Past, (2015), retrieved August 28, 2015
  8. ↑ Köppen, W. & Wegener, A. (1924): Die Klimate der geologischen Vorzeit, Borntraeger Science Publishers. In English as The Climates of the Geological Past (2015).
  9. ↑ Arldt, Th. (1910). "Referat Scharff: Ueber die Beweissgruende fuer eine fruehere Landbruecke zwischen Nordeuropa und Nordamerika". Naturwiss. Rdsch. (in German) 25: 86–87., Scharff, R. F. (1909). "Ueber die Beweissgruende fuer eine fruehere Landbruecke zwischen Nordeuropa und Nordamerika". Proc. Royal Irish Acad. (in German) 28: 1–28. cited in Flügel, Helmut W. (December 1980). "Wegener-Ampferer-Schwinner: Ein Beitrag zur Geschichte der Geologie in Österreich" [Wegener-Ampferer-Schwinner: A Contribution to the History of the Geology in Austria] (PDF). Mitt. österr. Geol. Ges. (in German) 73.
  10. ↑ Jacoby, W. R. (January 1981). "Modern concepts of earth dynamics anticipated by Alfred Wegener in 1912". Geology 9: 25–27. Bibcode:1981Geo.....9...25J. doi:10.1130/0091-7613(1981)9<25:MCOEDA>2.0.CO;2.
  11. ↑ according to the OED, 2d edition (1989), the word is not found in the 1915 edition of Wegener's text; it appears in the 1920 edition but with no indication that Wegener coined it
  12. ↑ W.A.J.M. van Waterschoot van der Gracht, Bailey Willis, Rollin T. Chamberlin, John Joly, G.A.F. Molengraaff, J.W. Gregory, Alfred Wegener, Charles Schuchert, Chester R. Longwell, Frank Bursley Taylor, William Bowie, David White, Joseph T. Singewald, Jr., and Edward W. Berry (1928). W.A.J.M. van Waterschoot van der Gracht, ed. Theory of Continental Drift: a symposium on the origin and movement of land masses both intercontinental and intracontinental as proposed by Alfred Wegener, A Symposium of the American Association of Petroleum Geologists (AAPG, 1926). Tulsa, OK. p. 240.
  13. ↑ University of California Museum of Paleontology, Alfred Wegener (1880-1930) (accessed 30 April 2015).
  14. ↑ Unavco Plate Motion Calculator (accessed 30 April 2015).
  15. 1 2 3 4 5 Drake, Ellen T. (1 January 1976). "Alfred Wegener's reconstruction of Pangea". Geology 4 (1): 41. Bibcode:1976Geo.....4...41D. doi:10.1130/0091-7613(1976)4<41:AWROP>2.0.CO;2.
  16. ↑ Mathematische Klimalehre und astronomische Theorie der Klimaschwankungen. in W. Köppen & R. Geiger (Hrsg.): Handbuch der Klimatologie Bd. 1: Allgemeine Klimalehre. Borntraeger, Berlin, 1930
  17. ↑ http://elibrary.matf.bg.ac.rs/bitstream/handle/123456789/3675/mm35F.pdf?sequence=1
  18. ↑ H. Tristam Engelhardt Jr and Arthur L. Caplan, ed. (1987). Scientific Controversies: Case studies in the resolution and closure of disputes in science and technology. pp. 210–211.
  19. ↑ Simpson, G.G. (1943). "Mammals and the Nature of Continents". American Journal of Science 241: 1–31. doi:10.2475/ajs.241.1.1.
  20. ↑ du Toit, A. (1944). "Tertiary Mammals and Continental Drift". American Journal of Science 242 (3): 145–63. doi:10.2475/ajs.242.3.145.
  21. ↑ Frankel, H. (1987). "The Continental Drift Debate". In H.T. Engelhardt Jr and A.L. Caplan. Scientific Controversies: Case Solutions in the resolution and closure of disputes in science and technology. Cambridge University Press. ISBN 978-0-521-27560-6.
  22. ↑ Brady Haran (4 June 2003). "The millimetre men". BBC News UK.
  23. ↑ "2005 Annual report", page 259, Alfred Wegener Institute
  24. ↑ "JPL Small-Body Database Browser".
  25. ↑ "EGU: Awards & Medals". Retrieved 2009-09-16.

Selected works

External links

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