Alfred Lothar Wegener (1880-1930), German meteorologist, Arctic explorer and a brilliant interdisciplinary scientist, is best known as for his theory of "continental displacement" (that became famous, later, as the theory of continental drift). Since the technological means for proving the theory had not yet been developed and the idea was a radical departure from the scientific thinking of the time, Wegener's theory was widely rejected during his lifetime. After gradual accumulation of evidence in support of the idea, the theory finally gained acceptance in the early sixties. This paper gives a brief biography of Alfred Wegener, his theory of continental drift and other contributions to the world of science. Early Life & Education

Alfred Wegener was born on November 1, 1880 in Berlin. His father was a minister and ran an orphanage. Even as a young boy Wegener was interested in walking, skating and hiking that he put to use in several Arctic expeditions later in his life. Wegener studied in Berlin, Heidelberg and Innsbruck and earned his PhD in astronomy from the University of Berlin in 1904. However, he was more interested in geophysics and started to study the emerging sciences of meteorology and climatology. He spent most of his life studying these fields rather than astronomy. ("Alfred Wegener 1880-1930," 1998- A Science Odyssey Web site; Waggoner, 1996.) In 1906 he made his first expedition to Greenland to study polar air circulation. On his return, he joined the University of Marburg as a lecturer, but again took time off in 1912-13 on another expedition to Greenland. Before going on his second Greenland expedition, Wegener got married to the daughter of one of the leading meteorologists in Germany. He also joined the Army and fought in World War I before being discharged in 1914 after being wounded.

Initial Idea of the Theory of Continental Drift

While at Marburg, in 1911, Wegener noticed the matching coastlines of South America and Africa on either side of the Atlantic and also came across a scientific paper that listed fossils of identical plants and animals found on opposite sides of the Atlantic. He was intrigued by the phenomenon and began to investigate further the similarity of organisms separated by vast oceans. The existing scientific theory at the time explained such similarity by the conjecture that "land bridges" (now sunken) had once connected far-flung continents. (Waggoner, 1996.)

Wegener was not convinced by the theory of "land bridges" and combined the 'remarkable fit' (like a jig-saw puzzle) of the African and South American coastlines with the geological and paleontological evidence to develop his theory of Continental drift. He first put forward the idea in 1912 that the continents had at one time been joined together in one land mass before drifting apart.

Evidence for the Theory

Wegener was not the first person to suggest the possibility and knew that in order for such a revolutionary theory a lot of back-up evidence was required. He, therefore, set about the task of finding the evidence with typical tenacity. He noticed that large-scale geological features on separated continents often matched very closely when the continents were brought together. For example, the Appalachian mountains of eastern North America matched with the Scottish Highlands, and the distinctive rock strata of the Karroo system of South Africa were identical to those of the Santa Catarina system in Brazil. Further evidence for his theory was found in fossils. It was discovered that fossils found in many places indicated a climate utterly different from the present-day climate. This was evident in, for example, the discovery of fossils of tropical plants on the Arctic island of Spitsbergen. (Waggoner, 1996) All of these facts supported Wegener's theory of "continental drift." The theory was put together by Wegener in his book The Origin of Continents and Oceans which he published in 1915. Expanded editions of the book were published in 1920, 1922, and 1929.

Panagea

In his "Origin of Continents and Oceans" Wegener explained that all the continents had been joined...

He proposed that the Western Hemisphere continents moved eastward and butted against the western shores of Europe and Africa and the Southern Hemisphere continents had nestled together on the southern flank of the "Pangaea." Wegener suggested that under the action of forces associated with the rotation of the earth, the continents had broken apart, opening up the Atlantic and Indian oceans. (Wilson, 1963)
Reaction to Wegener's Theory

Reaction to Wegener's theory in the scientific world was mostly hostile and led to great contraversy. As an example Dr. Rollin T. Chamberlin of the University of Chicago said, "Wegener's hypothesis in general is of the footloose type, in that it takes considerable liberty with our globe, and is less bound by restrictions or tied down by awkward, ugly facts than most of its rival theories." (Quoted by Waggoner, 1996)

The above quoted criticism of Wegener was particularly vicious but some of the reluctance to accept the theory of Continental Drift was not without reason. Although Wegener had found compelling evidence about the similarities of geology and fossils found in far-flung continents, his explanation of how the continents had moved was not very convincing. Wegener thought that the continents had moved (and continued to move) due to the centrifugal and tidal forces that were the result of the rotation of the earth. He also thought that the continents were moving through the earth's crust, "like icebreakers plowing through ice sheets." Opponents of the theory pointed out that such "plowing through oceanic crust" would distort continents beyond recognition. They were also of the opinion that "centrifugal and tidal forces" were too weak to move continents. Wegener's opponents also pounced on some incorrect predictions by him. For example, he suggested that North America and Europe were moving apart at over 250 cm per year. Most geologists, therefore, continued to believe in static continents and land bridges until the 1950s.

Another reason for the hostility to Wegener was that most leading geologists of his time considered him to be a "mere meteorologist" -- an outsider who was meddling in their field. (Watson, 1999)

Support for his Theory

There were some notable exceptions among the scientists who supported Wegener's theory during his lifetime, the South African geologist Alexander Du Toit being one of them. He supported the theory as an explanation for the close similarity of strata and fossils between Africa and South America. A Swiss geologist, Emile Argand, also considered the theory of continental collisions as the best explanation for the folded and buckled strata that he had observed in the Swiss Alps.

Corroboration

Increased exploration of the Earth's crust, notably the ocean floor, began in the 1950s and by the late 1960s, the theory of " plate tectonics" was supported and accepted by almost all geologists. Although the 'plate tectonics' differs in part from Wegener's theory about the movement of continents "plowing through the ocean floor" it did prove conclusively that the continents (and the oceanic crust) are not static and both move. Scientists have also mapped and explored the great system of oceanic ridges that are the sites of frequent earthquakes, where molten rock rises from below the crust and hardens into new crust. It is now even possible to measure the speed of continental plates' movement with a high degree of accuracy by using satellite technology. All of this validates Wegener's basic theory of continental drift.

Other Contributions

As we noted in the introduction, Wegener was a versatile inter-disciplinary scientist and he made other significant contributions to Science besides his theory of 'Continental Drift.' He led several expeditions to Greenland where he conducted research to measure the thickness of ice and the rate of drift. He made a significant observation in the 4th edition of his book, "The Origins of the Continents" that shallower oceans were…