From COSMOS: “Alfred Wegener and the continental drift”

Cosmos Magazine bloc


14 August 2020
Jeff Glorfeld

Astronomer’s geological theory didn’t please everyone.

Alfred Wegener during a 1912-1913 expedition to Greenland. Credit: Alfred Wegener Institute, via Wikimedia Commons.

The Earth Institute’s State of the Planet blog recently featured a story headlined 8 Surprising Facts About Marie Tharp, Mapmaker Extraordinaire.

The institute, part of New York’s Columbia University, was celebrating the centenary of the birth of the American geologist and oceanographic cartographer who spent most of her career working at Columbia’s Lamont Geological Observatory.

Beginning in the early 1950s, Tharp, who died on 23 August 2006, “created some of the world’s first maps of the ocean floor”, the blog says.

Her work led to the acceptance of the concepts of plate tectonics and continental drift, and a 2016 article about her in Smithsonian Magazine was headlined: Seeing is believing: How Marie Tharp changed geology forever.

The tectonic plates of the world were mapped in 1996, USGS.

It describes how Tharp’s findings were initially disbelieved and even ridiculed. One of her research partners, geologist Bruce Heezen, rejected her ideas as “girl talk”.

Heezen, who would eventually come around to accepting Tharp’s analysis, claimed “that it sounded like the ‘debunked’ continental drift hypothesis as proposed by Alfred Wegener in 1912”, says a recent article in Forbes magazine.

Just as Tharp had to overcome resistance to her ideas, reaction to Wegener’s theory “was almost uniformly hostile, and often exceptionally harsh and scathing”, says an article published by the University of California Museum of Paleontology (UCMP).

Wegener expanded this “debunked” hypothesis in 1915 into what NASA calls “one of the most influential and controversial books in the history of science: The Origin of Continents and Oceans.

Wegener featured on an Austrian stamp. Credit: raclro / Getty Images.

Wegener was born in Berlin, Germany, on 1 November 1880. Mott T Greene, author of the 2015 biography Alfred Wegener: Science, Exploration, and the Theory of Continental Drift, says he formulated the geological theory of continental drift but he wasn’t a geologist; he was an astronomer who specialised in atmospheric physics.

In 1912, when he proposed his theory of continental displacement, he was 31 and teaching physics and astronomy at the University of Marburg, in southern Germany, Greene says.

He was a renowned balloonist (setting the world record in 1906, with his brother Kurt, for time aloft in a free balloon – more than 52 hours), had been a part of a daring expedition to explore the unmapped north-east coast of Greenland, and was the author of a highly regarded textbook, Thermodynamics of the Atmosphere.

“As important as Wegener’s work on continental drift has turned out to be,” Greene says, “it was largely a sideline to his principal career in atmospheric physics, geophysics and paleo-climatology.”

In 2001, as part of its Earth Observatory website, NASA produced a seven-part series on Wegener.

What began in 1910 as a simple observation, NASA says, became a lifelong fascination. “‘Doesn’t the east coast of South America fit exactly against the west coast of Africa, as if they had once been joined?’ wrote Wegener to his future wife in December 1910. ‘This is an idea I’ll have to pursue’.”

Credit: Lotse / Wikimedia Commons.

He searched out other papers about such continental coincidences. “As he read, his earlier conjecture that the continents had once been joined became a conviction he would boldly champion for the rest of his life.”

In 1915 Wegener wrote The Origin of Continents and Oceans, but because of World War I it went unnoticed outside Germany, NASA says.

“In 1922, however, a third (revised) edition was translated into English, French, Russian, Spanish and Swedish, pushing Wegener’s theory of continental drift to the forefront of debate in the earth sciences.”

By then, NASA says, “Wegener was citing geological evidence that some 300 million years ago all the continents had been joined in a supercontinent stretching from pole to pole. He called it Pangaea (all lands), and said it began to break up about 200 million years ago, when the continents started moving to their current positions.”

Although Wegener’s hypothesis proved to be largely correct, the UCMP notes several problems with it that led to the general lack of support.

“Wegener had no convincing mechanism for how the continents might move,” it says. He thought the continents were “moving through the earth’s crust, like icebreakers plowing through ice sheets, and that centrifugal and tidal forces were responsible for moving the continents”.

In 1930 Wegener returned to Greenland, planning to establish three observation posts. However, as the NASA series describes, the expedition was beset by bad weather, and Wegener perished on the ice, shortly after celebrating his 50th birthday.

See the full article here .

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