1. In 1912, when Alfred Wegener proposed in print that Earth's continents floated on denser and more stable material below, he was openly ridiculed and even scorned by his colleagues. Not until several decades later did his ideas receive any acceptance. Today he stands as the forefather of modern plate tectonics because of his theory of continental drift. His widely accepted theory of land displacement holds that Earth's continents have been in motion throughout geologic time.
Wegener believe that there was once a single supercontinent, which he called Pangea (or Pangaea). He said that Pangea broke apart millions of years ago to form two large continents. He called the one in the northern hemisphere Laurasia and the one in the southern hemisphere Gondwanaland. After a very long span of centuries, Wegener said, Laurasia split to form North America, most of Asia, Greenland, and a large section of Europe. Gondwanaland became Africa, South America, Australia, India, and Antarctica. Wegener believed that the land masses drifted for millions of years before assuming their present shapes and arriving at their present locations. He was led to this notion by the congruity he observed in the shorelines of the lands bordering the Atlantic Ocean and several other kinds of evidence. Further, he said, the process of continental drift is still going on--the continents are still on the move.
Alfred Wegener, who was educated to be a meteorologist and an Arctic climatologist, insisted that his theory was correct because of the evidence he saw. To support his ideas about continental drift, Wegener pointed to the similarities in the fossils of the southern continents. Fossils of the same sort from ferns and freshwater reptiles had been found in all of the southern continents. He saw this as evidence that all the lands south of the equator had once been part of a single land mass. He argued that such land-based life forms could never have crossed the thousands of miles of open ocean that now separate these land masses. His critics scoffed because the physical model that Wegener proposed to explain the movement of continents did not fit what was then known about the physics of the Earth.
For the next 30 years or so, scientists paid little attention to Wegeners's theory. In the 1960's , however, geologists discovered that the ocean floors had been spreading, thus influencing the shapes and sizes of the continents. This new theory, called plate tectonics, provided a mechanism that made sense in physical terms to account for Wegener's idea of continental drift. Although the continents themselves do not drift, as Wegener proposed, he was correct in his thesis that Earth's surface is not fixed. He was a man well ahead of his time whose insight went beyond safe and conventional thinking. So important is Wegener to our current understainding of plate tectonics that in the 1970s a crater on the dark side of the moon was named for him, to honor his courage and wisdom.
Tragically, Alfred Wegener never lived to see his ideas accepted
by the scienfific community. He perished while attempting to cross
Greenland from a camp on the ice cap in the winter of 1930. His
purpose was to learn more about atmospheric conditions in the
Arctic in order to beter predict world weather patterns.
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