November 1, 2011 - Happy Birthday, Alfred Wegener

nOncenupon a time, a very long time ago, India was all by itself, a verynlarge island floating along in a sea it liked to think of as thenIndian Sea. It was minding its own business, when all of a sudden—

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nWHAM!nn

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nIndianslammed into a huge continent. The biggest continent in the world, asna matter of fact: Asia.

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nIndia’sncollision with Asia pushed up the highest mountains on the planet,nthe Himalayas, just like an auto collision might push up and rumple ancar hood. And the slo-mo collision is still ongoing! India is stillnpushing into the larger continental mass, still pushing up mountains.nThe Himalayas are getting higher—2 centimeters per year higher.

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nWho’d have thunk?

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nThenideas that continental and sub-continental chunks of land driftnaround, that they “float” above and move around on the innernmantle,nthat continents can move from the poles to the equator or vice versa,nthat seas can open up or shrink and disappear as land masses pullnaway from each other or collide with each other—all thesenunlikely-sounding ideas are the fruits of Alfred Wegener’s brain.

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nOurnbirthday boy was born in Germany in 1880. He grew up to be angeophysicist (a scientist who studies the physics of the Earth, suchnas its shape, its gravitational and magnetic fields, and its internalnstructure) and a meteorologist (a scientist who studies climate andnweather).

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nWegenernproposed continental drift in 1912. He’d noticed that the continentsnseemed as if they fit together like a jigsaw puzzle, He studied rocknformations and fossils in the matching sides of the continents, andnhe found a lot of evidence to back up his idea that they were oncenjoined together. He even came up with the idea that the Mid-AtlanticnRidge was a place in which the Atlantic Ocean was spreading, as henput it, “continuously tearing open and making space for fresh,nrelatively fluid and hot” rock rising from the Earth’s interior. n

Wennow know that Wegener was right! The continents once werenglommed together in one huge mass we call Pangea (from the Greek, forn“all-lands”). And the Mid-Atlantic Ridge isnformednbyncontinuous seafloor spreading and upwelling of fresh magma. n

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nHowever,nin 1912, nobody could come up with ideas of how this could possiblynhappen, so mosts scientists did the sensible thing: They werenskeptical of Wegener’s theory. (Some scientists even forcefullynattacked the idea of continental drift and promoted “permanentist”nviews that the continents have always been permanently in the placesnthey are now.)

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nHowever,ndecades later, in the 1950s, paleomagnetic data wasndiscovered—information about Earth’s magnetic fields recorded innancient rocks. Long story short, this new data joined the geologicnand fossil evidence in favor of continental drift.

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nSonmost scientists did the sensible thing: They changed their minds. Bynthe 1960s, Wegener was recognized as a founding father of the newnscience of plate tectonics.

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nAsnalways, I am impressed by both the initial skepticism and the laternacceptance of this radical, counter-intuitive idea. Becausenscientists demonstrated that they don’t accept any cool soundingnidea, just willy nilly—they look for a cause or mechanism, theynlook for more evidence. However, scientists also demonstrated thatnthey don’t cling to old ideas “just ‘cuz.” When the “morenevidence” arrives, they can accept the new idea. This is whynscience and scientific thinking are the best ways to find out aboutnreality!

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nFornmore on continental drift and lots of cool links to websites andnanimations, see this earlier post.

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