Alfred Wegener presented hypothesis of continental drift - January 6, 1912

On this day in 1912, German geophysicist and meteorologist Alfred Wegener first presented his hypothesis on continental drift in a public lecture.

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Episode Transcript

Speaker 1 (00:00):
This Day in History Class. It's a production of I
Heart Radio. Hey everyone, welcome to the podcast. I'm Eves
and you're listening to This Day in History Class, a
podcast that really takes to heart the phrase you learn
something new every day. Today is January six. The day

(00:26):
was January six, nineteen twelves. German geophysicist and meteorologist Alfred
Wegner first presented his hypothesis on continental drift in a
public lecture. Wagner advanced the hypothesis of continental drift, but
he was not the first to propose that continents gradually
drifted across Earth's surface. Wagner's hypothesis was largely rejected by

(00:51):
the scientific community, but it did influence the development of
the theory of plate tectonics. For centuries, people have record
noyes that the coastlines of the continents could fit together
as if they were puzzle pieces. Wagner recognized this, and
around nineteen ten he became interested in looking into the
reason behind the observation. He came across the idea that

(01:15):
Africa and South America were once connected by a huge
land bridge. He also read about the similarities between fossils
on different continents and he noticed that Greenland had drifted
away from Europe, and that San Diego and Shanghai we're
getting closer to one another over the years. Geological features
also matched each other when continents were brought together, but

(01:38):
he rejected the idea that land bridges between continents just
sank and disappeared. After reading about other lengths between continents,
Wagner became convinced that all the continents were once joined
as a single continent. The lecture he presented on January sixth,
nineteen twelve, at a meeting of the Geological Association in
Frankfurt was called the Uprising of Large Features of Earth's crust,

(02:02):
Continents and Oceans on geophysical basis. Three years later he
published the book The Origin of Continents and Oceans. He
proposed that there was one big or continent surrounded by
a global ocean. According to his hypothesis, the massive continent
began to split about two hundred million years ago, and

(02:23):
the newly formed continents never stopped drifting apart. He called
this movement continental displacement. He turned to fossils, geologic evidence,
and climatology to support continental drift, but people largely opposed
the idea. That was partly because Wagner did not have
a good model for how the continents moved apart. He

(02:45):
suggested that gravitational pool and centrifugal entitled forces moved the
continents through Earth's crust, but that was an unbelievable proposal.
If continents plowed through the oceanic crust, then they would
be distorted, and centrifugal entitle forces were likely too weak
to move continents. There was no direct evidence at the

(03:06):
time for the movement of the continents, and there was
no known mechanism that would be able to move entire continents.
On top of this, Wagner miscalculated the rate at which
North America and Europe were moving apart. Though some people
supported his explanation, most geologists stuck to the hypothesis of
static continents and land bridges. Wagner died in nineteen thirty.

(03:30):
It wasn't until the nineteen fifties when scientists returned to
the theory of continental drift as they explored the ocean floor.
Wagner's hypothesis wasn't completely off. For instance, continental movement did
have a hand in the creation of mountains, just not
as he suggested. Now. Plate tectonics is the most widely

(03:50):
accepted theory. It says that Earth's crust is split into
rigid moving plates that move slowly over the underlying mantle.
While the continent do move, as Wagner and others before
him proposed, so does the oceanic crust. The driving force
for the motion is likely conviction currents and the magma
of the upper mantle. I'm Eave Jeff Coote, and hopefully

(04:13):
you know a little more about history today than you
did it yesterday. You can find us on social media
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and have a fantastic twenty four hours until we see

(04:36):
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