Wegener — Right, and Refused

The first five articles all ran the same way: why a wrong theory was plausible, and what it left. This last one runs the other way.

A world in which land does not move

Begin with what geology was at the start of the twentieth century.

The geology of Hutton and Lyell was a great achievement: the Earth is immensely old, and mountains and canyons can be accounted for by the slow processes visible now, without invoking a Flood.

What he assembled

In 1912 a thirty-one-year-old meteorologist named Alfred Wegener announced that the continents move. He offered more than the shape of the map.

1. Fit them not at the coastlines but at the submerged edges of the continental shelves and the match is far better.
2. Strata and mountain ranges run on across the gap. South African beds continue in Brazil; the Appalachians continue in Scotland.
3. The same fossils appear on both sides. Mesosaurus was a freshwater reptile found only in Brazil and southern Africa — an animal that could not cross an ocean. The seeds of the plant Glossopteris are the same case.
4. The ancient climates do not fit. India, Australia and southern Africa carry glacial scars from the same period, though they now lie near the equator. And there is coal in Antarctica.

But he had no engine

Here is the heart of it. What pushed the continents? Wegener offered two things: a force driving bodies away from the poles, and the tides raised by the moon and sun.

The British geophysicist Harold Jeffreys did the sums.

And the part that was unfair

Yet something in the manner of the refusal is not accounted for by that.

Wegener was a meteorologist, not a geologist — an outsider entering another discipline.

At a symposium in New York in 1926 his theory met near-unanimous opposition. The record shows remarks that pass beyond scholarly objection into ridicule, including the sentiment that if continents were allowed to float freely, geology would have to begin again from nothing.

A little further in

The engine was arriving elsewhere

The first piece of the answer existed before Wegener published. Nobody had connected it to geology.

Radioactivity, which changed two things about the Earth at once.

1. Kelvin had put the Earth's age at twenty to a hundred million years, calculating how long it takes to cool. That calculation assumed no internal heat source. Radioactive decay is one, and with it the age became four and a half billion years.
2. That heat has to go somewhere. In 1929 Arthur Holmes proposed that it could drive very slow convection in the mantle — not a force pushing continents but a current carrying them.

Hunting submarines, finding a ridge

Detecting submarines drove the development of echo sounding and shipborne magnetic survey. When the war ended, that equipment began mapping the ocean floor.

What emerged was a landscape nobody had predicted.

1. A vast submarine mountain range runs down the middle of the oceans, circling the globe.
2. A rift valley splits its crest, and earthquakes follow that line.
3. The rocks of the sea floor are astonishingly young. Nowhere is the sea floor older than two hundred million years, while continents carry rocks four billion years old.
4. The floor ages regularly with distance from the ridge.

Stripes that mirror each other

The decisive confirmation came from Vine and Matthews in 1963, and it is the cleanest case of prediction and test in this whole series.

The Earth's magnetic field reverses every few hundred thousand years, and rock freezing at a ridge records the direction prevailing at the time.

The picture was right and the engine was wrong

So the story does not end with 'Wegener was right'.

Wegener did not see the ending. He died in November 1930 on the return journey from resupplying an inland station in Greenland, the day after his fiftieth birthday. His body was found in the snow six months later.

The discipline conceded that he had been right thirty-three years afterwards.

Was it wrong to demand a mechanism?

This is the part to be careful with. Ending the story as 'a stubborn establishment failed to recognise genius' is comfortable, and it would demolish the standard this series set in the previous article.

What the six articles leave

One last count, to close the series: what actually brought these theories down?

1. Phlogistona balance — weighing everything, vessel and air included
2. The aetheran interferometer — setting light against light instead of timing it
3. GeocentrismTycho's data and Kepler's eight minutes — observation too precise to wave away
4. Galena knife held in one's own hand, and Harvey's arithmetic
5. Lamarcknine hundred mouse tails, and then the gene
6. Wegenera magnetometer dragged across the sea floor — built to hunt submarines

1. 1788Hutton — deep time, and a wariness of catastrophes
2. 1898Curie — radioactivity, answering the Earth's age and its internal heat
3. 1912Wegener — publishes continental drift
4. 1924Jeffreys — calculates that tidal forces cannot do it
5. 1926The New York symposium — near-unanimous rejection
6. 1929Holmes — proposes mantle convection
7. 1930Wegener dies in Greenland
8. 1962Hess — sea-floor spreading
9. 1963Vine and Matthews — confirmation by symmetrical magnetic stripes

The question that remainsSomewhere now there is a claim with the evidence piled up and no known mechanism. And there are far more claims, with neither, that compare themselves to Wegener. The second is very easy to make look like the first. On what, then, should we separate them?