Supercontinent: Ten Billion Years in the Life of Our Planet (20 page)

One geologist of whom we shall hear more later has already
suggested
, on the strength of this paper, that we should name the Supercontinent Cycle the ‘Sutton Cycle’. He is Professor Mark McMenamin, of Mount Holyoke College, Massachusetts, who like Sutton forms one half (with Dianna McMenamin) of a connubial scientific partnership. But this coincidence serves to remind us of a
problem peculiar to the older team, which might scupper the chances of the term ‘Sutton Cycle’ gaining widespread acceptance.

Just as it is hard to see the join between the work of unrelated
scientists
in the collective activity of science, it is nigh impossible to separate the work of John Sutton from that of his brilliant wife, Janet Watson. Just about everything they did, whether acknowledged in authorship or not, was done together. John’s energy, ambition and drive, and Janet’s daunting clarity of thought, complemented each other perfectly. Neither would have done the work they did without the other, and there is undoubtedly as much of Janet as of John in the great 1962 paper.

Despite the fact that Janet not only joined her husband as a Fellow of the Royal Society but also became President of the Geological Society of London (something John never achieved), there is a fairly widespread belief that Janet Watson still languishes unjustifiably in the shadow of her powerful husband. Today the gender politics
surrounding
the scientific legacy of Sutton and Watson is every bit as delicate as that of the Cold War. Naming the Supercontinent Cycle for Sutton alone would not be popular in many quarters; but leaving that aside, the case is a strong one. But there may be an even stronger one.

Like Wegener, Sutton had observed a pattern that cried out for a mechanism. Finding out
what
happened in Earth history is step one in geology; the next step is a search for the
reason
it happened. Why should mountain building be cyclic? Radioactivity, the discovery that gave Earth science both a clock to measure the Earth’s age and a mechanism to explain why the planet did not just cool down and die, provided Sutton with the mechanism.

But that idea was neither his, nor Janet Watson’s. Moreover, it was the oldest of all, having first appeared in the literature in 1924,
waiting
for its moment to join, in the right way, with another set of ideas, and finally make new sense.

Trinity College, Dublin, founded by Queen Elizabeth I in 1592, has a tradition of supporting individualistic thinkers. Within its grey
granite
walls three things came together: long-standing interest in the age of the Earth, the new discovery of radioactivity and John Joly.

One of Trinity’s very first graduates was James Ussher (1581–1656), Archbishop of Armagh and Primate of Ireland. Ussher was a versatile scholar, who set himself the task of analysing
astronomical
cycles, historical accounts and several sources of biblical chronology, to determine the precise date on which his God had
created
the Earth. His timetable of creation,
Annales Veteris Testamenti,
was first published in 1650; but in 1701 it was incorporated into the authorized Bible, and from that time the Archbishop’s calculations came to be seen by believers in much the same dim, religious light.

Although today most people who have heard of Ussher know only about his dating of the Creation to the evening preceding Sunday 23 October 4004 BC, Ussher’s project did not rest on the seventh day. After succeeding in his main task the indefatigable Archbishop went on to date other biblical events as well. Adam and Eve, he decided, were driven from Paradise on Monday 10 November that same year, and Noah’s ark alighted on the summit of Mount Ararat on 5 May 1491
BC
(a Wednesday, apparently).

It is far too easy to laugh at the good Archbishop and his pedantic prose today, not to mention the full English title of his work (1658), which reads:
The Annals of the World Deduced from the Origin of Time, and continued to the beginning of the Emperour Vespasians Reign, and the totall Destruction and Abolition of the Temple and Common-wealth of the Jews. Containing the Historie of the Old and New Testament, with that of the Macchabees. Also the most Memorable Affairs of Asia and Egypt, and the Rise of the Empire of the Roman Caesars, under C. Julius, and Octavianus. Collected from all History, as well Sacred
, as
Prophane, and Methodically digested, by the most Reverend James Ussher, Archbishop of Armagh, and Primate of Ireland.

We do not need, after reading that, to go into the details of Ussher’s calculations. Clearly this was a serious scholarly attempt, according to the ruling beliefs of his time, to consult the records of many cultures and answer a nagging question that has only been finally determined by science in the past sixty years.

This question of the age of the Earth was next taken up at Trinity by Samuel Haughton (1821–97), Professor of Geology from 1851, who tried to estimate the Earth’s age by adding up thicknesses of
sedimentary
strata in the belief that their maximum observed thicknesses would turn out to be proportional to the time it took to deposit them. His immensely laborious arithmetic came out with an Earth age of 200 million years, a figure that then seemed so large he scarcely believed it himself. However, his method depended on so many assumptions about rates of deposition in different kinds of rock that you could, by tweaking the sums a bit, obtain almost any answer you wanted. This did not discourage scientists from trying, and Haughton’s work was continued by another Trinity professor, William J. Sollas (the eccentric father of Hertha Sollas, who translated Eduard Suess’s great book into English). However, it fell to Sollas’s successor, the great Irish geophysicist John Joly (1857–1933), at last to make progress in tackling Kelvin on his own terms.

John Joly claimed descent from a line of King’s counsellors at the French court dating from as far back as the fifteenth century. His mother went by the title of Julia Anna Maria Georgiana, Comtesse de Lussi. But Joly’s father, who died not long after his youngest son was born, lived modestly as a simple country vicar in County Offaly.

Contemporary cartoon of John Joly.

 

Joly was a remarkable all-round intellectual who made important
scientific
contributions in geology and physics. But, along the way, he also found the time to take first-class honours in modern literature, to invent the first single-plate colour photographic process, to pioneer the use of radium in cancer treatment, devise new navigational techniques and to write poetry, including sonnets on scientific themes, many of which are much better than merely competent. Like du Toit, he rode a motorcycle and also sailed. Joly was a popular man, with his pince-nez, swept-back hair, walrus moustache and rolled r’s (an affectation he thought helped to disguise a slight lisp; though many wrongly imagined it was a French accent) and he cut a tall, dapper, even roguish figure among the Trinity dons. He was not without his eccentricities either, notable among which was his habit of wearing a radioactive hat to see if he could detect the effect of gamma rays on his memory.

Joly’s was a restless and wide-ranging mind. Like many a don
before and since, and despite developing a taste for world travel, he gave Trinity College his life; never marrying, but maintaining an intense long-term friendship with his opposite number in the Department of Botany, Professor Henry Horatio Dixon. Joly worked with the younger scientist on botanical problems, and they are now for ever coupled in the annals of botany for being the first to work out, in 1895, how sap rises. The two men lived close to each other in suburban Dublin, and are today even united in death. Ignoring his friend’s wish to be buried in his native Offaly, Dixon had Joly buried in Mount Jerome Cemetery, Dublin, not far from Trinity.

Though a brilliant technical scientist, at his best when solving
problems
by devising cunning pieces of equipment, Joly seems to have been a little naive. Like many patriotic men of science with some knowledge of the sea, he wrote letters to the Admiralty on the
outbreak
of war, one of his ideas being to reduce submarine attacks on British merchant ships by building all British ships in the shape of German submarines. However, like Eduard Suess, Joly was no
armchair
general and was not above taking to the barricades.

On Easter Sunday 1916 Joly, armed with a Lee Enfield rifle, helped to secure his beloved College against the Uprising that was then raging through the city outside. It was a tense time. By Monday, 2000 Nationalists had taken up strategic positions and their leaders had proclaimed an Irish Republic; but the Uprising lasted only a few days before its leaders surrendered. Fifteen of them were executed and up to 3000 more were interned.

Joly put away his rifle, though his Loyalist sympathies remained with him and deceived him badly. As a futurologist he proved no more successful than Lord Kelvin had been, when he predicted that the Nationalists would never succeed in gaining independence from Britain. Only five years later the Irish Free State was established.

Although Trinity first employed Joly as an assistant to the professor of engineering, and then to the professor of natural philosophy, Joly turned increasingly towards geology and used his own colour photographic process (which he patented in 1894) to
produce
the first colour pictures of minerals in thin section under the microscope. It was following this work, in 1897, that he bid
successfully
for the vacant Chair of Geology and Mineralogy. He held the job for the rest of his days, and healing the divide between his two main loves – geology and physics – became a lifelong mission. The age of the Earth was too large a question, and too wrapped in Trinity’s academic tradition, for him to ignore.

In 1840 mysterious markings had been discovered on some rocks at Bray Head in County Wicklow: marks evidently made by the feeding activity of some long-vanished organism. The trace fossil was called
Oldhamia
, after the very same Thomas Oldham we have met before in India, but who took up that colonial post with the Indian Survey after serving as Professor of Geology at Trinity.

Joly wrote a sonnet to this humble trace, and Dr Patrick Wyse Jackson, who is today curator of Trinity’s Geological Museum and an expert on Joly’s life and work, believes that it betrays Joly’s special feeling for the immensity of geological time.

Joly, like many a geologist before and since, grew a little giddy
staring
into the abyss of time, but the uneasy truce over the depth of that abyss finally collapsed when Kelvin revised his estimate of the Earth’s age downwards from 100 million to twenty million years. Joly knew there could now be no reconciling Kelvin’s conclusions with
geologists’
gut feeling that the planet simply had too much recorded history to be squeezed into such a short span. Joly attempted to find another way; to search for a different quantitative approach, whose
conclusions
were not (like Haughton’s) open to such differing interpretation, and which could offer a more probing test of Kelvin’s conclusions. Independently, he hit on an idea first suggested by Edmond Halley (1656–1742), the first man to predict the return of the comet named after him.

Halley had had different motives from Joly. Although Halley also wanted to expand the amount of time available for geological processes (he was looking for a few thousand years extra), his other objective had been to refute a different, to his mind more dangerous (and much older), idea: namely, that the world was eternal. Halley was not simply trying to burst bonds imposed by Christian dogma but, within that framework, to refute the Greek philosopher Aristotle’s idea of an ahistoric, eternal Earth. Aristotle’s world without beginning or end, oddly reminiscent of Hutton’s
nineteenth-century
version (‘no vestige of a beginning, no prospect of an end’) had always offended Christian tradition, because (to use Archbishop Ussher’s words) it ‘spoileth God of the glory of His creation’.

Just as Kelvin’s method was based on two central assumptions – that the Earth was cooling down from an original molten mass, and that no new heat had been added since – Halley’s and Joly’s idea
presumed that the Earth’s first ocean had been freshwater, and that all the salt now dissolved in it got there by being washed off the land. If Joly could find out four things – the volume of the ocean, the average concentration of salt in it, the amount of water coming down all the Earth’s rivers, and the amount of salt contained in that – then he would have all the information needed to calculate how long it had taken for the rivers to put
all
the salt into the ocean, and thus discover the age of the Earth.