Geology Reference
In-Depth Information
the result of dedicated hard work over many years of consider-
able trial and much error. The combined talents of these two
great scientists - the fastidious care with which Nier performed
his analyses, and, with good data to hand, Holmes' ability to
think deeply about the great geological problems of his day -
eventually provided us with a means whereby the age of Mother
Earth could at last be deduced. As yet, they had not got that age
right, but everything was in place - the basic technology to
obtain the data and a model to calculate the results. All that
remained now was to improve the machine and find the right
samples to work on.
But as usual, not everyone liked the idea of an ever more
ancient planet. It seemed to some that just as they were getting
used to the idea of the Earth being a certain age, then up it would
go again, requiring them to once more readjust all their pre-
conceived ideas. A typical reaction was as follows:
We must congratulate him
[Holmes]
on having again advanced our
knowledge of geological ages by a marked achievement. But I believe it
should be emphasized that what has been ascertained is not, as Holmes
states, the 'age of the earth', but the 'age of the materials forming the
earth'. Our conceptions of the birth of the solar system and the earth are
vague, but in current opinion the zero time that Holmes has determined
would not apply to the earth but to some earlier event, that for conven-
ience might be called the birth of the Milky Way. The subsequent for-
mation of the earth as a separate entity came later and there is no reason
for supposing that the clock Holmes has read for us, was set to zero again
by that revolution. Hence, the earth is younger than 3,000 million years.
The di¬erence need be only a small amount, but it may also amount to
a large fraction of the estimated age.
I hope this remark will serve to clarify a minor point in an otherwise
lucid and epoch-making contribution from the great time keeper among
geologists.
Holmes was slightly indignant:
'I had not overlooked the
fundamental distinction to which Professor Kuenen directs
attention'
, and went on to clarify his reasoning.
'It is generally
