The gospel of evolution / by Professor J. Arthur Thomson.

  • Thomson, J. Arthur (John Arthur), 1861-1933.
Date:
[1925]
Catalogue details

Licence: In copyright

Credit: The gospel of evolution / by Professor J. Arthur Thomson. Source: Wellcome Collection.

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    were drawn out the arms of an enormous spiral nebula. After the nebulous fiery birth and the receding of the anonymous passing parent, the great arms of the spiral nebula—less, however, than i per cent, of the sun’s mass—developed knots or nuclei. Four small knots became the cores of the four inner planets. Nearer to the sun than the earth is, arose Venus and Mercury ; and further away was Mars. Beyond Mars came the zone of the small planetoids and the planetesimal dust ; and outside this were four greater knots, the beginnings of the major planets, namely, Jupiter, Saturn, Uranus, and Neptune. THE GROWTH OF THE EARTH. It has been calculated that the newborn earth—the “ earth-knot ” of Chamberlin’s theory —had a diameter of about 5,500 miles. But it grew by drawing planetesimals into itself until it had a diameter of over 8,100 miles at the end of its growing period. Since then it has shrunk, by periodic shrinkages which have meant the buckling up of successive series of mountains, and it has now a diameter of 7,918 miles. But during the shrinking the earth became more varied. A sort of slow boiling of the internally hot C.E. D