Discussions on climate and cosmology / by James Croll.

  • James Croll
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: Discussions on climate and cosmology / by James Croll. Source: Wellcome Collection.

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    should have what Professor Tait has suggested, a nebula consisting of clouds of stones. But such nebulae must be of rare occurrence. Objections considered.—On a former occasion I con- sidered one or two anticipated objections to the theory that stellar light and heat were derived from motion in space. But as these objections have since been repeatedly urged by physicists both in this country and in America, I shall again briefly refer to them. Objection 1st. The existence of such non-luminous bodies as the theory assumes is purely conjectural, as no such bodies have ever been observed. In reply, it is just as legitimate an inference that there are bodies in stellar space not luminous as that there are luminous bodies in space not visible. We have just as good evidence for believing in the existence of the one as we have in the existence of the other. Bodies in stellar space can only be known through the eye to exist. If they are not luminous, they of course cannot be seen. But we are not warranted on that account to suppose that they do not exist, any more than we have to suppose that stars do not exist which are beyond the reach of our vision. We have, however, positive evidence that there are bodies in space non- luminous, as the meteorites and planets for example. The stars are beyond doubt suns like our own; and we cannot avoid the inference that, like our sun, they are surrounded by planets. If so, then we have to admit that there are far more bodies in stellar space non-luminous than luminous. But this is not all: the stars no more than our sun can have been dissipating their light and heat during all past ages; their light and heat must have had a beginning; and before that they could not be luminous. Neither can they con- tinue to give out light and heat eternally; conse-