“Again, to bring the argument nearer home, to our own system, Mercury is nearest the sun, at a distance of but 36 million miles, or thereabouts, and in order of distance follow Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, etc., the most distant measured being Neptune at 2794 million miles away—there are many others of equal bulk further off still, but these will answer my purpose;—now if the planets, and the stars that are not suns _cannot_ give their own light, what lights them? And again, if these members of our system are _entirely_ dependent on this governing sun for every particle of their light, it would naturally follow that Mercury, being nearest the sun, would be brightest, and then the others in proportion to their distance; but we have the second star, Venus, as the brightest star in the whole system; the next brightest is not Earth, as we should expect (for we saw in coming that Mars, who is distant from the sun over half as far again as is Earth, was considerably brighter than Earth), but Jupiter, the _fifth_ in point of distance; yet Jupiter, from a scientific and theoretical point of view, can only receive about twenty-five or twenty-six times _less_ light from the sun than do we on Earth; Saturn over eighty times less, Uranus a shade over a three hundred and sixtieth part, and Neptune barely a one-thousandth part of Earth-light and -heat! “Many theories have been propounded to account for this, the most popular being that the differences in lighting are merely those of atmosphere. That, however, will not bear argument, because modern science has proved positively what has been for ages asserted—that we can live on Mars and Venus, and so far as atmosphere goes we could live on Mercury; yet if the argument is to stand we should be burnt up on Venus and roasted alive on Mercury, which is so near the great heat of the sun that it should itself be a star, a subsidiary red-hot sun. To carry the same argument further, we ought not to be able to see Neptune at all, considering his great distance and the little light he receives from our sun, for if he depended on that alone, he would be quite invisible to us. And to take it still further, to the planets discovered far beyond the orbit of Neptune and yet undoubtedly belonging to our system: how did they get there? and why were they not noticed, as belonging to our system, before the nineteenth to twenty-first centuries. If flung from our sun ages before, they would have wrecked the whole system, being great masses of energising matter, and at their enormous distances they cannot possibly receive any appreciable light from the sun, which will be but a star to them. Yet we can see them plainly, when by the very argument brought forward, of the sun being sole light-giver, they should be black and altogether invisible. No, Spenser, they must have been attracted and are now kept within the sun’s mighty influence by his power, but receive not his light.