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?LUMINOUS SPIRAL CLOUDS OF MATTER?
(Nebula photographed 1910)
Photo: G. W. Ritchey
About the earth circles a smaller sphere, the moon, at an average distance of 239,000 miles. Earth and moon are not the only bodies to travel round the sun. There are also the planets, Mercury and Venus, at distances of thirty-six and sixty-seven millions of miles; and beyond the circle of the earth and disregarding a belt of numerous smaller bodies, the planetoids, there are Mars, Jupiter, Saturn, Uranus and Neptune at mean distances of 141, 483, 886, 1,782, and 1,793 millions of miles respectively. These figures in {3} millions of miles are very difficult for the mind to grasp. It may help the reader?s imagination if we reduce the sun and planets to a smaller, more conceivable scale.
