Fig. 39.—The Earth viewed from Venus.
When we contemplate this radiant Venus, it is difficult, even if we can not form any definite idea as to her actual state as regards habitation, to assume that she must be a dreary desert, and not, on the contrary, to hail in her a celestial land, differing more or less from our own dwelling-place, travailing with her sisters in the accomplishment of the general plan of Nature.
Such are the characteristic features of our celestial neighbor. In quitting her, we reach the Earth, which comes immediately next her in order of distance, 149 million kilometers (93,000,000 miles) from the Sun, but as we shall devote an entire chapter to our own planet, we will not halt at this point, but cross in one step the distance that separates Mars from Venus.
Let us only remark in passing, that our planet is the largest of the four spheres adjacent to the Sun. Here are their comparative diameters:
| The Earth = 1. | In Kilometers. | In Miles. | |
| Mercury | 0.373 | 4,750 | 2,946 |
| Venus | 0.999 | 12,730 | 7,894 |
| Earth | 1.000 | 12,742 | 7,926 |
| Mars | 0.528 | 6,728 | 4,172 |
It will be seen that Venus is almost identical with the Earth.
MARS
Two hundred and twenty-six millions of kilometers (140,000,000 miles) from the Sun is the planet Mars, gravitating in an orbit exterior to that which the Earth takes annually round the same center.