The Sun and the Moon
Will the World Become Like the Moon?
Our earth will probably become like the moon. There will be certain differences, because the earth is much larger than the moon. The moon has been too small to hold to itself the gases outside it. It has no air, or atmosphere. The earth is able to keep its atmosphere because it is bigger, and so the power of its attraction is much greater. Besides, the earth makes some heat of itself, though not very much, probably.
Another difference is that, in consequence of the rapid cooling of the moon, the changes on its surface have been more violent than those on the earth. The biggest volcano on the earth is as nothing compared with the moon’s. But all these points of difference do not affect the fact that our earth is likely some day, though after a long, long time, to become cold and lifeless.
Does the Sun Move or Does it Stand Still?
The sun has two movements. Like the earth, the sun spins, or rotates, upon itself, and in the same direction as the earth. Thus. we can notice a sun-spot appear at one side of the sun, travel across its face, disappear for scveral days, and then reappear where we saw it first.
Besides this movement of rotation, the sun has a movement of translation, as it is called - that is, an actual bodily movement from place to place. We do not doubt that all other stars are in motion too. It used to be impossible to see any sort or arrangement or order in the movements of the sun and the other stars; but a Dutch astronomer, Professor Kapteyn, and others following him seem to have shown that the stars consist of two great hosts which are streaming through or past each other in opposite directions and at different speeds; and they think that our sun belongs to one of these groups of stars. There may be more than two groups, or galaxies. Of course, where the sun moves he carries all his family with him - planets, moons, comets, and so on, together with everything that is born and borne upon them; but neither astronomer nor other scientist can say where the sun is carrying us nor what the result will some day be.
