Suppose that this catastrophe were to take place. Would that be the end of all things? No. Out of the fiery mist many millions of miles across--like one of those great nebulæ which the telescopes reveal to us--order would be evolved. Two things would at once begin to happen, since in the Universe nothing stands still. The fiery mist would be giving out heat all about it, sending out heat-waves as a fire or a red-hot poker will do. The red-hot poker cools; so, too, would the fiery nebula. Then the nebula would begin to condense; not quite in the same way that a cloud of steam does, for it would be whirling all the time, and its fiery particles would be all trying to fall inwards, just as anything dropped from our hands tends to fall towards the centre of the earth. As this whirling mass of gas condensed some great masses of it would become detached, and would begin to enjoy separate existences of their own. Let us imagine, for the sake of argument, that a mass of gas vast enough, when it condensed, to form the earth itself became detached from the parent nebula. Suppose we follow its history. At first it may have been a globe hardly distinguishable from a whirling flame. In brightness it was like the Sun, and like the Sun, it was covered with elemental gases. It was, in fact, in its earliest days a sphere of gas continually giving out heat, and continually cooling, till from a sphere like the Sun it became a ball like Jupiter. It had an intermediate stage when its gases were condensing into liquids, as steam condenses into water; for though the nebula as a whole was hot it was always travelling through cold space. Gradually the earth became partly liquid and partly gas. For millions of years it continued to revolve as a ball of liquid--still cooling--still being pressed very hard at its central parts by the weight of all the gases and liquids round it, till at last the first crust of solid matter began to form on the liquid surface. This crust continued to thicken, but it was subject to many appalling catastrophes and breakages. We have already used the occurrence of the tides of the earth as an instance of the Sun's attraction. The Sun (and the Moon) attract the waters of the earth, pulling them up towards themselves. So would they also attract the molten materials of which the early earth was composed. The liquid mass would be continually surging like a tide against its wall of solid crust, and the liquid would now and again burst through. There must have been a time when the thin solid crust covering the molten interior became, owing to the solidification and contraction of the crust, much too small to contain the liquid material. The lava would then break through, and would form huge craters, not unlike some of those which we see on the Moon. We can faintly imagine these terrible outbreaks in which the molten tide rose not thirty or forty feet but many miles high!