The Distance of the Moon
At one time, according to Sir George H. Darwin, the Moon was very close to the Earth. Then the tides gradually pushed her far away: the tides that the Moon herself causes in the Earth's waters, where the Earth slowly loses energy.
Before forming its atmosphere and its oceans, the Earth must have resembled a grey ball revolving in space. As the moon does now; where the ultraviolet rays radiated by the Sun arrive directly, all colors are destroyed, which is why the cliffs of the lunar surface, instead of being colored like Earth's, are of a dead, uniform grey. If the Earth displays a varicolored countenance, it is thanks to the atmosphere, which filters that murderous light.
Games Without End
When the galaxies become more remote, the rarefaction of the universe is compensated for by the formation of further galaxies composed of newly created matter. To maintain a stable median density of of the universe it is sufficient to create a hydrogen atom every 250 million years for 40 cubic centimeters of expanding space. (This steady state theory, as it is known, has been opposed to the other hypothesis, that the universe was born at a precise moment as the result of a gigantic explosion.)
Situated in the external zone of the Milky Way, the Sun takes about two hundred million years to make a complete revolution of the galaxy.