EARTH AND MOON.

Auckland Star, Volume LIII, Issue 103, 3 May 1922, Page 9

EARTH AND MOON.

(To the Editor.} Sir,- Mr. Kelly's interesting article about the probable reunion of the earth ■and moon might lead people to suppose that the moon is in unstable equilibrium and liable at any time to either fall to the earth or shoot off into space. But it is not so; it is no more unstable j than a pendulum, which tends to return | to its central position more strongly, ] the further it is pushed away. At every revolution around the earth, the moon does come hundreds of miles nearer to us than its average distance, but its speed is so much greater then that the increased centrifugal force drives it to its farthest position again. If it did fall upon the earth the result would be more of a smash than Mr. Kelly states, for the shell of the earth, surrounding the liquid interior, is no thicker in proportion than that of an egg. Before the moon separated from the earth, the material of which they are composed was diffused through a space much larger than the orbit of the moon, and because it was not absolutely spherical it consolidated into two globes instead of one.—l am, etc., J.M.