UNDISCOVERED WORLDS

Wanganui Chronicle, Volume LXXXIII, Issue 19722, 13 December 1926, Page 11

UNDISCOVERED WORLDS

SOUGHT BY ASTRONOMERS BETWEEN MERCURY AND SUN Is there an undiscovered planet between Mercury and the sun? Many astronomers believe there is. Yet it has never been seen. Such a planet, being so close to the sun, would be imperceptible (states J. A. Lloyd, F.R.A.S., in the “Daily Mail”)- Mercury itself is most difficult to see except on I'are occasions. Even then we must know where to look. But so sure are some astronomers of the existence of this unknown planet that they have given it a name. They call it “Vulcan.’’ There are several ways in which it might be discovered. The mathematician, Lc Verrier, hoped that a study of the movements of Mercury would reveal it. Yet, though he found irregularities in the movements of Mercury which pointed to the disturbing influence of this hypothetical planet, he was unable to lay his hands on it. But a body revolving between the earth and the sun must sometimes cross the. disc of the latter as h. dark spot. Mercury and Venus both “transit” in this way, and their times of doing so arc known with great accuracy. Le Verrier calculated the probable of Vulcan and the probable date of its next transit across the sun’s disc. Everyone kept tin eye on the sun for the new planet. Nothing, however, was seen. It is true that black spots have been observed crossing the sun's disc on several occasions. Whether one of these was Vulcan is not certain. Between the orbits of Mars and Jupiter there is a wide zone occupied by a vast number of minor planets or “asteroids.” About 1000 of these little bodies have been found. Since the systematic photographic survey of the heavens by our leading observatories has been in operation, every year has added to the number of asteroids. Yet many more remain to be discovered.

Everyone knows that the planet Neptune, which marks the boundary of the solar system as we know it, was discovered by mathematics. Certain irregularities in the movements of Uranus suggested the existence of an unknown planet influencing it. A careful (analysis of these irregularities led to the discovery of Neptune, which was actually found in the exact position in the heavens that the mathematicians had indicated. Tn the same way irregularities in Neptune’s motion have led nffiny astronomers to suspect the presence of an unknown planet still farther away. Indeed, there is reason to believe that there arc at least throe undiscovered planets farther off tiffin Neptune.