MESSAGES TO MARS.

Manawatu Times, Volume XLVII, Issue 2762, 2 October 1923, Page 2

MESSAGES TO MARS.

LIGHT SIGNALS IMPOSSIBLE. Astronomers in England have again been discussing the possibility of sending messages to Mars. Unfortunately, remarks one authority, tho one method suggested as the most favourable—.that of .light signals—is of all the methods, proposed, Hie most impossible; and if thorn wera any chance of its success it would certainly not be when Mars is nearest the earth. Jt would, at first sight, seem that, as Mars.is so magnificent an object in the night; sky when it is nearest the earth, which is seven times bigger, ought then to he a much more splendid spectacle in the night sky of the Martians. But actually at the time out' planet is quite invisible to the hypothetical Martians, for it is then broad daylight on the Martian hemisphere turned earthwards, and an observer on .Mars could only see the earth if it were artificially illuminated on every square mile of its surface by a light more powerful than sunlight. If it were possible to, make a light, or mirror to rcfiocf the sunlight, with an area of at least 2000 square miles it might just be seen from Mars by means of a very powerful telescope. But these signals would only be possible when Mars, seen from the earth, is about 80 degrees from the sun, and the earth, seen from Mars a thin crescent, visible for a few minutes before sunrise and after sunset on Mars. There is more hope of reaching Mars by aeroplane than of getting into communi. cation with its supposed supermen by any method of signalling which depends on light to carry onr greetings, far a halfpenny thirty miles away would be bigger than a terrestrial "spot" of light 2000 square miles in area would be to the Martian? in a giant tolescops, the smallest light signal they could possibly see.