THE SKIES OF VENUS

Southland Times, Issue 19523, 24 May 1922, Page 3

THE SKIES OF VENUS

DO THEY SHELTER LIFE ? Whether life, as we understand it, can exist elsewhere in the universe has often been a subject of controversy (writes the Astronomical correspondent of the London Morning Post). In the Solar system, at any rate, it seems probable that for the most part .planetary conditions are quite unsuitable for a race of beings physiologically similar to ourselves. It has, however, been argued that, of the planets of the Solar system it is not the much discussed Mars, but Venus that is likely to provide the nearest approach to terrestrial conditions. It is still quite uncertain how long the “day” of Venus is. It may be about equal to our own, or on the other hand it may always keep the same face to the sun, as our moon always keeps the same face towards the earth, except for small oscillations. A third alternative has recently been suggested by Professor Pickering, who thinks he has found evidence of a period of nearly three of our days. THE THREE THEORIES We can hardly conceive existence under perpetual sunshine or perpetual darkness, so that we need not envy any possible inhabitants of Venus if the second hypothesis be the true one, however much the probable cloudiness of the planet’s atmosphere may protect them. If the first hypothesis be taken day and night will succeed as they do with us, but the smaller inclination of the axis of Venus to the ecliptic will greatly diminish the seasonal variation. In the day sky, if clouds permit, the sun must be a magnificent object, with a disc twice as large in area as it appears to us. Night conditions may, however, be much more interesting. Venus has no moon of its own, and by far the most conspicuous object in its night sky must be, the Earth when favourably placed. To an observer with sight no better than some exceptional mortals possess, the Earth in opposition should appear as a disc, and not as a mere bright point. Moreover, the motion of our moon round the Earth would be conspicuous, as its greatest distance would be about equal to the diameter of the sun or moon as seen from the Earth. The moon would, of course, be brightest when the Earth appeared “full,” but it is difficult to calculate how bright a star would be to equal the light of the moon. Inhabitants of the moon might very likely have advanced in their astronomical knowledge much further than was possible on the Earth before the invention of the telescope. THE FINEST MOON It has often been remarked how lucky we are in possessing relatively the finest •moon in the Solar system. Jupiter certainly has four moons as large as or larger than ours, but they do not appear larger as seen from Jupiter, and are quite small compared with the planet. The Earth’s moon is not large, but its radius is nearly a quarter of the Earth's radius, so that it is reasonably comparable in size. Mercury is the only planet known to us that would appear brighter from Venus, and its eccentric orbit would be an additional advantage to the primitive astronomers of Venus, if such there have ever been. Mercury also has no moon, and though Mars has two, they are exceedingly small, and give practically no light. Saturn’s unique ring is the only other exceptional appendage in the system. Naturally all the outer planets would be fainter as seen from Venus. It must not be forgotten that it is probable that atmospheric conditions on Venus are extremely bad for observing, as it is considered likely that its sky is permanently overcast.