THE AIR ON VENUS

Greymouth Evening Star, 17 November 1934, Page 3

THE AIR ON VENUS

DEADLY TO MAN Two years ago Dr. W. S. Adams and Dr. Theodore Dunham, of Mount Wilson Observatory, discovered carbon dioxide in. the atmosphere of the planet Venus. It is a heavy gas, this carbon dioxide. Beer, soda water, ginger ale, champagne are charged with it. All the vegetation on earth got its carbon from it—an important argument in the arsenal of those who like to think that Venus is a living world. Still there is very little carbon dioxide in our atmosphere —about 0.05 per cent, by weight. On the other hand, Venus has as much carbon dioxide by weight as the total weight of the earth’s atmosphere (approximately ten followed by fifteen zeros of tons). No human being could live in air like that. But there might be vegetation of the lush typo that we associate with dense primeval jungles on the earth when coal Was being formed. These facts about the carbon dioxide atmosphere aroused the interest of Dr. Arthur Adel, of the University of Michigan’s physics department. After all, Venus is a good many millions of miles away. While there is no reason to doubt the inferences made about the atmosphere of Venus —the whole of astrophysics is mere inference by the same token—why not reproduce the conditions here and thus verify the inference?

If you were to enter Adel’s laboratory you would never recognise Venus. There are big flasks containing carbon dioxide, a long tube, a spectroscope, a plate holder. This is all that Dr. Adel needs to reproduce in his laboratory the little that he needs of Venus.

CONDUCTING THE EXPERIMENT Under natural conditions light travels from the sun io Venus. The atmosphere of Venus then reflects the light to the earth. Ordinarily the spectroscope would spread the light out into a pretty rainbow. It does so oven when the light of Venus is thus reflected. Look sharply however—better still, make a photograph —and you see that certain tints (wave lengths) are missing. They have been absorbed by the atmosphere of Venus. Adams and Dunham easily identified those absorbed wave lengths because they tire those that are characteristic of carbon dioxide. Into the previously mentioned tube —it is twenty-five yards long —carbon dioxide under a. pressure of fifty atmospheres (about 73b pounds) hisses from steel bottles, like those supplied fo soda-water fountains. A beam of light is then shot down the tube and reflected back, so that it must pierce fifty yards of this artificial Venusian atmosphere. Whereupon it passes through a spectroscope and is photographed. Adel looks at his pictures. There he sees the tell-tale gaps that proclaim tho existence of carbon dioxide. The case for a carbon dioxide atmosphere on Venus is thereby strengthened.