Venus is a scorched world

Title

Creator

Japan Fortnightly, 1968

Language

English

Year

1968

Rights

In Copyright - Educational Use Permitted

Abstract

Experiment to create Venusian Atmosphere on Earth.

Fulltext

■ Experiment to Create Venusian Atmosphere on Earth. VENUS IS A SCORCHED WORLD The surface of Venus is charred black. There, wood, paper or cloth do not burn. Yet, they produce smoke and are instantly scorched black. Such is the strange world of Venus where everything burns up without flame or fire. This has been confirmed by experiments which simu late the atmospheric condi tions on the surface of Venus carried out by the Asahi Shimbun Publishing Co., one of Japan’s major newspaper publishers, in cooperation with the National Institute of Metals of the Government’s Science and Technology Agency. When the results of the sur vey by the Soviet Union’s un manned probe, Venus 4, were announced, many scientists thought that “on the surface of Venus, everything burns furiously.” But this specula tion has now been repudiated. There is not enough oxygen on Venus, so nothing burns there. However, it is a veri table inferno of intense heat. If a human being without a protective device against heat should land on Venus, he would instantly become a charred corpse. 22 Atmospheres, 270° C, and 0.4-0.8% Oxygen The atmospheric conditions on the surface of Venus were minutely observed by the Soviet probe on October 1^, 1967. The unmanned sur veyor was soft-landed with a parachute and conducted a survey of the Venusian atmo sphere as it descended. Ac cording to the data thus col lected, the surface of the pla net has a temperature of 270°C. an atmospheric pres sure of 15 to 22, and the at mosphere itself consist pri marily of carbon dioxide with an oxygen content of only 0.4 to 0.8 per cent and water vapor of 0.1 to, 0.7 per cent. Compared with the earth’s atmosphere which contains 21 per cent oxygen, the Ve 34 Panorama nusian atmosphere contains an extremely small amount. In the light of the fact that Venus has twenty-two atmo sphere and a temperature of 270° C, the absolute quantity of oxygen in the atmosphere is not at all small. One liter of Venusian atmosphere con tains one-seventh — one-third nf the oxygen content cont lined in one liter of the earth’s atmosphere; Because both the atmo spheric pressure and the tem perature are high, the oxygen in the Venusian atmosphere is expected to be far more active than that in the earth’s atmosphere. This is,the rea son why it is surmised that combustion there would be far more vigorous than on the earth. But, is this actually the case? At a temperature of 270° C, tin melts but lead does not. Under 22 atmo spheres, water boils at 216° C. This much is definitely known. But beyond this, the scientists can only guess. To simulate conditions of another planet on this earth is one area of experimental astronomy and it was thought that such an experiment would be of great help in pro ducing a realistic picture of the other planet. Simulation of the Atmosphere For the simulation experi ment, an autoclave of the Na tional Institute of Metals was used. An airtight cham ber used in chemical and me tallurgical experiments, it is filled with gasses or liquids at high temperatures or pres sures in order to test their re actions. The autoclave used in this particular test had an inter nal volume of 500 cubic cen timeters. It had two windows at the bottom, one admitting light and the other for mak ing observations. The artificial Venusian at mosphere was created by mix ing carbon dioxide, oxygen and water proof. Since the Venus 4 probe failed to detect any nitrogen gas in the Ve nusian atmosphere, this ele ment was ignored. The following mixture of gases was used in the experi ment: May 1968 35 Carbon dioxide Oxygen Water Nitrogen Atmospheric pressure Temperature Venusian Atmosphere 90-95% 0.4-0.8% 01-0.7% not detected 15-22 270°C Simulated Atmosphere 98.5-99.5% 0.4-0.8% 01-0.7% 0% 15-22 270°C This mixture of gases was placed in a 30-liter tank and then transmitted to the auto clave through a preheating tank at the rate of 500 to 1,000 cubic centimeters per minute while the pressure in the chamber was kept at 22. The gas mixture was removed from a second exit. With this arrangement, the autoclave was constantly refilled with a fresh mixture of gases. No Combustion Because of Lack of Oxygen A variety of specimens were placed in this chamber to observe any changes that they might have undergone while the temperature in the chamber was increased up to 270° C. The test materials were chosen from among common items readily avail able in order to facilitate our understanding. Under the pressure of 22 atmospheres and at room temperature, it was learned that small electric bulbs used in flashlights, pingpong balls and quial eggs were able to withstand this pressure. Un der the same pressure, how ever, killifish in water in a beaker died instantly in the autoclave. When the tempe rature was raised, the water boiled and evaporated and the killifish was scorched. A match, the head covered with combustible chemicals, ignited spontaneously at around 150° C, but the fire thus started did not burn the wooden stick which, instead, began to scorch at about 170°C and became charred around 200° C. This carbonized match stick would burn in ordinary air with a red glow at about Panorama 350°C. In the artificial Ve nusian atmosphere, however, it did not burn even when the temperature was raised to 400°C. After the temperature was raised above 300°C, how ever, the carbonized match either bent or splintered and gradually became thinner. With wh*t percentage of oxygen in the Venusian at mosphere, then, would the carbonized match stick began to burn? In an experiment in which the oxygen content in the car bon dioxide was raised gra dually from 3 per cent to 5, 10, 20 and 30 per cent, the match stick did not burn at 10 per cent. With an oxygen content greater than 20 per cent, however, it began to burn at 230°C. That is to say, even when the atmospheric pressure is as high as 22 and the tem perature as much as 270° C, a match stick does not burn if the oxygen content is only from 0.4 to 0.8 per cent. The same may be said of sulphur which readily burns in the air. Sulphur burns spontaneous ly in the earth’s atmosphere at 230°C. In the man-made Venusian atmosphere, how ever, it merely melts and turns into an amber-colored fluid. It furiously emits smoke but does not create the whi tish blue flame which is char acteristic of the combustion of sulphur in the air. Even when the oxygen content was increased to IQ per cent in the autoclave, sulphur did not burn, but it did when the oxygen content was increased to 20 per cent. In the Venusian atmosphere of 270° C, even absorbent cot ton, gauze and handkerchiefs simply became carbonized. But these carbonized mate rials proved surorisingly stur dy. They could be, with some care, folded or unfold ed, without crumbling to pieces or turning into ashes. Does all this mean that no thing ever burns in Venus’ atmosphere? The head of a match burn ed, to be sure. But this was because the tip was covered with chemicals containing po tassium chlorate, an oxidizer. It would burn even in an at mosphere containing carbon dioxide alone or even in va cuum because of the effect May 1968 37 of the oxidizer it contains. This would be true with cel luloid which consists primari ly of nitrocellulose, such as a pingppng ball. There are some things, however, which do burn in the Venusian atmosphere be cause of the slight amount of oxygen contained in it. The fine particles of mag nesium is one example. Mag nesium powder which used to be used for flash-light in pho tography, does not burn spon taneously even when heated up to 360° C in the air. But if mixed with an oxidizing agent, such as used in a match, it can be made to burn instantly with a flash when the agent is ignited at tem peratures • around 150°C. When the same substances are placed in a container with carbon diox’de with 22 atmo spheres and heated, the oxi dizing agent of the match alone burns at temperatures around 150°C while the mag nesium powder does not. When the same experiment is conducted in the simulated Venusian atmosphere, how ever, magnesium, too, is ig nited and burns instantly. In the Venusian atmosphere which contains a very small amount of oxygen, only a small of substances including magnesium burn. Even ben zene does not burn there. When a cigarette is lighted in the earth’s atmosphere and placed in a test tube, which in turn is placed in the Venu sian atmosphere, the cigarette is instantly extinguished, pro ducing a large nuantitv nf smoke and tar while the ci garette itself becomes char red. Water under 15 atmo spheres boils at 197°C and under 22 atmospheres at 216°C. In the Venusian at mosphere, heavv oil evapo rates instantly leaving only a dark brown residue. As said before, the oxygen content in one liter of the at mosphere on the surface of Venus is from one-seventh to one-third that in the same amount of the earth’s atmo sphere. Yet, despite this re lative abundance of oxvgen in the earth’s atmosphere, things do not burn as readily as they might be expected. This, reasons Dr. Tsuyoshi Hikita of Tokyo University, is because “in the earth’s at mosphere, carbon dioxide, too, is equally compressed 38 Panorama and this, among other things, impedes combustion because it deprives the heat necessary for burning.” “If we took a substance whose temnerature is several thousand degrees,” says Pro fessor Hikita, however, “to the surface of Venus, the hiqh temperature itself would dis sociate oxygen from carbon dioxide, and then that oxvqen would cause the sub stance to burn.” Apart from the combustion experiments, a test was also conducted for checking changes that occur in metals in the Venusian atmosphere. This was done with stainless steel, magnesium, pure iron and aluminum, whose speci men pieces were left alone for one week in the simulated atmosphere. The result show ed that the iron became co vered with a black coat of rust which in turn prevented the iron from further rusting. Stainless steel, magnesium, and aluminum, also, rusted. Specialists have said that “metal pieces rust rapidly in the Venusian atmosphere, which has less oxygen than the earth’s because of the high temperature.” Another factor in causing the metals to rust may be that oxidiza tion takes place because of the oxygen created by the dissociation of carbon dio xide, besides the 0.4 to 0.8 per cent oxygen in the at mosphere. Further Approach to Real Atmosphere The data obtained through the above experiments seem to repudiate almost all the hypotheses hitherto advanced by many scientists concern ing Venus. The theory advanced by Svante Arrhenius (18591927), the Nobel Prize-win ning Swedish scientist, and Dr. Graviil A. Thikhoff, the late Soviet space biologist that “Venus is covered with vegetation” is now totally in conceivable. The theory of Dr. Fred L. Whipple (1906), director of the Smith sonian Astrophysical Obser vatory, and Dr. Fred Hoyle (1915-), a British'astronomer, who both advanced the theo ry that there would be “sea of petroleum” on the surface of Venus, too, would be im possible. For water and pe troleum would evaporate and Mat 1968 39 any plant would instantly turn into charcoal. The only remaining hypo theses yet to be repudiated is that the surface of Venus is an intensely hot, barren desert. Yet, there is no way of knowing as yet whether the entire surface is desert or if there are high mountain ranges as on the earth and if plant life and microbes might be found at places on the high mountains where the temperature is low. On these questions, there is now only speculation. The experiments jointly conducted by the Asahi Shim bun Publishing Company and the National Institue of Me tals have made a major con tribution in changing much of the speculation about Ve nus into reality. In order to learn more of the realistic facts of life on Venus, how ever, it will be necessary to send more sophisticated sur veying instruments to its sur face. It is no mere dream to ex pect that someday such na tions as the United States and the Soviet Union, coun tries which are capable of launching rockets, will launch Venus probes one after an other and establish a coope rative relationship in space science, and conduct experi ments by reproducing on the earth conditions similar to those on Venus with the fur ther data obtained from such Venusian probes. These re cent experiments in Japan will undoubtedly contribute to stimulating further efforts to reveal the secrets of Ve nus and other planets of our solar system in the interests of greater international coo peration and understanding. — Japan Fortnightly, 1968 40 Panorama

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