Aliens Atomic Rockets. So we must strike beyond physiology and reach into chemistry, saying that all life is made up of a directing set of nucleic acid molecules which controls chemical reactions through the agency of proteins working in a watery medium. There is more, almost infinitely more, to the details of life, but I am trying to strip it to a basic minimum. For life as we know it, water is the indispensable background against which the drama is played out, and nucleic acids and proteins are the featured players. Hence any scientist, in evaluating the life possibilities on any particular world, instantly dismisses said world if it lacks water or if it possesses water outside the liquid range, in the form of ice only or of steam only. You might wonder, by the way, why I dont include oxygen as a basic essential. I dont because it isnt. To be sure, it is the substance most characteristically involved in the mechanics by which most life forms evolve energy, but it is not invariably involved. There are tissues in our body that can live temporarily in the absence of molecular oxygen, and there are microorganisms that can live indefinitely in the absence of oxygen. Life on earth almost certainly developed in an oxygen free atmosphere, and even today there are microorganisms that can live only in the absence of oxygen. No known life form on earth, however, can live in the complete absence of water, or fails to contain both protein and nucleic acid. In order to discuss life not as we know it, lets change either the background or the feature players. Background first Water is an amazing substance with a whole set of unusual properties which are ideal for life as we know it. So well fitted for life is it, in fact, that some people have seen in the nature of water a sure sign of Divine providence. This, however, is a false argument, since life has evolved to fit the watery medium in which it developed. Life fits water, rather than the reverse. Can we imagine life evolving to fit some other liquid, then, one perhaps not too different from water The obvious candidate is ammonia. Medical Physiology Boron Torrent Pdf Books' title='Medical Physiology Boron Torrent Pdf Books' />Ammonia is very like water in almost all ways. Whereas the water molecule is made up of an oxygen atom and two hydrogen atoms H2. O for an atomic weight of 1. NH3 for an atomic weight of 1. Liquid ammonia has almost as high a heat of evaporation, almost as high a versatility as a solvent, almost as high a tendency to liberate a hydrogen ion. In fact, chemists have studied reactions proceeding in liquid ammonia and have found them to be quite. Ammonia chemistry has been worked out in considerable detail. Issuu is a digital publishing platform that makes it simple to publish magazines, catalogs, newspapers, books, and more online. Easily share your publications and get. DAMADEI Design and Advanced Materials As a Driver of European Innovation, How is a designer to keep abreast the latest developments in material science and develop a. Cheri Magazine there. Ammonia as a background to life is therefore quite conceivable but not on earth. The temperatures on earth are such that ammonia exists as a gas. Its boiling point at atmospheric pressure is 3. C. 2. 8 F. and its freezing point is 7. C. 1. 08 F. But other planets In 1. Jupiter, and, to a lesser extent, of Saturn, was loaded with ammonia. The notion arose at once of Jupiter being covered by huge ammonia oceans. To be sure, Jupiter may have a temperature not higher than 1. C. 1. 48 F., so that you might suppose the mass of ammonia upon it to exist as a solid, with atmospheric vapor in equilibrium. Too bad. If Jupiter were closer to the sun. But wait The boiling point I have given for ammonia is at atmospheric pressure earths atmosphere. At higher pressures, the boiling point would rise, and if Jupiters atmosphere is dense enough and deep enough, ammonia oceans might be possible after all. An objection that might, however, be raised against the whole concept of an ammonia background for life, rests on the fact that living organisms are made up of unstable compounds that react quickly, subtly and variously. The proteins that are so characteristic of life as we know it must consequently be on the edge of instability. A slight rise in temperature and they break down. A drop in temperature, on the other hand, might make protein molecules too stable. At temperatures near the freezing point of water, many forms of non warm blooded life become sluggish indeed. In an ammonia environment with temperatures that are a hundred or so Centigrade degrees lower than the freezing point of water, would not chemical reactions become too slow to support life The answer is twofold. In the first place, why is slow to be considered too slow Why might there not be forms of life that live at slow motion compared to ourselves Plants do. A second and less trivial answer is that the protein structure of developing life adapted itself to the temperature by which it was surrounded. Had it adapted itself over the space of a billion years to liquid ammonia temperatures, protein structures might have been evolved that would be far too unstable to exist for more than a few minutes at liquid water temperatures, but are just stable enough to exist conveniently at liquid ammonia temperatures. These new forms would be just stable enough and unstable enough at low temperatures to support fast moving forms of life. Nor need we be concerned over the fact that we cant imagine what those structures might be. Suppose we were creatures who lived constantly at a temperature of a dull red heat naturally with a chemistry fundamentally different from that we now have. Could we under those circumstances know anything about earth type proteins Could we refrigerate vessels to a mere 2. C., form proteins and study them Would we ever dream of doing so, unless we first discovered life forms utilizing them Anything else besides ammonia now Well, the truly common elements of the universe are hydrogen, helium, carbon, nitrogen, oxygen and neon. We eliminate helium and neon because they are completely inert and take part in no reactions. In the presence of a vast preponderance of hydrogen throughout the universe, carbon, nitrogen and oxygen would exist as hydrogenated compounds. In the case of oxygen, that would be water H2. O, and in the case of nitrogen, that would be ammonia NH3. Both of these have been considered. That leaves carbon, which, when hydrogenated, forms methane CH4. ALIENS. Intelligent races who are not EARTH HUMANS. The term as such is never used for nonintelligent species, however unearthly, though in TECHJARGON these may be. I celebrate myself, and sing myself, And what I assume you shall assume, For every atom belonging to me as good belongs to you. I loafe and invite my soul. Several of her books online, including Little Lord Fauntleroy, A Lady of Quality, and The Secret Garden. At Project Gutenberg. Medical Physiology Boron Torrent Pdf Books' title='Medical Physiology Boron Torrent Pdf Books' />There is methane in the atmosphere of Jupiter and Saturn, along with ammonia and, in the still more distant planets of Uranus and Neptune, methane is predominant, as ammonia is frozen out. This is because methane is liquid over a temperature range still lower than that of ammonia. It boils at 1. 61. C. 2. 59 F. and freezes at 1. C. 2. 97 F. at atmospheric pressure. Could we then consider methane as a possible background to life with the feature players being still more unstable forms of protein Unfortunately, its not that simple. Medical Physiology Boron Torrent Pdf Books' title='Medical Physiology Boron Torrent Pdf Books' />Ammonia and water are both polar compounds that is, the electric charges in their molecules are unsymmetrically distributed. The electric charges in the methane molecule are symmetrically distributed, on the other hand, so it is a non polar compound. Now, it so happens that a polar liquid will tend to dissolve polar substances but not nonpolar substances, while a nonpolar liquid will tend to dissolve nonpolar substances but not polar ones. Thus water, which is polar, will dissolve salt and sugar, which are also polar, but will not dissolve fats or oils lumped together as lipids by chemists, which are nonpolar. Hence the proverbial expression, Oil and water do not mix.