NEBULA SCIENCE FICTION

Solar System Ecology

John Newman

Issue 30 - May 1958


An example of the many scientific articles which were featured in NEBULA and one of the first mentions in a science fiction magazine of terraforming and the science of ecology.


Is there life on other worlds? This is a question which has fascinated mankind every sine the study of astronomy as we know it first began. In this article a popular scientific writer gives his answer in the light of the latest available information.

Out there, beyond the limits of Earth's atmosphere, lies a Universe new to mankind. Already the coming "conquest of space" is referred to quite casually. Man is on his way up and out.

Out there lies a Universe where water and oxygen are rarities, where cold and heat and sleeting radiation surpassing anything experienced by Man are the signposts to the new frontier of space.

 The sign says "Earthman, stay home." 

But, of course, he won't. Soon there will be intelligent life on other planets-human life. Scientists are intrigued enough to speculate now about what sort of life, if any, will be waiting to shake hands or tendrils tendrils.

Ecology is the science oft the inter-relationship of living organisms and their environments. By applying their knowledge of terrestrial conditions, by ingenious use of costly and complicated equipment, by correlating facts from different branches of science, and by sheer speculation, ecologists and physiologists have recently been attempting to find an answer to the long-plaguing query: "Is there life on other planets?"

The short answer is: "Yes." The logical one is: "Wait and see." Not one of the planets of the Solar System will be a paradise for colonists-each will offer a continual struggle for survival. None of the planets can sully us with anything that we don't have right here on Earth, as as we know now. Man will either have to create small zones a which he can fit his own ecology; or he will have to adapt bodily. 

Curiously enough, we know less about the conditions on the surfaces of most of the planets of the System than we do about the surfaces of many of the stars. Mercury always has one face turned towards the Sun; almost half of the planet is always in darkness. Venus, our nearest and brightest neighbour, has an impenetrable cloud layer that reflects most of its sunlight. Jupiter, Saturn, Uranus and Neptune have so highly compressed and deep atmospheres that their true surfaces are invisible. Pluto is too distant to show even as a disc; in the 200-inch telescope Pluto appears as a star-like point of light. 

So, while our present knowledge of the Solar System gives no direct evidence of any past or present intelligent life, it is impossible to be dogmatic. No science can give an absolute answer when insufficient facts are available.

 Life is the most curious phenomenon of which we know. The only general definition of life is one involving entropy, the tendency for all forms of energy in the universe to degenerate into heat and so increase the entropy of the universe. If part of this energy flow is diverted and used for the purposes of an organism, then this is life. The conditions for life cover practically the whole globe of Earth-the only places where life of some sort cannot exist are those where there is no liquid water.

 But terrestrial life is based on the chemistry of a few light elements and one particular physico-chemical process, the ulitisation of photosynthesis to obtain the energy necessary for life-either directly by plants using chlorophyll, or by other types eating part of a chain of life that has its beginnings  in  photosynthesis. Carbon is always present; atoms of it joining to form millions of different compounds. The other main ingredients of living matter are hydrogen, nitrogen and oxygen, together with a little of the medium weight elements such as iron and iodine. Most of the heavier elements' compounds are poisonous and are not biologically useful, although it is interesting to note that grass will not grow in the absence of traces of cobalt.

Water is an important single factor, for it is found in all terrestrial life, acting as a solvent and allowing many of the biological constituents to travel through the body. It also acts as a heat exchange fluid removing heat from the muscles, and it is a raw  material. together with carbon dioxide, in the formation of sugars and starch. 

Having  grasped this rough outline of what life as we know it demands, can we extrapolate the laws governing life on Earth to to conditions elsewhere? Other forms of life may be possible; life based on different chemistries from that of carbon; life obtaining its energy directly from atomic fission or fusion or from magnetic or electrical field forces; life so alien that we may not t recognise  it as such. 

And there are other chemicals that might be useful in the building block stages of life. We know that liquid ammonia has many of the solvent properties of water and is present on Jupiter, Saturn, Uranus and Neptune. Liquid sulphur may have similar properties with sulphides and silicon imitates carbon in forming a large series of compounds. With a variety of possibilities before the always urgent power of life, it is well to remember that the Solar System contains eight other planets, one star, several thousand asteroids and thirty satellites, and one of which may contain some form of life.

But the temperatures in this  system range from the 5,000 degrees C at the Sun's surface, to absolute zero, -273 degrees C on Pluto. Apart from some bacteria and seeds which can withstand a temperature of  120 degrees C for several hours, and together with some algae, lichens and mosses, can exist in a dormant state at liquid helium temperatures, near - 233 degrees C, active life can exist only in the range from -5 degrees C, just below freezing water, to 80 degrees C. It is in this 80 degrees C range that we must look for habitable planets; with the proviso that sunlight, carbon dioxide for plants, oxygen and water are all also available.

 The Solar System, in more ways than one, revolves around the Sun. There is only a small shell, about 75 million miles wide, around the Sun in which there can exist a planetary environment at a temperature suited to life as we know it. In this band we find Venus, Earth and Mars. It does not matter if the temperature range is greater than that of 85 degrees C; life can probably go through a dormant phase outside it. 

Mercury is too near the Sun; sunward face with a temperature above boiling lead, near 400 degrees C; dark face below the temperature of liquid nitrogen -253 degrees C. The outer planets beyond Mars are all too cold for active life; Jupiter's temperature is near -100 degrees C and the planetary temperatures decrease through the series out to Pluto. 

So we are left with two planets; Venus shrouded in mystery, and Mars. Nothing is known of Venus' surface; the upper atmosphere contains no water or oxygen, but a great deal of carbon dioxide. It receives almost twice as much solar radiation per unit area as does Earth; temperature near the equator is about 55 degrees C at mid­day. Water and oxygen may exist near the surface; although it might be expected to rise above the heavier carbon dioxide, so that the Venus dust-bowl theory may, as well as the jungle theory, be near the truth. 

Mars has an atmosphere of sorts and near the tropics varies from 30 degrees C at noon to -70 degrees C at night. Whilst the Martian climate is subjected to larger temperature differences than Earth during one day, the temperatures do include an active living range. There are no seas or mountains; yellow dust storms are frequent, but the atmosphere does contain carbon dioxide and water. Clouds can occasionally be seen and it has recently been proved that the polar caps are composed of ice. Unfortunately, no oxygen can be detected. The Martian atmosphere is similar to that 10 miles above Earth and water would boil at 43 degrees C instead of the 100 degrees C at Earthly sea level. 

This eliminates the possibility of Earthly type warm blooded animals; but the green areas of Mars change colour, yellow to brown following seasonal changes. They must be self-perpetuating, or the blanket of dust would cover them. The infra red spectra of the Martian surface is similar to that reflected from plant life upon Earth. 

Biologically speaking, Mars is not a dying planet; it is a young world, as is shown by the amount of carbon dioxide present. 

The satellites of the Solar System are all small and not one is large enough to hold even as much atmosphere as Mars, whilst most have as little as our satellite, the Moon.

So, by our standards, the greater part of the Solar System is unhealthy for terrestrial life. But encysted bacteria  in a dormant and spores in a dormant state could travel across space, driven by light pressure, so that we might expect to find some form of recognisable life wherever conditions are moderate enough. 

Apart from other considerations, it would seem that again only Mars and Venus might be made suitable for human life.

Mars could be reconstructed using unlimited thermo-nuclear power to decompose the surface rocks to increase the atmosphere so that more complex plants could grow, through the irrigated water supplies and the heat in the atmosphere. 

Venus would be more difficult to "terraform." The whole atmosphere would have to be converted, water and oxygen created to make a habitable planet. This type of giant programme of planet reconstruction certainly will not be worth while until the utmost use has been made of the Earth's surface; deserts irrigated, jungles cleared,  mountains removed [sic-JL] and the natural wealth of the Earth properly and sanely used. Any  project on Earth would be simpler  than tackling another planet. 

The  other alternative, one that belongs to science fiction, is to adapt Man to his environment. If a planet such as Mars his less oxygen than Earth, then the colonists must be bred for extra lung capacity and the ability to withstand cold. Even so, it is difficult to conceive of any adaptation of the human body being able to live on the planets beyond Mars. 

Still, we know little of the other planets and less about the conditions on their surfaces. We cannot really be certain about anything until we visit them. As we will.

Unless we are visited first.


 HOME