The Sun-Earth-space system 

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... system. This must be well defined with regard to space and time. The motive force of the flow of energy and/or matter through the system is the contrast or the level of order. From above we know that a part of this must always be destroyed in order to create action and time. The quality of the energy and/or matter constantly deteriorates in the flow passing through the system. The concept of entropy, or rather negentropy (i.e. entropy times –1), is a measure of the level of order. Energy and/or matter are falling from high order, i.e. low entropy or high negentropy, in the inflow into low order, i.e. high entropy or low negentropy, in the outflow. This is a necessary condition if the flow is to have a definite direction in space and for time to exist, as indicated above. This is also expressed as a destruction of exergy. Energy and matter only serve as carriers of contrast, which is consumed when it flows through a system. When energy and matter flow through a system, a very small part of this may sometimes be stored in or removed from the system. If there is a balance between inlets and outlets of energy and matter, the system will remain unchanged, a kind of dead state that is described in Figure 1. Such dead state systems are the moon and a car. The moon offers us moonlight and a car is a mean of transport, however, the systems remain in principal unchanged. According to this way of looking upon flows of energy and matter it is wrong to say that energy and matter are produced or consumed. It is only contrast that can be produced or consumed. If an old car stands in the open air getting rusty, the material deteriorates in contrast but the matter still exists. It will combine with the environment in new chemical combinations, i.e. new chemical substances of less contrast to the environment. From a socio-economic point of view, we can say that the car and its material decrease in value and, as time passes, become of no value. In this case the energy and matter is removed from the system, and we have a state of decay. If energy and/or matter are stored in the system we may have a viable state, i.e. life may occur. Logic would suggest therefore that the existence of life and the evolution of life imply that energy from the Sun must be stored on Earth. On the surface of the Earth, at many different levels of size and of time-scale, systems operate by involving many kinds of matter in a complex pattern. Energy and matter permanently flow through different systems on the Earth’s surface. Many branches of science, e.g. hydrology, climatology, oceanography, and ecology, study this. It is impossible to fully understand how all these systems and flows of energy and matter cooperate. Figure 2 offers a model for all the systems of the Earth’s surface simplified by a network of 5 spheres; atmosphere, hydrosphere, lithosphere, biosphere and sociosphere. It must be remembered that this separation of the Earth into five spheres is just a model and the distinction between the spheres are not always accurate. Also it is important to remember that the whole is always more than the sum of its parts. The model is not exact but a guide to better understand some global processes. The atmosphere contains about 78 percent of nitrogen, about 21 percent of oxygen, and the rest as argon, carbon dioxide, water vapor, ozone, and other gases. Water, mainly in the hydrosphere, appears simultaneously as ice, water, and steam, i.e. solid, liquid, and gas. Furthermore, water is an enormous heat reservoir, thereby balancing temperature variations both in space and time on the Earth. The lithosphere is the solid bedrock with all its minerals and salts, which by erosion is dissolved and becomes an important nutritive in the water. The biosphere consists of all living organisms on the Earth, except modern man, whose world constitutes the sociosphere, together with all the man-made systems. Plants and animals consequently belong to the biosphere, and buildings and machines belong to the sociosphere. Only so-called primitive people and their belongings are hosted by the biosphere. The exact definitions of these spheres are not essential for the discussion. Sociosphere and technosphere may be regarded similar. All these spheres interact with each other in a mostly constructive manor, e.g. the evolution of life, creation of free oxygen and fossil fuels from the living processes of the biosphere. Further examples are erosion to mineralize water and sedimentation to remove toxic substances from the biosphere. However this interaction may also be destructive, e.g. volcanic eruptions, hurricanes, ozone depletion, greenhouse effect, and an increase in DDT and PCB in the biosphere. Figure 2 illustrates the interaction as lines between the spheres. Exergy is consumed in the constant flows of energy and matter that go on within and between these spheres. The driving force is exergy, which mostly originates from the contrast between the Sun and space, see Figure 3. The source of exergy on the Earth is secured from the contrast between the Sun and space. The Sun is a star, i.e. an extremely compact and hot body that emits light, whereas space is the opposite, i.e. almost empty and cold. This is a system of extreme contrast. The life support systems on the Earth are equally dependent on both of them, but this is not enough. The Earth is the only planet in the solar system of suitable size and distance to the Sun for life, as we know it, to evolve. The size, which implies the gravity of power, is big enough to keep an atmosphere of gases such as oxygen and nitrogen to its surface. But, the size is not too big. On the Sun, the gravity of power is so big that it ignites the fusion of hydrogen into helium, which releases a huge amount of stored energy. This also makes it impossible for life to appear on its surface. The distance between the Earth and the Sun gives a suitable ambient temperature, which is perfect to simultaneously sustain ice, water, and vapor. On planets closer to the Sun, such as Venus, all water would be evaporated and on planets further away from the Sun, Mars for instance, the water would remain frozen. These are all important factors for a life support system. This makes the Earth the only carrier for the evolution of life in our solar system. The Earth is the only planet able to successfully capture the contrast of the “Sun-space” system. The Earth is provided with life support systems, which makes it suitable to host the living Nature, i.e. the process of evolution of life. This makes our planet unique, perhaps in the whole of the universe. The exergy of sunlight is on the average about 93 percent of its energy value. The incoming solar energy is equivalent to about 1.6 × 10 17 W of exergy, see Figure 4. This is about 13 000 times the exergy that is presently being used as energy and material resources by the human society, which is about 1.2 × 10 13 W or on the average about 2 kW per capita. However, this use is very unequally distributed among the people of the world, the average American uses about 10 kW whereas the average Chinese uses about one 1 kW and the people of India even less. Living nature, or the biosphere, is subject to three fundamental processes, namely: production, consumption, and decomposition. These maintain the circulation of matter by using the incoming solar exergy in a sustainable and evolutionary way, see Figure 5. Exergy is the “fuel” for living systems, that are sustained by converting energy and materials; e.g. a living cell, an organism, an ecosystem, the Earth’s surface with its material cycles, or a society. The green plants, which represent the production process, convert exergy from the sunlight into the exergy-rich matter of biomass, via photosynthesis. The exergy as biomass then passes through different food chains in the ecosystems. At every trophic level exergy is consumed and decomposition organisms dominate the last level in this food chain. There is no waste. The main problem for nature does not seem to be lack of natural resources, such as solar energy, but how to make use of this immense amount of available exergy in a creative manner. This is not a matter of spending it, but the opposite, namely to capture it into new forms of contrast, i.e. to build ordered structures. This is a delicate problem far beyond the imagination of human beings. We just happen to be a part of this highly intelligent process of evolution. Exergy is captured by nature through structural and chemical changes on the Earth. This is shown as a net-flow of “unwanted” substances away from the biosphere and stored in fossils and minerals in the lithosphere, see Figure 5. Thus, a minor part of the incoming solar energy is stored on the Earth, which is a key element in nature’s process of ...