THE PLANET EARTH

For all the wonders we have learned to perform with the chemical elements, none of them is very impressive when compared with that remarkable arrangement of elements which we know as the planet earth. 

The abundance of some elements and the scarcity of others, the very particular ways in which elements are mixed and compounded, the fact that the elements in our atmosphere cannot escape into space—such natural accidents have made our planet one of those rare fragments of the universe capable of supporting life. 

Everything in this photograph—the clouds over Mexico, the Pacific Ocean along the horizon, and the rock of southern Texas below—is an improbable peculiarity in the universe. 

Oxygen, for example, accounts for but a fraction of one per cent of the substance of the universe, yet it comprises 89 per cent of the weight of clouds and water and 46 per cent of the solid crust of the earth. 

The earth, of course, is entirely composed of the chemical elements, those fundamental building blocks of everything that exists. The millions of different chemical substances on earth are all made up of elements. 

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The last three decades have seen the development of a new science to help us better understand the risk of events about which there is often very little information. The reason there is interest in such a science is that there are a great many societal benefits from activities that involve risk risk that if properly managed through better understanding can greatly benefit the quality of all life on the planet earth, both plant and animal. That science is quantitative risk assessment, also known by such names as probabilistic risk assessment and probabilistic salety assessment, the latter being the preferred name for this text. Probabilistic safety assessment divides the risk question into three questions "What can go wrong " "How likely is it " and "What are the consequences "... 

The chemical elements are substances that cannot be decomposed into simpler substances by chemical means, but combine with other elements to form new substances. All substances and materials other than the elements are made up from the combination of two or more elements. Thus, either singly or in combination with others, the elements constitute all matter. Well over 100 elements occur in nature, but only 92, listed below, occur in the planet earth. 

The process of nitrogen fixation is an essential part of the nitrogen cycle on the planet earth(l). It is estimated that greater than 60Z of the N2 that is ultimately converted to NH4+ is done so by the nitrogenase enzyme system. The availability of fixed nitrogen is often the limiting factor in plant growth( ). To... 

On the planet Earth, the most important photoreaction occurs in green plants or in green or purple organisms. Their photochemical reaction centers contain a special pair of chlorins (cf. the purple bacterium Rhodobacter sphaeroides. Fig. 6.2). Solar photons cause electron transfer and generate a radical ion pair. Within two picoseconds, the negative charge is transferred to a second chlorin, and from it to a quinone. ... 

In general living beings on the planet earth are behaving very differently with respect to their compatibility towards pressurized environment. Some species of microbes are able to suffer several thousand bar and there are sea mammals such as whales which dive down to a depth of 1000 m - equal to a pressure difference of 100 bar - within short time intervals, a procedure which would kill human beings immediately. 

The specific heat at constant pressure (i.e., C ) is a measure of the amount of heat we put into the air, trapped inside the cylinder as shown in Fig. 27.1. Some of this heat is used to increase the temperature of the trapped air by 1°F. The rest of the heat goes into the work required to force the piston up and hence compressing the air surrounding the planet earth. 

Fossil fuels, which fed this amazing economic growth, were the medicine to cure deprivation. But it was an untested medicine, at that. As the planet Earth consumed more and more fossil fuels, two important predicaments started to emerge (1) the fossil fuels would be depleted in a foreseeable future, and (2) the fossil fuels and their combustion products were causing global environmental problems. 

The flame coming from the orange represents a solar flare that shoots from the Sun. Remember, I told you about them when we talked about twisted magnetic fields near the Sun. A huge flare on the sun releases more energy than the planet Earth uses in 100,000 years.16 Just like your match, most solar flares only live for a short time, some only a few minutes. But very large flares can last over an hour. ... 

Our only example of life has been quite successful in dominating the planet. Earth itself presents a variety of environments, some extreme by human standards. One lesson learned from studies of terran biochemistry and its environmental range on Earth is that the life we know requires liquid water. Wherever a source of energy is found on Earth with liquid water, life of the standard variety is present. 

It has been thought for many years that three-fourths of the planet Earth was covered in water, but in... 

Bacteria inhabit every environment on the planet earth. They can be found in temperate as well as tropical areas, in deserts, ice caps, alkali lakes, oceans and hot springs. In one gram of soil, approximately 108 bacteria are present11 and these are estimated to represent over 10000 species. It is estimated that 50% of the biomass on this planet is microbial. Microorganisms represent by far the richest repertoire of functionally and chemically diverse producers of secondary metabolites in nature. 

As we approach the dawn of a new century, we feel deeply anxious for the welfare of the planet Earth, and of the generations that must succeed us. Human numbers are growing explosively. Each human being must eat, keep warm and seek shelter. As we do so, in an evergrowing multitude, we place greater stress on the resources that support us. Already the signs of that stress are universal. The last terrestrial frontiers have been removed, the last solitudes penetrated. 

A Parsec is 206,265 times the distance from the planet earth to the sun, or 3.26 light-years, or 19.2 trillion miles. It is used in astronomy as a standard unit for measurements of stellar distances. 

Figure 4-4 illustrates the concept of the spectrum of human potential. By the simple fact of being bom human, having a certain type of body and nervous system, existing in the environmental conditions of the planet earth, a large (but certainly not infinite) number of potentials are possible for you. 

Radioactivity is a part of nature—in the process of element formation by nuclear reactions taking place in stars, both stable and radioactive isotopes of elements are formed. The isotopic composition of elements is characterized by properties of nuclear reactions that led to the formation of the elements. Elemental composition of the planet Earth, thought to be about 4.5x 10 years old, although not yet in chemical equilibrium, reflects the composition of the material from which it was formed. Therefore, a number of radionuclides occur in nature, having long half-lives (longer than the age of Earth). In addition there are natural processes which continuously produce new radioisotopes. Recently, human activities have also contributed to the increased concentration of some of the radionuclides. 

Mold is part of the taxonomic fungi kingdom. These kingdoms (Monera, Protista, Fungi, Plantae, Animals) represent the known life-forms on the planet Earth. 

Combine disparate aspects of present understanding and predict future observations and trends in this primary area of man s search for truth. And if it is a good theory, it may also provide an understanding which could assist in improving the condition of man, the relationships between his societies and nations, and the increasingly fragile bond linking him with his only available home, the planet Earth. 

At this time, only space disposal can provide absolute protection for humanity, its descendants and the planet earth. New methods may be discovered in the future, but current planning should include the accounting for disposal of decommissioned reactor materials in space. Whatever method is selected, good initial planning will make the disposal of the old fusion reactors a safe, relatively easy, and cost effective process. 

They flopped down, utterly exhausted from their trip, resting for eons. They explained to me in a kind of thought language that they were fleeing from something out in space. They had come to the planet earth to escape their enemy. 

It can be seen from Table 3 that the dissipation of noble gases was particularly intense. This is reasonable, since these gases did not react with the solid or liquid materials forming the planet Earth. On the other hand the loss in the case of hydrogen was relatively small, a significant portion of this element remained in a condensing compound (water). 

The planet earth receives 4.3 x 1020 J/h of energy from the sun while the requirement of energy for the earth is around 4.7 x 1016 J/h and it shows that if one can harness completely the solar energy for one hour, it will be sufficient to satisfy the energy need of the world for more than a year [17]. 

Table 11-8 summarizes the results. Again it should be emphasized that the fluxes derived are current ones and that the uncertainties are considerable, even though Garrels and MacKenzie (1972), Garrels and Perry (1974), and Holland (1978), all using similar procedures, have obtained comparable results. To indicate the range of values, the estimates of the first authors are included in Table 11-8. The fluxes may also be used to calculate the residence times of carbon in the participating reservoirs, and Table 11-8 includes these data. The longest residence times are associated with the sediments on account of the high carbon content of this reservoir. The values of a few hundred million years indicate that carbonates have turned over at least 10 times since the first deposits occurred after the planet earth had formed 4.5 billion yr ago.

Rubisco is the probably the most abundant protein on the planet Earth. It contains two important activities. 

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