Ecology: The Biology of Interactions. 2.10. (Supplement) The Evolution of the Universe, the Solar System, and the Earth
The age of the Earth, and of the Solar System, is 4.6 billion years. The Sun and planets formed from a gas-dust cloud produced by the destruction of preceding stars. Nuclear transformations in former stars are the reason for the diversity of chemical elements on Earth that makes life possible...
Ukrainian language (latest version) / Russian language (no longer updated) 2.09. The Biogeochemical Cycle of Phosphorus
2.09. Biogeochemical cycle of phosphorus
D. Shabanov, M. Kravchenko. Ecology: The Biology of Interactions Chapter 2. Biospherology
2.11. (supplement) What Is Life?
2.10. (supplement) The Evolution of the Universe, the Solar System, and the Earth As long as you feel the stars as something “above you,” you do not yet possess the gaze of the knower. Friedrich Nietzsche In describing the origin and development of the Universe, science simultaneously displays both strength and weakness. We have detailed descriptions of the evolution of the Universe corresponding to different theories. These theories use exceedingly complex mathematical apparatus, and the events they describe completely contradict common sense. Nevertheless, none of these theories is universally convincing; further study of our Universe leads to new and often paradoxical discoveries. The age of the Universe is about 13.8 billion years (Fig. 2.10.1). It arose as a result of the so-called Big Bang, an event that does not fit within the framework of common sense. The consequences of this event included not only the emergence of the Universe, but also the appearance of space and time themselves; therefore the questions of what lies outside the Universe, or what existed before it arose, are logically contradictory. [IMG_1] Fig. 2.4.1. Some stages in the history of life on Earth The question of what awaits the Universe in the future remains open. In time, which differs greatly among models, the Universe will cease to be a place suitable for life. It may collapse, degrade in endless expansion, or be reborn; for now the choice reflects scientists’ tastes and intuitions more than exact data. At least, the “essence” of the current stage in the development of the Universe consists in the existence of stars and galaxies within it. The entire history of the Universe known to us is the history of its expansion. During this expansion, elementary particles, atoms of hydrogen, and stars gathered by the force of gravity arose within it. In stars, matter reaches such a degree of compression and heating that thermonuclear reactions begin, that is, the fusion of nuclei of light elements. Thus the most widespread thermonuclear reaction in the Universe is the formation of helium nuclei as a result of the fusion of hydrogen nuclei. The fusion of nuclei of elements from the first half of the periodic table, up to iron, releases energy. This continuously released energy prevents stars from contracting. Any star, including our Sun, balances between two processes: gravitational contraction and expansion due to the release of thermonuclear energy. Stars in which all hydrogen has been “burned out” contract more strongly, and thermonuclear reactions involving the fusion of helium nuclei may begin within them. Thus, elements located in the periodic table before iron can be formed during thermonuclear reactions. But how do the elements of the second half of the table arise? Sometimes, as a star contracts, reactions begin in it that cause the amount of released energy to increase abruptly. Such a star explodes like a thermonuclear bomb and becomes a supernova. The matter of the supernova is scattered into space with colossal energy. How are heavy elements obtained in particle accelerators? Some nuclei are accelerated and used to bombard others. At sufficiently high collision speeds, nuclei may fuse into a single one. The same thing happens during supernova explosions. “Stars are a mechanism, a means of evolution, the result of which is the heavy elements” (V. Snytnikov, V. Parmon, 2004). ...When humankind obtains energy by conducting the nuclear fission reaction of uranium, it extracts energy accumulated during supernova explosions. Thus, for diverse elements to appear in the Universe, a certain period had to pass, sufficient for the birth and death of stars. The Solar System, the Earth, and even our bodies contain elements that passed through dead stars. The age of the Earth, and of the Solar System, is 4.6 billion years. The Sun and the planets formed from a gas-dust cloud that was the result of the destruction of previous stars. Nuclear transformations in earlier stars are the reason for the diversity of chemical elements on Earth, which makes life possible. At present the Sun is halfway through its lifetime. In roughly 5 billion years, it will first expand to the orbit of the Earth, then contract, and finally explode. New stars will arise from the resulting matter. On Earth, no rocks preserved from the time of its origin are accessible. However, its age can be inferred from the age of meteorites. These are fragments of Solar System “material” that did not become part of the planets. They continue moving through the Solar System and periodically fall onto the Earth’s surface. The most common meteorites are stony-iron meteorites. Very roughly, one may say that they consist of silicates, the “stone,” and metals, the “iron.” The density of the “iron” is greater. The Earth formed as a lump of such material. During collisions it heated up, and the denser material, the “iron,” moved inward, toward the planet’s center. The lighter substances, the “stone,” were displaced toward the surface. This released a significant amount of energy, and the Earth became strongly heated. As a result, the planet acquired a structure similar to the modern one: the core is surrounded by a viscous mantle, on the surface of which the crust floats. The movement of lithospheric plates, fragments of the crust, began. Mountains formed from their collisions. Sedimentary rocks arose as a result of the destruction of mountains and the transport of matter by water and air. The Earth’s surface cooled to a temperature below 100°C about 4 billion years ago. The origin of the ocean was associated with this. For roughly 800 million years afterward, the ocean remained very hot, above 90°C. The oldest minerals known to us on Earth are 4.2 billion years old, but they are not sedimentary. The oldest sedimentary rocks, from the Isua formation in Greenland, are 3.8 billion years old. They already contain traces of life, carbonaceous particles of biological origin. This means that life appeared on Earth as soon as conditions even somewhat suitable for it had arisen. The history of terrestrial life began in boiling water! 2.09. The Biogeochemical Cycle of Phosphorus
2.09. Biogeochemical cycle of phosphorus
D. Shabanov, M. Kravchenko. Ecology: The Biology of Interactions Chapter 2. Biospherology
2.11. (supplement) What Is Life?