The evolution of the universe
Our universe is considered to have originated some 14 and 15 billion years ago and nowadays every time we continue studying the universe it is more complex to understand it, but we are sure of something that it must have originated, the same as it is explained with the most accurate and accepted theory to date that is the Big Bang and that from that moment on has been evolving to what we know these days.
But to start we must know about the theory of the Big Bang that gave rise to our universe, the same that is defined: that our universe was created from the nothingness in which all the matter, energy, space, time of the universe in that moment was too concentrated in an extremely small area, thus possessing an unimaginable density and heat causing it not to bear until in a certain time "erupted", after that time the universe was a dense opaque and expanding plasma; with radiation that could not get out, and with the formation of hydrogen atoms. From there, as the temperature goes down, gas clouds form hydrogen atoms, and those clouds begin by gravity to become stars and then in galaxies (Wald, 1998)
The stars also have their cycle of evolution and they go from a gas of atoms of hydrogen that is compressed by the force of the gravity, this gas then forms a ball that heats up as it is compressed. The gradual increase in temperature then allows nuclear reactions to begin. When these gas balls balance the radiation and gravity pressures, they acquire a stable spherical shape and give rise to a new star, the same ones that spend most of their lives radiating and in balance - in the so-called main sequence consisting of in which the stars of this sequence are those that use hydrogen fusion in helium as a source of energy - this source can be terminated depending on two factors: the amount of hydrogen available at its center and the speed at which that fuel burns. The first quantity is proportional to the mass of the star. The second parameter is linked to the energy produced by the star, therefore, to its brightness, therefore the luminosity is simply proportional to the mass, but it increases much faster, that is, the more mass a star has, the more it burns. fast its fuel, and until it runs out of nuclear fuel and can explode as a super-nova (if its mass is large) or end up as a white dwarf (if its star mass is small). From the remains of super novae this new gas expelled by the star can generate other stars, that is, a new cycle of star formation begins. (Bennett, 2005)
At present, the best models of galaxy formation are the so-called hierarchical models. Where the structures of galaxies, and the cosmos are produced by mergers of minor objects such as the grouping of stars, celestial bodies and cosmic matter that is concentrated in a certain region of space due to gravitational attraction and constitutes a unity in the universe. (LIPARI, 2005)
And going back to the universal process of death and rebirths from which we emerged. The sun was formed 4.65 billion years ago was born from clouds of gas and dust that contained residues of previous generations of stars, during the collapse of the primordial gas cloud, gravitational energy became thermal, which produced an increase of the temperature inside the nebula. And at these temperatures, the dust grains decomposed into molecules and atomic particles, in which the contraction period of the term cloud gave rise to the Sun.
The history of the Earth comprises approximately 4,570 million years, from its formation starting from the protosolar nebula, which is that the solar nebula rotated slowly at its origin. This solar nebula was condensed as it cooled and gradually flattened by the combined effect of the forces of gravity and centripetal forming with time, the central star and the planets.
After what happened the planet Earth was an incandescent mass, the temperatures close to 5000ºC, composed of gases, liquid and viscous substances that mainly contained hydrogen, carbon, silicon and iron, the last one that was located in the center of the planet. being heavier, after cooling the surface caused the solid outer layers, but the heat from the interior fused them again. Finally, the temperature dropped enough to allow the formation of a stable earth crust.
At first it had no atmosphere, and received many meteorite impacts. The volcanic activity was intense, which caused large masses of red hot lava to go outside and gradually increase the thickness of the crust as it cooled and solidified. This activity of volcanoes generated a large amount of gases that ended up forming a layer on the crust. Its composition was very different from the current one, but it was the first protective layer and allowed the appearance of liquid water. (SAGAN, 1996)
In the eruptions, water vapor was generated from oxygen and hydrogen, which, when ascending through the atmosphere, condensed and speculated that the fusion of atoms in the atmosphere; then the ultraviolet light was assembled in amino acids and fatty acids. Same molecules that have been detected throughout the universe and form the basis of DNA. Then these molecules fall with the rain in swamps, and it is there that the clay allows to form the nucleic acids and the DNA, thus giving origin to the primitive life in the sea.
So from that moment the first cyanobacteria and plants were created 3500 to 4000 million years ago and these were evolving until 1000 million years ago the first multicellular animals appeared, which changed in time until 200 million years ago that the first mammals and dinosaurs appeared, the same ones had their extinction millions of years later, those that survived were very few mammals that from there, already 30 million ago the monkeys and anthropoids appeared. And from here it has been studied through the natural selection proposed by Darwin that explains the origin of the diversity and the adaptation that each of the species were subjected to which evolved until now to have those that we know including that of the human being. (LIPARI, 2005)
Where are we from? Then we are those atomic particles of the whole universe, which were evolving unchained other events necessary to form the atoms. It is so fascinating that life has happened from the necessary combination of these events, since we are nothing more than the set of many atoms of different elements arranged in the exact form, then I affirm that we are not from the place where we were born or live but rather we are from where we come from a single and common Universe that created us.
Bibliography
Bennett, J. (2005). The Essential Cosmic Perspective. Addison-Wesley: Massachusetts.
LIPARI, S. (2005). EVOLUCIÓN EN EL COSMOS:DEL BIG BANG A LA VIDA-CONCIENCIA. EVOLUCIÓN EN EL COSMOS:DEL BIG BANG A LA VIDA-CONCIENCIA, (págs. 38-39). Córdoba.
SAGAN, C. (1996). Un punto azul palido.Una vision del futuro humano 2. Barcelona: Planeta.
Wald, R. M. (1998). Espacio, tiempo y gravitación: la teoría del Big Bang y los agujeros negros. Chicago: Fondo de Cultura Economica.