The universe has a beginning or a great explosion for its extension (Big Bang) and there is talk of an end (Big Crunch). But what happens in that period between the two Big? How has the universe been evolving before the arrival of the Great Collapse? There are so many testimonies and inquiries regarding these facts that what we usually know as the Cosmology.
What is Cosmology?
Cosmology is the science that experiences the origin and evolution of the Universe like an everything.
Theories And Historical Evolution Of Cosmology
El development of cosmology It has not gone hand in hand with experimental observation, since this is generally very complex to carry out, and only certain known facts are used to give arguments of excellence to an incredible theory that can be practically demonstrated to its last terms.
In this sense, at present, the experimentation, mainly the probes sent to the space and radiation that of the cosmos or the universe we grope on Earth, are inducing a golden age in cosmological theory, and once again events are ahead of us. Even so, humanity is aware and reasons that speculative part that is undoubtedly related to this part of Physics.
We can locate the beginning of Western Cosmology 2500 years ago, in the Greek era. It can be pointed out that the first great cosmological theory, which remained until the Renaissance, was protected by Plato and, above all, Aristotle, with its four elements, that is, earth, water, air and fire.
In addition to that enduring and perfect movement of celestial objects specified in eight rotating crystalline spheres, whose matter was the so-called quintessence. All induced by a Great Maker, with the Earth in the middle.
Likewise, the duration of this Aristotelian Cosmology can also be exposed by the ad hoc transformations made by the astronomer Claudius Ptolemy in order to explain the evident anomalies that were perceived in the movement of the stars (especially the retraction of the planets).
On the other hand, it was not until the year 1543 when Aristotle's geocentric model was transformed by the heliocentric model of the Polish mathematician Nicholas Copernicus, who precisely the year of his death announced his work on the revolution of the celestial spheres.
In this sense, these ideas were progressively consented and perfected by astronomers like the German Johannes Kepler to the new gravitational Universe of the Englishman Isaac Newton, which lasted until Albert Einstein expressed his theory of General Relativity in the XNUMXth century.
Finally, in the final stage of Cosmology the discourse has undergone an important change, that is, the knowledge of Universe on a large scale could not be separated from the study of physics of the smallest, it was necessary that Astronomy and Particle Physics went hand in hand to build any cosmological theory.
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The Cosmological Principle
El cosmological Principle, asserts that all fundamental observers observe the same cosmohistory. Similarly, this principle is opposed to the aforementioned "anthropic principles", where our perspective on the Universe would be privileged.
3 Data Regarding the Cosmological Principle
It is essential to know everything related to these observations in order to understand more easily the principle cosmological.
1. Direct Consequences
One of the direct consequences of the cosmological principle is to presume the equality and isotropy of Universe on a large scale. There is considerable observational suspicion that the structure of the Universe exhibits an extraordinary resemblance of matter and radiation on scales of 108 light years.
2. Robertson-Walker metric
The cosmological principle also heralds the geometry that we must use to measure distances and time intervals on this scale, and for this we must find the metric that governs this geometry on a large scale.
3. How to get the calculations?
These calculations are based on the Relativity Einstein General, but we must not leave aside the fact that everything is based in turn on the works of the great geometers, and apart from those of the father of geometry, Euclid, the works of the non-Euclidean geometries of the Germans Carl Friedrich Gauss and Bernhard Riemann, the Hungarian János Bolyai and the Russian Nikolai Lobachevski, in the XNUMXth century, were decisive. So let's see how the metric is derived.
It usually starts from the so-called Weyl postulate which assumes the similarity of the Universe as a substrate or perfect fluid in which the geodesics are orthogonal to a family of space-genus hypersurfaces.
That is, we will work with what is known as comoving coordinates, which are specified by the free falls of the essential observers, so that two geodesics do not intersect except at some singular point in the past or future.
If the fundamental observers coincide their clocks when for all of them the cosmological parameters they have the same values (temperature, average density, pressure, among others) the effective common time is what is known as cosmic time t, which will specify the simultaneity surfaces. The sketches of the parameters seen by the primordial observers is what we call cosmohistory.
Cosmology and the Big Bang
Even though the model of Big Bang or also known as the Big Bang, is a theoretical model observationally quite vigorous and generously accepted among the scientific community, there are some aspects that however remain to be resolved.
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6 Fundamental Studies Of The Relationship Between Cosmology And The Big Bang
Some of these studies are:
1. Ignorance of the Origin of Cosmology
It is unknown what happened in the early days after the Big Bang. The answer is investigated through the study of the early universe, one of whose goals is to find the explanation for a possible union of the four fundamental forces. These are: the strong nuclear force, the weak nuclear force, the electromagnetic force and the weakest of the four forces which is known as gravitational).
2. Failure of a Definitive Model
There is no definitive model of the creation of the current structures, starting from the Big Bang. The answer is sought by studying the production and evolution of galaxies and cosmic rise.
3. Doubt About The Big Crunch
It is not known what the terminable fate of the universe.
4. Dark Matter and Dark Energy
For the most part, the nature of the dark matter and dark energy.
5. Elementary Particles
In the moment after the Big Bang the elementary particles arose, the quarks up in protons and quarks down in neutrons, and the exact ratio of protons to neutrons is not known.
6. Constitution of Elementary Particles
Elementary particles are created by two quarks with the same electrical charge, they would not have been able to couple thanks to the electromagnetic interaction, it is useless to go to the strong nuclear interaction.
Well, this only has a transcendence of the maximum size of a atomic nucleus and also because the electromagnetic interaction has an enormous scope and if the universe was enlarged in a single second a hundred octillion times, in this temporary period of time the strong nuclear interaction could not assemble almost all (if not all) of the quarks.
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In conclusion, Cosmology is a branch of the Physics that has many questions, and in my opinion, I consider that there are still many studies to apply to continue nurturing this science.