Cosmology as a science is aimed to study large scale properties of the Universe as a whole mega-structure. Applying various scientific methods and approaches to understand the origin, evolution and ultimate fate of the entire universal world in all its variety and complexity this field of science involves a formation of theories and hypotheses about the global nature which tend to make different predictions for phenomena that can be tested and verified with physical observations and mathematical calculations. The long history to comprehend the Universe in its totality and intrinsic constituent components is associated with an origin and evolution of such intrinsic elements of life as religion, art, science and philosophy which complement in a harmonious way the cosmology as a branch of study and make it a unique science combining and using their achievements over the historic development of a mankind within the last 2 million years. In a plain language cosmology is just a fascination of people with the skies and their ultimate dream and a long-cherished desire to realize their proper meaning and place in the Universe.

This interest in the skies was probably inspired and generated more or less systematically about 7,000 to about 2,500 years ago with the ancient Babylonians who lived in the area of present day Iraq between the Tigris and Euphrates rivers where the two join the Persian Gulf and who were quite skilled astronomers and learnt to predict apparent motions of the Moon, stars, planets and the Sun upon the sky trying to find answers to the fate and glory of people. But it was really the ancient Greeks in the fourth century B.C. who for the first time developed a cosmological model within which to interpret these motions stipulating that all stars were fixed on a celestial sphere which was rotating about the spherical Earth every 24 hours and planets, the Sun and the Moon moved in the so-called ether between the non-flat Earth and stars. This particular model of cosmic structure was further perfected in the following few centuries, culminating in the second century A.D. with Claudius Ptolemy’s successful but complicated geocentric system that prevailed for 1,400 years and stated according to this most influential of Greek astronomers and geographers of his time (living about 85-165) that perfect motion of all cosmic bodies around the Earth should be in circles with a minor exception for the complicated movements of planets which appeared to periodically loop back upon themselves. To explain this phenomenon he introduced epicycles so that planets moved in circles upon circles about the fixed Earth.

Then in the 16th century Nicolaus Copernicus – a Polish astronomer and mathematician who was a proponent of the view of the Earth in daily motion about its axis and in yearly motion around a stationary sun – put forward a heliocentric system where the Earth in conjunction with the other planets of the Solar system rotated along a circular orbit about the Sun. However contrary to his brilliant model all observational evidence of that time favored the old Ptolemaic system because back then astronomers failed to record shifts , or parallax, in relative positions of stars from different parts of our planet’s orbit. This mystery was later solved by Tycho Brahe, a Danish astronomer who is best known for the astronomical observations which led Kepler to his theories of the Solar system . He assumed in this regard that stars visible on the night sky should be tremendously distant which prompted the idea of a limitless Universe. But only first Galileo Galilei (1564-1642) with his telescope and later Johannes Kepler (1571-1630), a German mathematician, astronomer and astrologer as well as a key figure in the 17th century astronomical revolution, managed to create a heliocentric model of the Universe based on their astronomical discoveries and mathematical calculations. The planets turned out to move in ellipses, not perfect circles, about the Sun within one well-organized system. Meantime an Englishman Isaac Newton showed that elliptical motion could be explained by his inverse-square law for the gravitational forces. The cosmos seemed to be an infinite and eternal sea of stars, each much like our own Sun, existing according to its own laws and keeping many mysteries which were hidden from a naked eye of a human being.

Finally in the 19th century the German astronomer and mathematician Friedrich Bessel measured the distance to the nearest stars by parallax which turned out to be about 25 millions of million miles away. For comparison the Sun is just 93 million miles away from our planet Earth and makes one rotation about the center of the galaxy every 250 million years. In fact, most of the visible stars on the sky are located in our galaxy called Milky Way which is a lens shaped, flat “island universe” and beyond which there are 200 billion other galaxies. This hypothesis was only proved to be a reality in 1920’s by the American astronomer Edwin Powell Hubble who found similar in size and structure distant galaxies in other nebulae and discovered that those galaxies were moving away from us. It was quite inexplicable until the era of Albert Einstein who formulated the General and the Special Theories of Relativity in the beginning of the 20th century and made a revolution in a cosmology and physics proving an expansion of the Universe. It is not contracting under the gravity and matter is not falling into a singularity due to the existence of a cosmological constant or dark energy which could balance the gravitational forces, keep galaxies apart and prevent the Universe from being static. Today we know quite a lot about matter, dark matter and dark energy which together are called the cosmic triangle that in its turn helps people understand the very nature of their existence and genesis.

The instant moment of a creation is called the Big Bang which occurred 13.7 billion years ago and is continuing even now because matter is still traveling after the initial burst and we still find traces of a primordial fireball in different parts of the Universe. This point of genesis was predicted by the Russian mathematician and physical scientist Alexander Freidmann in 1917 based on the Einstein’s famous equations and was coined the Big Bang by the British astronomer Fred Hoyle. In fact, cosmology, whether classic or quantum, is the only science which is closely connected in many ways with religion and philosophy (for instance, it relates to causality and freedom as well as a gnosticism, materialism, dialectics and idealism from the philosophical point of view as well as theism, deism and atheism from the point of religion) because it describes from the pragmatic and scientific points of view the same milestones in the history of life such as genesis, cosmic evolution and natural variety, laws of nature and a compositional structure of the Universe. People invented and imagined God in their passionate and sincere strive to explain their life in its totality and complexity and still strongly believe in His existence due to the inability of science to give reasonable and feasible explanations and postulations of a great variety of natural phenomena despite a dramatic increase in the volume of available knowledge accumulated during the last 200 years of scientific and industrial revolution. The more mysteries of the Universe are solved, the more questions are still remained unanswered. Probably one day the humans will approach God so close that they will finally realize and grasp its Holy spirit, meaning and nature first and foremost in themselves as unique creatures of God and will crack this divine jigsaw of a universal harmony which must and will dominate the world in general and in particular , being one of its major, topmost principles. These issues and concepts concerning theism, atheism and cosmology are extensively tackled by cosmologists and philosophers among whom are Pythagorus, Nostradamus, Mikhail Lomonosov, G.W. Leibniz, Richard Swinburne, Adolf Grünbaum, Stephen Hawking, Ned Markosian and many others.

The confirmation of the facts that the Universe was not static and would be expanding eternally came with the Steady State model when in 1965 Penzias and Wilson discovered a cosmic microwave background radiation of such light elements as hydrogen and helium that was interpreted as the faint afterglow of the primordial fireball, which had been predicted in the works of Gamow, Alpher and Hermann even back in 1949. As a result of all these developments since the 1970’s almost all cosmologists have come to accept the Big Bang model by including in their more specific, but still fundamental agenda certain questions and problems concerning a structural composition of matter, a formation of galaxies, a functioning of black holes, a dark energy and an invisible dark matter, an anti-matter, positive and negative charge, parity and time forms of existence, space-time curves, pulsars and neutron stars, string channels between multi-verses in the one and only Universe, alien forms of life and planet formation on a macro level as well as particles and fundamental sub-particles like WIMPs, Higgs and muons in a micro world. Therefore, nowadays cosmology has become closely associated with quantum and particle physics, relativity, mathematics, astronomy and astrophysics.

We are now much advanced in finding answers to some of these questions with a discovery of the cosmic microwave background radiation and a detection of anisotropies and slight temperature fluctuations in this radiation which could be a seed material for galaxy formation. The Hubble Space telescope, The International Space Station, The CERN Large Hadron Collider, The Tevatron at Fermi Laboratory and different deep space satellite missions give us an ever improving picture of our Universe, inspiring theorists to produce even more daring and sometimes extravagant models, drawing upon the latest ideas in relativity and particle physics. Thus, cosmology as a study of cosmos and its origin and evolution brings us to a more comprehensive realization that we could never know with an absolute certainty where the Universe came from or why anything at all should ever exist. Nevertheless studying cosmos offers clues which either confirm, eliminate or strengthen various theories and hypotheses. In short cosmology is the study of the physical Universe considered as a totality of phenomena in time and space.