Astronomy and the study of the universe

Meaning of astronomy


Traveling beyond a simple definition found in a general dictionary, we can find that in astronomy scientists and researchers are responsible for permanently analyzing the characteristics and movements of the stars that reign space Outside.

To those twinkling white dots that we observe in the dark skies cleared on any night of our lives are called stars; All of this comprises planets, stars, asteroids, satellites, nebulae, etc. that are the subject of tireless study for their description and follow-up and to determine their influence in our galaxy.

The first authors who were recorded in the history of the first studies in astronomy are for example Galileo Galilei, Nicolás Copernicus, such of Miletus or Aristotle, of which we will speak later to investigate in relation to their active lives that They were fundamental pillars in this branch of science.

But continuing with the definitions, meanings or origin of astronomy, we also get that since ancient times man has been curious anxious to discover how mysterious is represented in the universe and its components, both for its Distance as by the infinite variety of cosmic elements where none have similarity to the other but are influenced by their energies or the same orbits.

This discipline allows the individual to know what is beyond his or her eyes that is called as unknown and gives them the faculties to distinguish between each other in order to assign decisions, classifications, categories, among other guidelines.

To all this previously mentioned like planets, satellites or Nebulas is assigned the category of celestial bodies and astronomical objects that possess characteristics and physical forms prone to be studied continuously and then obtain the data and Records to be documented and to handle information more accurately for future research, or simply to conduct discussions, conversations, lectures, among other activities; This is achieved by astronomy.

The study of electromagnetic radiation turns out to be one of the main tools of knowledge for astronomy. For this purpose, the use of telescopes to allow the observation of these elements in the space for their comprehension and subsequent study is essential.


This information that provides us the results of the electromagnetic radiation on the observed stars translates as one of the missions of astronomy, because all these descriptions will lead to the realization of the various laws that govern the Universe that Ser’na determinants in any aspect.

Astronomy is also called as an activity in modern science that has played an important role for the evolution of man since time immemorial, mentioning the first civilizations that have had contact with this science and that each one in his Period has provided you with new lines.

Etymology of astronomy

This word etymologically is of Latin origin under the denomination astronomy and also emerges from the Greek composed by Astrón, or Astro and Nomo which means laws or norms. masculine noun. In the principles of humanity astrology was the predominant science considering that the primitives were governed by loas movements and behaviors of the Stars for their coexistence on earth and related to the periods of hunting and fishing or agriculture For food, and depending on the abundance or scarcity was related to the culmination of the productive periods.

This is not to say that there was an encroachment by a pseudoscience, but that there were simply no thinkers with scientific knowledge to elaborate investigations or observations without linking with horoscopes or calendars. The first scholars of the stars did so for the practical purpose of getting to establish measures in time and their cycles to be able to sow at the ideal time and foresee natural phenomena even.

History of Astronomy

Starting with a historical principle, we will begin this tour by the authors, as in previous paragraphs we had mentioned, but we must first mention that astronomy exists from the very birth of humanity, that is, primitive men felt A great curiosity to be surprised by the deep, wide and wonderful sky that comprised the universe and its objects when they looked at the dark space full of dots distributed everywhere.

Many were the centuries when the instruments for observing these phenomena were used in the firmament that laid the foundations of astronomy and which approximated the first explanations about the universe. This science arises when humanity abandoned the nomadic practices, to catch up with the evolutions, taking the first steps to the investigations of the stars.

At the same time the development of the human being began the empirical calculations with the exploitation of the climatic changes, the periods of hunting and fishing, the culmination of the nights and the changes of season each year; Situations that depending on the abundance or shortage of food disposal could determine the actions to take for survival. These were the first tasks practiced in astronomy without tools or materials.

This type of activities that conjugated the daily work of primitive man with the positions of the moon the sun and the changes of season were so useful through the observations that confirms the evidence that the astronomy is one of the oldest occupations.


Besides this was something that the man with his short mind and scarce knowledge could not explain, but began to believe that in the firmament there were gods to which they were to be worshipped and to be thankful for the abundances with the food and favours to humanity as well as the Behaviour of the stars, and also avoid punishments

In the following video are narrated some actions of the men in the prehistory that carved the stones with shapes, figures of animals, tools of work and an endless number of signs that even the position in which they pointed was in direction towards a cardinal point Interesting that much might give reason that something they wanted to leave as a legacy.

The French researcher Chantal Jegues in this case moved to the Dutch Alps and went into the mountains looking for a response and try to validate a hypothesis that wanted to expose to the rest of his colleagues and was that in the works carved in the stones to Ntepasados wanted to develop a celestial map for productive use of humanity. Their astronomical calculations must take force to convince other investigators. See.

This kind of activities in which the venerations began to the gods that lived in the firmament, according to the prehistoric ones remained for many centuries because the practitioners of the cult were sure that the stars governed the destinies of the communities, without However, the scientific and technological advances were clarifying panoramas and contributing data of phenomena that at first were incomprehensible, this through calculations and the trajectories and behavior of the stars.

Ancient astronomy: Early astronomers and their contributions

The appearance of the night sky was not the same throughout the year, some stars were only visible in summer and others only in winter. If they looked at the apparent position of Sunrise I found the same position in relation to the stars, it was clear that this position was not fixed but slowly changed from one day to the next.

The ancients had understood that this movement was linked to the cycle of the seasons. After a complete cycle the sunrise found the same position in relation to the stars. The phenomenon made it possible to create an extremely useful, accurate and reliable timetable for agriculture that allowed the most favorable period for seeds and crops to be anticipated.

Authors of the first theories on the astronomy



One of the first data that was welcomed by humanity by the explanations with accurate arithmetic calculations was the scientist Aristarchus of Samo (310 BC.-C 230 A-c). It was a Greek astronomer and mathematician who proposed the theory that the earth and planets move around the sun, known as the Heliocentrico model. Aristarchus was the first person who met or assumed the challenge of manifesting a theory seg; his knowledge or studies also added to his hypothesis that the sun is much larger than the Earth, this succeeded after studying the distance and size of the sun.

This scholar of science supported his theories and was documented in the Royal Library of Alexandria, probably the largest in the world at that time in Greece, but many of his works were lost in the fire in the same institution, and now his Legacies we only have quotes in books or writings from other astronomers.

Eudox de Cnidus

After this in the arena appears Eudoxus of Cnidus that proposed the geocentric model and invented the celestial sphere, which was uin apparatus without defined radio concentric with the globe in which the stars seem to move and that allows in turn to represent the Direction in which the celestial objects are. Its movement is apparent and is determined by the movement of rotation of our planet on its own axis. The rotation of the Earth in the west-east produces the apparent movement of the celestial sphere in the east-west direction.

In addition to this, he was the first to propose a planetary model based on a mathematical model that catapulted him to be catalogued as the father of mathematical astronomy. Another of his theories was the cosmological model that affirmed that the Earth was the center of the universe and the rest of the celestial bodies surrounded it fixed in a total of 27 spheres gathered in seven groups.

However, none of his theories raised to the present day, that is to say, the data that are handled of his actions in those times only have through quotations in writings, poems and documents.



Another of the thinkers that operated at that time related to the first findings of astronomy was Aristotle. He was a philosopher, a logical scientist whose theories have influenced importantly in the intellectual history of the West for more than two millennia. He was recognized as the founding father of Logic and biology and his first systematic research on these two areas made them on previous reflections and writings.

One of his contributions was the theory of spontaneous generation; Biological theory that maintained that certain forms of life arise spontaneously from organic or inorganic matter or its combination. Tale’s belief was supported by Descartes, Bacon or Newton, but refuted by the scientific community and in the hands of Louis Pasteur was the answer that showed that this theory was a fallacy, exposing the Biogenesis law that every living thing comes from another living being.

Claudio Ptolemy

This character was a chemist, astronomer, astrologer and mathematical geographer Greco Egyptian who studied the large number of objects in the movement of the planets in order to build a geometric model that explains those positions in the past and Have the ability to predict future positions.

His model of the universe was his fundamental contribution. He brooded that the earth was motionless and occupied the center of the universe and that the OS, the moon, the planets and the stars revolved around him. Among his tasks was also to solve geometrically two major problems of planetary movement, which was the retrogradation of the planets and their increase in luminosity while retrograding and the different duration of the sidereal revolutions.

He was the creator of the horoscopes; He studied the sciences of astronomy and astrology and also dabbled in the field of optics by exploring the properties of light related to refraction and reflection by applying mathematical theories, which are now used for observations with Telescopes.

Tales of Miletus

Another of the great scientists recognized in the ancient astronomy was such of Miletus, mathematician, geometric, physicist, philosopher and Greek legislator to whom it is attributed important contributions in the field of philosophy, mathematics, astronomy and physics.

The scholars of those days affirm that there was no written theory of such, but it claims that this scientist used a method of comparison where the shadows served him to measure the height of the Egyptian pyramids. He realized that he could measure the height of these pyramids accurately by measuring the shadow of these at the time of day when the shadow was more or less equal to the size of his body.

He was often called the initiator of Greek philosophical and scientific speculation, but his contributions are surrounded by great uncertainties. Their philosophy is not known first-hand because no writing has been revealed about their activities. Their alleged claims may have been transmitted second-hand or even orally.

Other data on the evolution of astronomy


In the beginning of humanity, as we have explained so far, astronomy was reduced to the observations and prediction of the movements of the stars or objects visible to the naked eye without having any reaction with the physics. Greek culture was undoubtedly the first to make great contributions to matter as the definition of magnitude while pre-Columbian astronomy managed calendars accurately.

Between the 16th and VXII centuries, important contributions were obtained in the astronomical theme, such as the incorporation of the telescope by Galileo Galilei, which gave precision to the observations of the stars and in turn aroused new questions that, with the passage of time, They were finding the answers, therefore, there is no empty space in the universe and therefore no human being would let go of detail without first figuring out the development and the end, the quality of researchers.

Galileo also advanced in the determination of the lunar phases, movement of the planets, the principle of gravity that is the force that governs the movement in our universe.

From this point begins to measure the scope of astronomy as a fantastic development adding related disciplines to continue the path of knowledge.

Position astronomy

This theoretical part of the astronomy situates in the celestial sphere the position of the stars measuring certain angles with respect to some fundamental planes using for IT system of astronomical coordinates. It is the oldest branch of science that describes the movement of the stars, planets, satellites and phenomena, as well as the daytime movement and the annual movement of the Sun and the stars and is the one that is in charge of studying or measuring the positions, parallaxes and movements of its own. of the stars. To understand a little bit this definition we describe that Parallax refers to the angular deviation of the apparent position of an object depending on the point of view chosen.

It refers to using the position of the stars to develop a model of their movement or define the concepts used. Some of its objectives are:

Situate in the celestial sphere the position of the stars measuring certain angles with respect to fundamental planes.
Describe movements of stars, planets, satellites and phenomena such as eclipses and transits of planets by the disk of the sun

As for this topic of astronomical coordinates, it turns out to be one of the great problems that tries to solve the position astronomy because it consists fundamentally in determining the positions that occupy the stars in the firmament regardless of the Enormous distance in which they are found. For example, given the small length of terrestrial radio compared to such distances it is feasible to identify the land from a point in space, where the positions in which observers can be considered to be concides. This point is taken as the center of the celestial sphere on whose surfaces the apparent positions of the stars are located.

Although the scope of the vision of the observer is unable to appreciate the relative distances that separates them from the stars, it distinguishes the points of intersection of the spherical surface with the visuals directed towards the different celestial bodies and can calculate its Angular distance.

In addition this part of astronomy is used by scientists to describe mathematical structures present in processes that occur in the cosmos, such as the formation of galaxies, evolution of stars, and relativity, dealing in parallel with The search for answers to issues and issues that were still unfinished, such as the possibility of life on other planets.

Physical astronomy

More commonly called astrophysics is the term used to study physics applied to astronomy and is used to explain the properties and phenomena of stellar bodies through laws, formulas and calculations. This arose from the need to develop and relate the physical issue to the observations made to the stars so it was equivalent to the use of astronomy with physics generating the fusion forced. This method is based on the assumption of the physical and chemical laws applied in everything and for the whole universe.

These two terms are intimately linked, considering that each Astro has a physical component that determines its category and authentic characteristics, where it is used in this case the photometry where the brightness is measured.

This experimental practice is based on the observations and formulates hypothesis about physical situations not directly accessible, studying in addition the composition and structure of the interstellar matter, like for example the clouds of gas, dust that occupies extensive Zones in the universe that at one time were considered empty.

His research methods are also used in the study of the planets and bodies less of the solar system whose composition and structure has podium achieve the deep knowledge that in most cases has allowed to modify theories made by the First scientists.

It is the modern part of the astronomy that was only possible its beginning in the nineteenth century because through the spectra one could find out the physical composition the stars.

Areas of study of astrophysics

Astrophysics as we have described above is a discipline that mainly deals with the study or analysis of luminosity, weight, density, temperature or chemical composition of the stars, and has some main areas of study that would be Important to mention below:


It is a scientific discipline of the branch of biology that makes use mainly of a combination of the disciplines like astrophysics, biology and geology for the analysis of the existence, origin, presence and influence of the life in the whole of the universe Including the Earth.

Stellar Astrophysics

It is about the study of the Physics of the stars, their formation, evolution, finality, properties and distribution, indispensable to advance in our knowledge of the universe.

Galactic Astrophysics

It is the method used to study the physical characteristics of galaxies, for example the Milky Way. In this, astronomers use X-ray observations to see through the dark clouds of gas and dust and get the necessary information.


It is the science that studies everything related to the cosmos and the universe. It is the study of the origin, evolution and destiny of the universe using the terrain models of physics.


It is also called planetary science and is the whole of interdisciplinary matter involved in the study of planets or planetary systems including the solar system. He studies objects ranging from meteor to gas giants that exceed Jupiter’s size by five times.

Modern astronomy


The astronomical activity usually consists of investigating the celestial bodies and the way of executing such action shows different aspects being the most relevant the observation of the Stars, which is the practice that has been carried out since remote time when the Prehistory up to the present day with the incorporation of instruments and telescopes of advanced caliber to obtain the necessary precision.

Modern astronomy comprises different specials according to the divisions described below:

By the objects of study. Here are the comet specialists, differentiated for example from those who dedicate themselves to stars.

By the modality or technique empelada to carry out this study. In this part they are distinguished from the radioastronomers who use Radiotelescope antennas to gather information from the stars.

By the aspect chosen for that study. Here Aparace a subdivision that has to do with the objective of studies of the stars. A star can be observed to know its age and its chemical composition or simply to determine its position in the sky and then be used as reference.

Modern Astronomy Specialties

Among the specialties of modern astronomy are handled several lines that will breakdown below:


It is the study of the position of the objects in the sky and their change of position. It defines the coordinate system used and the kinematics of the objects in our galaxy.

Celestial mechanics

This part of the science is intended to interpret the movement of the astronomy of position in the field of the part of the physics known as mechanics, generally the Newtonian, which is the law of universal gravitation. It studies the movement of the planets around the sun, its satellites, the calculation of the orbits of the kites and asteroids.


This part of science, as we have already described in previous paragraphs, is about the physical study of the universe including the properties of astronomical objects.