He heliocentrism or heliocentric theory was an astronomical model that changed the dominant idea that the Earth was the center of the universe. In the heliocentrismo the central point happened to be the Sun, with the rest of the celestial bodies turning around. That's where his name comes from, because"helio"was the Greek name for the Sun.
Although already in ancient Greece there were authors who defended this idea -especially Aristarchus of Samos-, it was Nicolás Copernicus, in the sixteenth century, who propelled it. His astronomical studies convinced him that geocentrism did not explain the reality of the sky, which made him look for new possibilities.
In addition to placing the Sun as the center around which the planets revolved, the Polish astronomer indicated the order in which the planets were placed in the solar system. At first, the Protestant and Catholic churches did not accept that theory, since they said it was against the Bible.
Even Galileo Galilei , one of the scientists that in the XVII century continued with the works of Copernicus, had even to face an ecclesiastical judgment. Later there were other scholars who continued to observe the sky to shore up and improve the system proposed by Copernicus; they stand out among them Kepler and Isaac Newton .
History
Background
Although for centuries the dominant astronomical model was the geocentric, already in ancient Greece there were authors who advocated other alternatives.
Among them was Philolaus, a Pythagorean philosopher who claimed that in the center of the universe there was a great fire, with the planets and the Sun spinning around them.
On the other hand, Heraclides Póntico explained in the IV century a. C. that only Mercury and Venus revolved around our star, orbiting in turn around the Earth along with the other planets.
Aristarchus of Samos
This author is known to be the first to propose the heliocentric system. Aristarchus of Samos (c.270 BC), continued the work of Eratosthenes, who had calculated the size of the Moon and the distance that separates it from the Sun.
Ptolemy
Ptolemy has gone down in history as the creator of the geocentric theory, although previously Aristotle I had defended that model. In his work in the second century, Claudius Ptolemy concluded that the Earth was the center of the universe, while the stars and planets revolved around him.
The importance of this theory was such that it became the preponderant until the sixteenth century, when the heliocentrism was strengthened. Geocentrism was also the option defended by the Church, which considered that it adapted much better to the Bible.
Heliocentrism
As mentioned before, it was not until the 16th century that the vision of the universe began to change. The failures of the geocentric system to explain the celestial movements led the Polish Nicolaus Copernicus to develop a new theory. In 1543 he published the book De revolutionibus orbium coelestium , the one in which he published his postulates.
Among the advantages of this heliocentric approach was the best explanation of how the planets move, allowing to predict their behavior.
Reactions
The first reactions were not very favorable to the theses of Copernicus, especially from the religious sphere. The protestant churches affirmed that they did not adjust to which it appeared in the Christian writings and the own Luther reacted against the author of very negative form.
Years later, as early as 1616, it was the Catholic Church that condemned the theory. Copernicus' book became part of his list of forbidden books.
Who proposed it?
The author of the heliocentric theory, without taking into account the Greek background, was the Polish Nicolaus Copernicus. The astronomer came to the world in Thorn, on February 19, 1473.
His family was well-to-do and his uncle, an important bishop, made sure that he received the best possible education and sent him to the most prestigious universities.
Among these universities stands out the one in Krakow, in which Copernicus entered in 1491. There he began his career in Humanities. After this he moved to Italy, where he studied law and medicine. Finally, in 1497 he completed his training in Bologna, graduating in Canon Law.
What he could not finish was the Medicine career, although he practiced the profession for 6 years. In 1504 he was appointed canon of the Diocese of Frauenburg.
Investigation
The great majority of his astronomical observations were made in Bologna, being assistant to a professor at the university.
His first work on the subject was written between 1507 and 1515, and was published with the title Commentariolus ; it practically went unnoticed and very few copies were made.
In this work the heliocentric theory already appeared, although it did not contribute any type of mathematical demonstration. What was part of the book was the ordering of the planets with respect to the Sun.
His fame was increasing and Copernicus was one of the participants of the Fifth Lateran Council, which was convened in 1515 to reform the calendar.
Copernicus continued to improve his theory in a work that took him to 1530. Although he finished it that year, the work On the revolutions of the celestial bodies It was not published yet.
Publication
This did not prevent part of its content from leaking, reaching the ears of the Vatican. In 1533 the Church discussed its content and three years later the general procurator of the Dominicans encouraged him to publish it. In this way, a few days before his death, on May 24, 1543, Copernicus saw his masterpiece published.
To further assess their research, it should be noted that the means of astronomical observation of their time were very rudimentary. There was not even the telescope.
To study the sky Copernicus could only trust his eyes and spent countless hours at night in the tower of his house in the mountains.
Also, thanks to his great training, he devoted himself to study the classic works on the subject, in order to compare them with his own data.
Step from geocentric to heliocentric
One of the reasons that explains why the geocentric theory was in force so long was because of its simplicity. Facing the observer, it seemed logical that the Earth was the center of the universe, with the stars desorbitando around him. In addition, religious currents supported this system.
However, for many scientists the theory presented too many weaknesses. When Copernicus began to study the subject he found that geocentrism could not explain much of what was happening in the universe.
Hence, he began to develop his own vision. Part of the doubts that Copernicus had are reflected in his own words:
"[...] when a ship sails without shaking, the travelers see moving, in the image of their movement, all the things that are external to them and, conversely, they think they are immobile with everything that is with them. Now, in relation to the movement of the Earth, in a totally similar way, it is believed that the whole Universe is the one that moves around it [...]".
Mathematical failures of geocentrism
One of the aspects in which Copernicus was fixed at the time of studying the geocentric system was in the mathematical errors that it contained. These were reflected in lags in the calendar, which led to its reform in 1582 when the Gregorian was adapted.
The Polish astronomer participated in the meetings that, since 1515, were held to change the calendar. These were based on the astronomer's knowledge that the errors were due to the incorrect conception of how the celestial bodies moved.
Characteristics of the theory
In summary, heliocentrism can be defined as the theory that states that it is the Earth and the other planets that revolve around the Sun. The followers of the idea indicate that the Sun remains immobile in the center.
Postulates
In his work, Copernicus established a series of postulates that explained his conception of the universe:
- There is no center of gravity of the celestial spheres.
- Earth is not the center of the universe. It is only gravity and only the Moon revolves around it
- The spheres that make up the universe revolve around the Sun, this being the center of it.
- Established the distance between the Earth and the Sun, comparing it with the height of the sky.
- It is the Earth that moves, although it seems that it remains immobile.
- The sun does not move. It only appears, precisely because of the movement made by the Earth.
- It is enough to contemplate the movement of the Earth to explain the apparent anomalies in the universe. All displacement of the stars is apparent if we look at it from our planet. That is, they do not turn around, it just seems that way.
Specifications
Starting from these postulates, some characteristics of the heliocentric theory proposed by Copernicus can be extracted. He claimed that the universe was spherical, just like Earth was.
As for the movements of all celestial bodies, he established that it was regular and perpetual. He also described it as circular, dividing it into three different movements:
Daytime rotation
It is the rotation, only of the Earth, with a duration of 24 hours.
Annual translation
The one that develops the Earth when it revolves around the Sun for a year.
Monthly movement
In this case it is the Moon that moves around the Earth.
Planetary movement
The planets move around the Sun and, in addition, when contemplating it from the Earth it is necessary to add the terrestrial movement itself to calculate the effects.
On the other hand, Copernicus determined that the universe was much larger than Earth and, finally, left detailed the order in which the planets were located with respect to the star.
Order of the firmament
Starting from the Sun, which supposedly was the center of the scheme, Copernicus determined in what order all the planets that orbited it were placed. He did it following a spherical pattern, different from the one that was later fixed.
For Copernicus there was an immobile sphere in which were the fixed stars and within which our solar system would be found.
In any case, apart from his explanation of how the different spheres that made up the universe behaved, the proposed order began with the Sun, and behind it were Mercury, Venus, Earth and Moon, Mars, Jupiter and Saturn.
Copernicus also established the duration of the different translations of each planet, beginning with the 30 years of Saturn and ending with the 3 years of Mercury.
Other scientists who supported the theory and its ideas
Galileo Galilei
After the work of Copernicus was published, his theory still took a long time to be accepted. Many considered it contrary to the Bible and religious interpretations.
The invention of the telescope and its great improvement on the part of Galileo Galilei confirmed part of what was exposed by Copernicus. His observations confirmed what was written by the Polish scientist, but it did not help the authorities to accept it either.
Galileo had to face an ecclesiastical tribunal and was forced to retract his investigations.
Giordano Bruno
He was another of the scientists who supported the Copernicus theory. In addition, thanks to his research, he went a step further on what the Polish astronomer had claimed.
In the second half of the sixteenth century he came to the conclusion that the universe was much larger than Copernicus had said. On the other hand, he affirmed that there were innumerable solar systems apart from the terrestrial one.
Johannes Kepler
Kepler was one of the most important followers of heliocentrism. His work was about the planetary movement, trying to find some laws that would explain it. He went from defending the Pythagorean laws of harmonic movement to leaving them aside because he did not correspond to what he observed in the sky.
In this way, while studying how Mars moved, he had to recognize that it was impossible to explain his movements through the model of the harmony of the spheres.
However, Kepler's religiosity made it difficult for him to abandon that theory. For him the logical thing was that God had made the planets describe simple geometric figures; in this case, perfect polyhedra.
Having abandoned the polyhedrons, he went on to try various circular combinations, which also adapted to his religious beliefs. Faced with his failure, he tried it with ovals. Finally he chose the ellipses, publishing his three laws that describe the movement of the planets.
Isaac Newton
Already at the end of the seventeenth century Isaac Newton discovered the law of gravitation. This was fundamental to explain the forms of the orbits. With this, heliocentrism gained strength against other visions of the cosmos.
References
- Astronomy. Nicolaus Copernicus and the heliocentric theory. Retrieved from astromia.com
- EcuRed. Heliocentric theory. Retrieved from ecured.cu
- Barrado, David. When the Earth stopped being the center of the Universe. Retrieved from elmundo.es
- The Editors of Encyclopaedia Britannica. Heliocentric system. Retrieved from britannica.com
- Beavers, Bethany. Heliocentric Model of the Solar System Facts. Retrieved from sciencing.com
- Impey, Chris. Copernicus and the Heliocentric Model. Retrieved from teachastronomy.com
- Astronomy Education at the University of Nebraska-Lincoln. Heliocentrism. Retrieved from astro.unl.edu
- Rabin, Sheila. Nicolaus Copernicus. Retrieved from plato.stanford.edu