HELIOCENTRISM: HISTORY, WHO PROPOSED IT, CHARACTERISTICS - SCIENCE - 2025

The heliocentric or heliocentric theory was an astronomical model which changed the dominant idea advocated that the Earth was the center of the universe. In heliocentrism the central point became the Sun, with the rest of the celestial bodies rotating around it. Hence its name, as "helium" was the Greek name for the Sun.

Although in ancient Greece there were authors who defended this idea -especially Aristarchus of Samos-, it was Nicolás Copernicus, in the 16th century, who promoted 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 rotate, 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 this theory, as they said it was against the Bible.

Even Galileo Galilei, one of the scientists who continued the work of Copernicus in the 17th century, even had to face an ecclesiastical trial. Later there were other scholars who continued observing the sky to prop up and improve the system proposed by Copernicus; Kepler and Isaac Newton stand out among them.

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 at the center of the universe there was a great fire, with the planets and the Sun revolving around it.

For his part, Heraclides Ponticus explained in the 4th century BC. C. that only Mercury and Venus revolved around our star, orbiting in turn around Earth along with the other planets.

Aristarchus of Samos

This author is known for being the first to propose the heliocentric system. Aristarchus of Samos (c. 270 BC), continued the works 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 geocentric theory, although Aristotle had previously defended that model. In his work done in the second century, Claudius Ptolemy concluded that the Earth was the center of the universe, while the stars and planets revolved around it.

The importance of this theory was such that it became prevalent until the 16th century, when heliocentrism took hold. Geocentrism was also the option advocated by the Church, which considered it to be much better suited 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 Nicholas Copernicus to develop a new theory. In 1543 he published the book De revolutionibus orbium coelestium, the one in which he made his postulates public.

Among the advantages of this heliocentric approach was the best explanation of how the planets move, allowing their behavior to be predicted.

Reactions

The first reactions were not very favorable to Copernicus's theses, especially from the religious sphere. The Protestant churches claimed that they did not conform to what appeared in the Christian scriptures and Luther himself reacted against the author in a very negative way.

Years later, as early as 1616, it was the Catholic Church that condemned the theory. The book of Copernicus became part of his list of prohibited books.

Who proposed it?

The author of the heliocentric theory, without taking into account the Greek antecedents, was the Polish Nicholas Copernicus. The astronomer came into the world at Thorn, on February 19, 1473.

His family was quite wealthy and his uncle, an important bishop, saw to it that he received the best possible education and sent him to the most prestigious universities.

Among these universities, the one of Cracovia stands out, 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 a career in Medicine, although he did practice the profession for 6 years. In 1504 he was appointed canon of the diocese of Frauenburg.

Investigation

The vast majority of his astronomical observations were made in Bologna, as a professor's assistant at the university.

His first work on the subject was written between 1507 and 1515, and was published under 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 provide any kind of mathematical proof. What was part of the book was the arrangement of the planets with respect to the Sun.

His fame was growing, and Copernicus was one of the participants in 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 until 1530. Although he finished it that year, the work On the Revolutions of the Celestial Bodies was not yet published.

Publication

This did not prevent some of its content from leaking, reaching the ears of the Vatican. In 1533 the Church discussed its content and three years later the Dominican attorney general encouraged him to publish it. Thus, a few days before his death, on May 24, 1543, Copernicus saw his masterpiece published.

To further value his research, it should be noted that the means of astronomical observation of his time were very rudimentary. There was not even the telescope.

To study the firmament, Copernicus could only rely on his eyes and spent countless hours of the night in the tower of his home in the mountains.

Likewise, thanks to his great training, he devoted himself to studying the classic works on the subject, in order to compare them with his own data.

Step from geocentrism to heliocentrism

One of the reasons why the geocentric theory was in force for so long was its simplicity. Looking at the observer, it seemed logical that the Earth was the center of the universe, with the stars exiting around it. Furthermore, religious currents supported that system.

However, for many scientists the theory had 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 smoothly, travelers see moving, in the image of their movement, all things that are external to them and, conversely, they believe they are motionless with everything that is with them. Now, with regard to the movement of the Earth, in a totally similar way, it is believed that the entire Universe is moving around it.

Mathematical failures of geocentrism

One of the aspects in which Copernicus paid attention to when studying the geocentric system was the mathematical errors 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, as early as 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. Followers of the idea indicate that the Sun remains immobile in the center.

Postulates

In his culminating work, Copernicus established a series of postulates that explained his conception of the universe:

- There is no center of gravity of the celestial spheres.

- The 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 so, precisely because of the movement that the Earth makes.

- It is enough to contemplate the movement of the Earth to explain the apparent anomalies in the universe. Any displacement of the stars is apparent if we look at it from our planet. I mean, they don't revolve around it, it just looks like it.

specs

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 the heavenly bodies, he established that they were regular and perpetual. He also described it as circular, dividing it into three different movements:

Daytime rotation

It is the rotation, solely of the Earth, with a duration of 24 hours.

Annual translation

The one that the Earth develops by revolving around the Sun for a year.

Monthly movement

In this case it is the Moon that moves around the Earth.

Planetary motion

The planets move around the Sun and, in addition, when contemplating it from Earth, the earth's own movement must be added to calculate the effects.

On the other hand, Copernicus determined that the universe was much larger than Earth and, finally, detailed the order in which the planets were with respect to the star.

Order of the firmament

Starting from the Sun, which was supposedly the center of the scheme, Copernicus determined in what order all the planets that orbited it were placed. He did it following a spherical scheme, 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, the Earth and the Moon, Mars, Jupiter and Saturn.

Copernicus also established the duration of the different translations of each planet, starting with the 30-year Saturn and ending with the 3-year Mercury.

Other scientists who supported the theory and its ideas

Galileo Galilei

After Copernicus's work 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 by Galileo Galilei confirmed part of what Copernicus said. His observations confirmed what was written by the Polish scientist, but neither did it help the authorities to accept it.

Galileo had to face an ecclesiastical court and was forced to retract his investigations.

Giordano Bruno

He was another of the scientists who supported Copernicus's theory. In addition, thanks to his research, he took one step further on what the Polish astronomer had claimed.

In the second half of the 16th 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 dealt with planetary motion, trying to find laws that would explain it. He went from defending the Pythagorean laws of harmonic motion to putting them aside as they 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 its movements by 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.

The polyhedra abandoned, he went on to try various circular combinations, which also suited his religious beliefs. Faced with failure, he tried ovals. Finally he opted for ellipses, publishing his three laws that describe the motion of the planets.

Isaac Newton

Already at the end of the 17th century Isaac Newton discovered the law of gravitation. This was fundamental to explain the shapes of the orbits. With this, heliocentrism gained strength against other visions of the cosmos.

References

1. Astronomy. Nicolás Copernicus and the heliocentric theory. Obtained from astromia.com
2. EcuRed. Heliocentric theory. Obtained from ecured.cu
3. Barrado, David. When the Earth stopped being the center of the Universe. Obtained from elmundo.es
4. The Editors of Encyclopaedia Britannica. Heliocentric system. Retrieved from britannica.com
5. Beavers, Bethany. Heliocentric Model of the Solar System Facts. Retrieved from sciencing.com

6. Impey, Chris. Copernicus and the Heliocentric Model. Retrieved from teachastronomy.com
7. Astronomy Education at the University of Nebraska-Lincoln. Heliocentrism. Retrieved from astro.unl.edu
8. Rabin, Sheila. Nicolaus Copernicus. Retrieved from plato.stanford.edu