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Bologna, San Petronio: Meridian of Giandomenico Cassini

Synchronizing Science and Religion? Why We Find Solar Observatories and Astronomical Features in Churches

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It is often assumed that science and faith are always at loggerheads with each other. This, however, is a common misconception, as there are numerous instances demonstrating the co-existence and co-operation between science and religion. One of these, for example, is the relationship between the Roman Catholic Church and astronomy, in particular, the former’s installation of astronomical features in churches, as well as their use of these sacred spaces as solar observatories.

Dome of Basilica Santa Maria degli Angeli e dei Martiri, Rome, Italy

Dome of Basilica Santa Maria degli Angeli e dei Martiri, Rome, Italy ( Public Domain )

Easter Calculations

For Catholics across the ages, the most important day of the year was Easter. Unlike Christmas, which is customarily celebrated on the 25 th of December, Easter is a moveable feast, which means that it would be celebrated on different dates each year. This was due to the fact that the correct prediction of this date depended (and still depends) on certain incredibly technical astronomical constants, including the length of a lunar month, i.e. 29.53059 days, and the length of a solar year, i.e. 365.2422 days. Traditionally, Easter is celebrated on the Sunday after the first full moon of spring. By the 12 th century, however, the normal ways used to predict the date of Easter had gone wrong, and the Catholic Church had to find other means of doing so. It may be added here that whilst the Gregorian calendrical reform of 1582 was instituted to address the question of the date of Easter, this problem still persisted.

It was imperative that Church authorities set the date of Easter years in advance, as this served to strengthen the Catholic Church’s power, and to ensure its unity. Therefore, astronomers were hired to work out the date of Easter. By pondering over old manuscripts and inventing devices that allowed them to observe the heavenly bodies, these astronomers not only successfully predicted the date of Easter years beforehand, but were also able to advance their science to greater heights. One of the evidences of this can be observed in churches, perhaps the last place that some would expect to find the presence of science. The most widely used international calendar, the Gregorian calendar was introduced by Pope Gregory XIII, as a more accurate tool to set the date of Easter than its predecessor, the Julian calendar.

Detail of by Pope Gregory XIII’s tomb by Camillo Rusconi (completed 1723); Antonio Lilio is genuflecting before the pope, presenting his printed calendar.

Detail of by Pope Gregory XIII ’s tomb by Camillo Rusconi (completed 1723); Antonio Lilio is genuflecting before the pope, presenting his printed calendar. ( CC BY-SA 3.0 )

Meridians

In various parts of Europe, many churches and cathedrals have had astronomical features incorporated into them. One of the most visible of these is the meridian line. This was a device that enabled the astronomers of the time to measure precisely the progress of the Sun throughout the year. In other words, such cathedrals and churches in which meridian lines are found are in effect solar observatories. Some examples of places where meridian lines can be found include the Basilica of San Petronio in Bologna (Italy), the Basilica of Santa Maria degli Angeli e dei Martiri in Rome (Italy), the cloister of Durham Cathedral in Durham (England), and the Church of Saint-Sulpice in Paris (France).

The meridian line in the Basilica of Santa Maria degli Angeli e dei Martiri, Rome.

The meridian line in the Basilica of Santa Maria degli Angeli e dei Martiri, Rome. ( CC BY-SA 3.0 )

During that time, cathedrals and churches were the obvious choices for the construction of meridian lines for a couple of reasons. First of all, for a meridian line to function properly, a large, flat surface was needed, so that the meridian line could be drawn. Next, an open volume of unobstructed space was required, so that a precise beam of sunlight could shine through. Thirdly, a hole needed to be made in a ceiling high enough so that the beam of sunlight may be tracked for long distances, from one solstice to the next, and back again. Thus, cathedrals and churches were the ideal structures that the Church authorities had at their disposal for the construction of these meridian lines.

Meridian solar line of the Basilica Santa Maria degli Angeli e dei Martiri in Rome built by Francesco Bianchini (1702)

Meridian solar line of the Basilica Santa Maria degli Angeli e dei Martiri in Rome built by Francesco Bianchini (1702) ( CC BY-SA 3.0 )

Perhaps one of the unintended effects of having these incredibly precise meridian lines was the increasing realisation that the Earth was not stationary, but revolved around the Sun. In other words, the geocentric model held by the Catholic Church was incorrect. Although the Church vehemently rejected the newly-proposed heliocentric model, it eventually came to accept it. This does not mean, however, that the Church washed its hands of astronomy altogether. When the meridian lines were being built, astronomers had already been in the service of the Church for centuries. This patronage by the Catholic Church continues even today, with the Vatican Observatory serving as evidence of the continued interaction and co-operation between the faith and science.

The Vatican Advanced Technology Telescope (VATT), the main telescope of the Vatican Observatory.

The Vatican Advanced Technology Telescope (VATT), the main telescope of the Vatican Observatory. ( CC BY-SA 3.0 )

Top image: Bologna, San Petronio: Meridian of Giandomenico Cassini ( CC BY-SA 3.0 )

By Wu Mingren 

References

A Road Retraveled, 2013. Roman Church or Solar Observatory?. [Online]
Available at: http://www.aroadretraveled.com/roman-church-solar-observatory/

Broad, W. J., 1999. How the Church Aided 'Heretical' Astronomy. [Online]
Available at: http://www.nytimes.com/learning/students/pop/101999sci-astronomy-cathedrals.html

Burnett, D. G., 1999. What Time Is It in the Transept?. [Online]
Available at: http://www.nytimes.com/books/99/10/24/reviews/991024.24burnett.html

Manaugh, G., 2016. Why Catholics Built Secret Astronomical Features Into Churches to Help Save Souls. [Online]
Available at: https://www.atlasobscura.com/articles/catholics-built-secret-astronomical-features-into-churches-to-help-save-souls

O'Brien, T., 2014. In Praise of Meridian Lines. [Online]
Available at: http://proftimobrien.com/2014/12/in-praise-of-meridian-lines/

UNESCO, 2017. Theme: Medieval astronomy in Europe. [Online]
Available at: https://www3.astronomicalheritage.net/index.php/show-theme?idtheme=16

Comments

Hi All,

This is an excellent article I hadn't notice the Church studying Astronomy especially since Galileo angered the Mother Church at the time Roman Catholic. I do think that the churches interest about Astronomy is because of Their Bible an other Sacred Text that they later tossed aside.

Not too mention the Soul basis of Christendom is to be Watchful of The Second Coming Christ that's basically what Christians in Theory are to Watch for is The Second Coming.

Hi All,

This is an excellent article I hadn't notice the Church studying Astronomy especially since Galileo angered the Mother Church at the time Roman Catholic. I do think that the churches interest about Astronomy is because of Their Bible an other Sacred Text that they later tossed aside.

Not too mention the Soul basis of Christendom is to be Watchful of The Second Coming Christ that's basically what Christians in Theory are to Watch for is The Second Coming.

Hi All,

This is certainly an compelling article on going on's of the Church and seeking Astronomy Scholars enlighten them most intriguing. Although, I do have a hunch that The Early Church was using Biblical Reference to conduct those same Astronomical observations Sacred Text they would much later throw out.

In the case of The Julian Calendar & The Gregorian Calendar I believe both were created due to the growing amount of Anti-Semitism taking place against The Jewish population's. My reasoning because a good portion of Astronomical observances were originally based on The Hebrew Calendar.

About a year or 2 ago Easter Holiday as mentioned in The Article was moved too the First Week of April.

At the same time Easter was placed first week of April a News Report about The Greek Orthodox Church was shared unlike, everywhere else, This Church seems to follow the Hebrew Calendar for when The Passover Holiday is too take place and then The Greek Church would observe Easter after the Holiday.

I remember thinking how awesome it was The Greek Orthodox Church was for doing that with regards to when they celebrated Easter.

Based on that huge Astronomy Observatory in the picture accompanying this article this might be a wild guess but, I also feel that the Catholic Church is Watching for The Second Coming of Christ since that's the main reason why a majority of us are identified as Christian's.

All in all this was an excellent article for me to read about, so until next time, Everyone, Goodbye!

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