It is well known that Florence is a city with strong connections to the subjects of art and history, hosting some of the most world-renown works of art in its museums, and greeting thousands of visitors everyday hoping to absorb as much historical knowledge as they can in their short stay. The past breathes life into the city and all who venture here. However, there are some lesser known aspects of Florence that retain their own magic, specifically in the field of science.
The dome of Cattedrale di Santa Maria del Fiore itself is an amazing scientific accomplishment, but perhaps something even more marvelous housed in the dome, is the Gnomon. This device is basically a circular hole located in the top of the dome which, in the past, allowed scientists to observe the passage of the sun through night and day, marking the solar year.
With the technology we have today, the practical need for such instruments has ben eliminated, but the gnomon is still a major attraction. This year, during the summer solstice, you will be able to witness the phenomenon of the disk of sunlight from the hole falling on the floor of the cathedral to match up with its marble counterpart on the floor below. The opportunities to see this will be June 12, 20, and 25 between 12.30 and 13.30 in the afternoon. The light show takes place in the chapel of the cross, to the left of the main alter. Regular admission into the cathedral, as usual, is free.
The gnomon has been in use in the dome since 1475, when it was designed and installed by a Florentine mathematician by the name of Paolo Dal Pozzo Toscanelli. It was built 90 meters above the floor, with a small opening in the middle of a circular bronze plate, and is the biggest of its kind in the world. There are other, similar devices located in churches around Italy and France, but none as high up as Florence's. Its extreme height is the reason that the rays of light only reach the floor during a short period of time each year. When the sun falls through the hole, it moves across the meridian line on the floor of the church, marking the solstice when it matches with the specific marble circle.The device was used to its full potential for about 300 years after its installment, however due to scientific inconstancies such as the shift of the earth, or change of altitude of the Sun in the sky, the gnomon lost its accurate accredibility. Now it can be used to help determine the stability of the structure of the cathedral by taking the measurements every year and looking for any differences of the light matching up with the marble circle on the floor. This is an occurrence that can only be witnessed during these few days, and a truly magnificent historical and scientific accomplishment. The ingenuity of famous Florentine people keeps the past alive and inspires new inspiration in our own lives.
