Friday, March 3, 2017

Beware of Falling Objects

What happens when you place a large metallic sphere on top of a tall building? 

The cathedral in Florence, the tallest structure in Florence, is topped by a large orb made of bronze.  It was designed by sculptor and painter Andrea del Verocchio, probably with the help of his students, including a young Leonardo da Vinci. 

Florence's cathedral, the Duomo, with a distant view of the orb on top of the cathedral's dome

The orb on top of the cathedral's dome
The orb was completed and first lifted to the top of the cathedral's dome in 1471.  Florentines celebrated the crowning of their 175 year old cathedral with singing, trumpets and cannons.  Surprisingly, the event was captured in a "photograph".  In a 1471 work by Florentine artist Biagio d'Antonio, the cathedral with scaffolding for lifting the orb can be seen in the background of a painting of the three archangels. 


Lifting the orb 375 feet was no small task.  The orb measures about 8 feet in diameter and weighs about 2 tons.  Fortunately, the Florentine builder of the cathedral's dome, Filippo Brunelleschi, had already perfected a machine for lifting very heavy objects.  So, up the ball went and there it stayed for more than a century.

Filippo Brunelleschi's lifting machine, as sketched by his student Leonardo da Vinci
Over time, lightning struck the orb, again and again.  After all, the ball was metallic, it was topped with a metallic cross acting as a lightning rod, and it was higher than any other object in Florence.  Repeated lightning strikes apparently weakened the structure supporting the ball in place.

In 1601, lightning stuck the ball again.  The bolt was so fierce that the ball detached from its perch atop the cathedral and rolled down the dome, falling 375 feet to the street below.  Fortunately, no one was standing on the exact spot where the 8-foot wide, 2 ton org landed. 


Despite any bad omen the falling orb represented, the Florentines put a new, larger orb on top of the cathedral two years later.  There, the new orb has remained for more than four centuries. 

The exact spot where the first orb landed is marked.  A circular piece of marble can be found in the street next to the cathedral.  We recently located the spot (pictured below).

Photo of a devil-may-care person standing on the spot where the 2 ton orb landed.  Not to worry, there was no thunderstorm when the photo was taken.

This photo gives you an idea of the ball's size.  (The ball in the photo is actually a slightly larger replacement ball that was refurbished a few years ago.)
So, what happens when you place a large metallic sphere on top of a tall building?  Lightning strikes it again and again, until one day it finally falls.

A sculpture of the dome's builder, Filippo Brunelleschi.  The sculpture is located next to the cathedral with Brunelleschi's gaze toward the dome.  Perhaps he is thinking, "Boy, I hope nothing else falls off the dome." 


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