Contrails and the Pisa Tower
I'm sitting in Gatwick airport, looking out over a very gray and wet airport. A real change in the weather from the north, from which I flew down this morning. I was in Aviemore last night, and when I left the hotel at the ungodly hour of 5:20 there was a light dusting of snow and a deep frost.
We sat on the ground for about an hour as the plane was de-iced, by a couple of Highland Airways lads in what looked like a transit van with a cherry picker on the roof. Careful, meticulous but slow.
I'm on my way to Pisa, to speak at an italian local government conference on regional development. I was there a couple of years ago - on a similar engagement - and took the chance to snap the famous tower, framed by jet contrails.
I never had time to climb it, but the tilt is fascinating, as is the engineering that made it safe.
Here is what Wikipedia has to say:-
"On February 27, 1964, the government of Italy requested aid in preventing the tower from toppling. It was however considered important to retain the current tilt, due to the vital role that this element played in promoting the tourism industry of Pisa.[2] A multinational task force of engineers, mathematicians and historians was assigned and met on the Azores islands to discuss stabilization methods. After over two decades of work on the subject, the tower was closed to the public in January 1990. While the tower was closed, the bells were removed to relieve some weight and cables were cinched around the third level and anchored several hundred meters away. Apartments and houses in the path of the tower were vacated for safety. After a decade of corrective reconstruction and stabilization efforts, the tower was reopened to the public on December 15, 2001. Many methods were proposed to stabilize the tower, including the addition of 800 metric tons of lead counterweights to the raised end of the base. The final solution to correcting the lean was to remove 38 m3 of soil from underneath the raised end. The tower has been declared stable for at least another 300 years."
