Photographer's Note


Five hundred years ago Leonardo da Vinci expressed an abiding aspiration to achieve manned flight, in the manner of birds. In a photo, Leonardos Dream, that I posted on the great artist-scientist-engineers 555th birthday, a pair of Canadian Geese were seen in midair, and 10,000 meters above them the contrail of a commercial jet. That image was emblematic of heavier-than-air flight. Four hundred years after Leonardos prescient musings, the Wright brothers fulfilled his dream, constructing a manned kite powered by a gasoline-powered engine, and managed to stay aloft for 59 seconds and traveling 300 meters. This first ever heavier-than-air flight took place in Kitty Hawk, North Carolina on December 17, 1903. The dizzyingly swift progress of flight technology culminated just sixty-six years later (on July 20, 1969), when three NASA astronauts were launched from Florida on a multi-stage Apollo rocket, they reached the moon; one of them stayed in a lunar orbit, while two of them descended, walked on the moon; then all three returned safely to the earth.

Lighter-than-air flight, however, was achieved in France late in the 18th century. It started with experimentation made by the Montgolfier Brothers, Joseph Michel (1740-1810) and Jacques tienne (1745-1799). When air is heated, it expands, and in the process, its density falls below the density of cool air. Accordingly it rises. From conception to implementation, the hot air balloon came to fruition in the two years, 1782-1783. Two of the Montgolfiers experiments were especially memorable: on September 19, 1783 a balloon, carrying a number of farm animals (a sheep, a duck and a rooster) rose from the grounds of the Palace of Versailles, to an elevation of 1.6 miles. (This fact is most likely familiar to my good friend, Jean Charles Guegan (JCG) who lives in the area of Versailles, and has been posting compelling photos from his world.)

Then just two months later, on November 21, 1783, the first manned flight of a hot air balloon took place, when the Marquis d'Arlandes and Jean Piltre de Rozier, a physicist, flew over Paris, becoming the first test pilots as well as the first passengers of human flight. They achieved a height of 900 meters (3,000 ft) and traveled approximately 14 km (9 miles) during a 23-minute flight. Their balloon was constructed of linen, lined with paper, and coated with alum-potash, in order to reduce the risk of fire. The lift came from air heated by a pile of burning straw resting on a wire mesh. For the science-minded among TE members, a salutary effect of the hot-air balloon experiments was the discovery by an associate of the Montgolfiers, Jacques Charles. Charles Law, formulated in the early 19th century, shows that the pressure multiplied by the volume of a gas varies directly with the temperature, PV=nRT. In modern hot air balloons, air is heated with propane or natural gas that is carried in special tanks.

The present photo represents a view from the gondola of a hot air balloon of another balloon just taking flight. The vantage point from the higher elevation reveals a birds eve view of the balloon, attractive spiral patterns created by the colored patches comprising its surface. Meanwhile, the virtually monochromatic background seen below the balloon is the endless sand in the vicinity of Luxor, Egypt. Since none of the great temples of Luxor, or of nearby Karnak, are visible, it made more sense to write about hot air balloons than the history of the land below. That history came with a note accompanying my earlier post, the Feluccas on the Nile. I centered the balloon in the frame, since there was no other landmark to serve as a counterpoint. It would have appeared artificial to have the balloon 1/3 of the way from one side for no other reason than the "rule of thirds."

Hand held Nikon D-70, 18-70 mm lens.

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Additional Photos by Bulent Atalay (batalay) Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 6774 W: 470 N: 12149] (41261)
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