Description A multitude of balloons ascend at the Steamboat, Colorado balloon fest. More about hot air balloons.A hot air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries passengers and a source of heat, in most cases an open flame caused by burning liquid propane. The heated air inside the envelope makes it buoyant since it has a lower density than the colder air outside the envelope. As with all aircraft, hot air balloons cannot fly beyond the atmosphere. The envelope does not have to be sealed at the bottom, since the air inside the envelope there is at about the same pressure as the surrounding air. In modern sport balloons the envelope is generally made from nylon fabric and the inlet of the balloon (closest to the burner flame) is made from a fire resistant material such as Nomex. Modern balloons have been made in all kinds of shapes, such as rocket ships and the shapes of various commercial products, though the traditional shape is used for most non-commercial, and many commercial, applications. The hot air balloon is the first successful human-carrying flight technology. The first hot-air balloon flown in the Americas was launched from the Walnut Street Jail in Philadelphia on January 9, 1793 by the French aeronaut Jean Pierre Blanchard. Hot air balloons that can be propelled through the air rather than simply drifting with the wind are known as thermal airships.
William Castner, Boulder Member Since June 2019 Artist Statement Fine art photographer based in Boulder, Colorado. I exhibit in several regional galleries and hang in hospitals, hotels, corporate offices and private collections. I work extensively with art consultants and interior designers nationwide. My photography has been published in magazines, newspapers, textbooks and as posters, calendars and note cards.