for National Geographic News
This year the Olympic torch is undergoing unprecedented abuse, from protesters jostling over it to howling winds atop Mount Everest to potential relay cancellations.
But the 2008 torch can take the heat.
Decades of innovation have made the torch the height of combustion technology—all in service to the ultimate flame imperative: The fire lighted at ancient Olympia in Greece on March 24 must be the same flame that lights the Olympic cauldron in Beijing on August 8.
According to Chinese press and the Beijing Olympics Web site, this year's torch boasts a flame that can withstand winds of up to 40 miles an hour (65 kilometers an hour), nearly 2 inches (5 centimeters) of rain an hour, and temperatures of minus 40 degrees Fahrenheit (-40 degrees Celsius).
The flame is fueled entirely by propane, which marks a departure from its predecessors.
The 2000 Sydney Olympics' torch burned a propane-butane mix. Athens's torch was run on propylene and butane, which produced a bit more soot but increased the flame's brightness—important for those daytime photo ops.
The state-owned China Aerospace Science and Industry Corporation designed the new torch's burning system—and it is, in a sense, rocket science.
Comparing modern Olympic torch technology and rocket design, engineer Richard Kelso said: "Both areas are very complex. And they require knowledge of combustion, fluid mechanics, thermodynamics, aerodynamics, materials science, and also manufacturing."
Kelso, of the University of Adelaide in Australia, was chief design coordinator of the 2000 Sydney Olympic torch's fuel-and-combustion system as well as a senior design engineer for the 2004 Athens torch.
"If [the 2008 torch's fuel] truly is propane then I would expect that the flame wouldn't be quite as bright as Athens and Sydney," Kelso said.
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