"Centennial Bulb" still burning after 107 years

Hanging about 18 feet high in the engine bay of a Livermore, California firehouse, a humble, low-watt light bulb has been burning almost continuously since 1901. Take that, halogen!

The Los Angeles Times (via Boing Boing) recently ran a story on the remarkably resilient Centennial Bulb—a four-watt, curlicue carbon-filament lightbulb that, give or take a few brief interludes, has been burning for 24 hours a day, seven days a week for more than a century.

The bulb has become something of a lucky charm for Livermore firefighters, who (according to the LA Times story) won't even dust off the bulb for fear of damaging it.

Indeed, when the department moved to a new fire station in 1976, firefighters decided to cut the power cord rather than unscrew the fragile bulb from its socket. A motorcade of fire trucks then accompanied the Centennial Bulb (which, according to Wikipedia, was only off for about 10 minutes during the short journey) to its new home, where it's been burning continuously ever since.

What's the secret to the Centennial Bulb's longevity? As the LA Times story notes, there are many theories. One former firefighter thinks it's because the bulb, made by the long-defunct Shelby Electric Co., shines in a cool-burning vacuum thanks to a perfect seal. Others chalk it up to the fact that the bulb has almost never been turned off.

In any case, the Centennial Bulb has been drawing curiosity-seekers and news stories (including, of course, this one) since 1972, and the bulb even has its own Web site—which, unfortunately, appears to be down for now (probably due to a burst of traffic).

Check out the LA Times Web site for the full story, including many more details on the bulb's storied history.

So, any theories on why the Centennial Bulb has been burning for so long? 

Related:
At 107, Livermore centennial lightbulb is still a real live wire [Los Angeles Times]