How The World's Oldest Light Bulb Has Stayed Lit For Over 100 Years

To look at the Centennial Bulb, you might not think there was anything so special about it. There it dangles, from the ceiling of a fire station at 4550 East Avenue in California's Livermore. A bare bulb, no elaborate lampshade or anything. Humble as it may look, though, this light bulb is very famous indeed. It was fitted in a fire station in 1901, created by the Shelby Electric Company. Though it has changed position over its long life, it has remained functional. Guinness World Records deems it the world's longest burning light bulb, though it notes that the bulb hasn't technically been lit the entire time since its installment: It has been temporarily offline, such as when it was moved to a different building. Regardless of this, its long working life is confounding, and there is no singular, definitive reason why a product of a time long before the advent of smart bulbs and smart switches has endured as long as it has. 

It's become quite the tourist attraction, with its 'official' website offering a guest book for visitors to sign as well as the Bulbcam live feed that interested parties can use to check in on it. It appears that the materials it was made from contribute to its resilience, with creator Adolphe Chaillet using glass that was blown by hand and a very dense filament, which may have both helped its glass shell to remain intact and its light to continue to illuminate. Another primary contributing factor is that its light now burns at a meager four watts, which means that it produces very little light but, as a result, burns very little power. As such, it has lasted much longer than the lifespan of some smart light bulbs.

The Centennial Light, Centennial Bulb, or whatever you'd like to call it, then, has burned for approximately 124 years as of the time of writing. This adds up to around 1,086,240 hours. While we know that it hasn't been constantly illuminated for all of that time, there was no question among its many fans that the big one millionth hour of operation had to be celebrated. The big party took place in June 2015, with The Independent reporting that the fire station showcased some items from its history, sold some merchandise, and hosted a barbecue. All in all, it was a perfect time to celebrate local history and continue to foster community spirit and pride.

The bulb has since gone on to burn for around another decade, and who's to say how much longer it might last? In 2011, The Mercury News quoted the U.S. Naval Academy's Debora Katz as likening it to "sort of an animal with a low metabolism," in that "It's giving us less energy ... so it can keep on going longer." It might have 1,250,000 hours in it. Perhaps 1,500,000. All that can be said for certain is that the plucky bulb will only become more impressive as more time goes by. Consider, for instance, the fact that Philips boasts its hue smart bulbs "can last up to 25 years." There are factors that work in the Centennial Bulb's favor, but that takes nothing away from this impressive antique.