The Centennial Light is an
incandescent light bulb
An incandescent light bulb, also known as an incandescent lamp or incandescent light globe, is an electric light that produces illumination by Joule heating a #Filament, filament until it incandescence, glows. The filament is enclosed in a ...
recognized as the oldest known operating light bulb. It was first illuminated in 1901, and has only been turned off a few brief times since. It is located at 4550 East Avenue,
Livermore, California
Livermore is a city in Alameda County, California. With a 2020 population of 87,955, Livermore is the most populous city in the Tri-Valley, giving its name to the Livermore Valley. It is located on the eastern edge of California's San Francisc ...
, and is open to public viewing.
Due to its longevity, the bulb has been noted by ''
The Guinness Book of World Records'', ''
Ripley's Believe It or Not!
''Ripley's Believe It or Not!'' is an American franchise founded by Robert Ripley, which deals with bizarre events and items so strange and unusual that readers might question the claims. Originally a newspaper panel, the ''Believe It or Not'' ...
'', and
General Electric
General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston.
Over the year ...
.
[.] The light has been the subject of many TV shows and news reports along with at least four books, and has its own website.
The handmade lightbulb was originally manufactured by the Shelby Electric Company of
Shelby, Ohio
Shelby is a city in Richland County, Ohio, United States. Located northwest of the city of Mansfield, Ohio, Mansfield, it is part of the Mansfield metropolitan area. The population was 9,282 as of the 2020 United States census, 2020 census.
His ...
, towards the end of the 1890s and donated to the
Livermore-Pleasanton Fire Department in 1901. It has been relocated several times since and remains in the care of the fire department to this day. The bulb's longevity has been attributed to the high quality of its manufacture,
it being seldom turned off,
and its low wattage.
Originally a 60-watt bulb, the light has for many years emitted dim light equivalent to a 4-watt bulb, about the strength of a nightlight.
History

The Centennial Light was originally a 60-
watt
The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...
bulb, but has since dimmed significantly and is now as bright as a 4-watt bulb.
The hand-blown, carbon-filament common light bulb was invented by
Adolphe Chaillet, a French engineer who filed a patent for this socket technology. It was manufactured in
Shelby, Ohio
Shelby is a city in Richland County, Ohio, United States. Located northwest of the city of Mansfield, Ohio, Mansfield, it is part of the Mansfield metropolitan area. The population was 9,282 as of the 2020 United States census, 2020 census.
His ...
, by the Shelby Electric Company in the late 1890s;
many just like it still exist and can be found functioning. According to Zylpha Bernal Beck, the bulb was donated to the Fire Department by her father, Dennis Bernal, in 1901.
Bernal owned the Livermore Power and Water Company and donated the bulb to the fire station when he sold the company. That story has been supported by firefighter volunteers of that era.
Evidence suggests that the bulb has hung in at least four locations. It was originally hung in 1901 in a hose cart house on L Street,
then moved to a garage in downtown Livermore used by the fire and police departments.
[.] The bulb was saved during the fire station's 1937 renovation, during which it was off for approximately one week.
Its unusual longevity was first noticed in 1972 by reporter Mike Dunstan. After weeks of interviewing people who had lived in Livermore all their lives, he wrote "Light Bulb May Be World's Oldest", published in the ''
Tri-Valley Herald''. Dunstan contacted the ''
Guinness Book of World Records
''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a British reference book published annually, listi ...
'', ''
Ripley's Believe It or Not
''Ripley's Believe It or Not!'' is an American franchise founded by Robert Ripley, which deals with bizarre events and items so strange and unusual that readers might question the claims. Originally a newspaper panel, the ''Believe It or Not'' ...
'', and
General Electric
General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston.
Over the year ...
, who all confirmed it as the longest-lasting bulb known in existence.
In 1976, the fire department moved to Fire Station #6 with the bulb; the bulb socket's cord was severed for fear that unscrewing the bulb could damage it. It was deprived of electricity for only 22 minutes during the transfer, which was made in a specially designed box and with full firetruck escort. An electrician was on hand to install the bulb into the new fire station's emergency generator. ''Ripley's Believe It Or Not'' stated that the short delay would not mar the bulb's continuous burning record. Since that move, the bulb has run continuously on an
uninterruptible power supply
An uninterruptible power supply (UPS) or uninterruptible power source is a type of continual power system that provides automated backup electric power to a electrical load, load when the input power source or mains electricity, mains power fai ...
; previously it had only been off the grid for short periods of time (e.g. a week in 1937 for a renovation and the odd power outage).
In 2001, the bulb's 100th birthday was celebrated with a community barbecue and live music.
On the evening of May 20, 2013, the general public witnessed, through a dedicated
webcam
A webcam is a video camera which is designed to record or stream to a computer or computer network. They are primarily used in Videotelephony, video telephony, live streaming and social media, and Closed-circuit television, security. Webcams can b ...
, that the bulb had apparently burned out. The next morning, an
electrician
An electrician is a tradesman, tradesperson specializing in electrical wiring of buildings, transmission lines, stationary machines, and related equipment. Electricians may be employed in the installation of new electrical components or the ...
was called in to confirm its status. It was determined that the bulb had not burned out when the dedicated power supply was bypassed, using an
extension cord
An extension cord (US), extension cable, power extender, drop cord, or extension lead (UK) is a length of flexible electrical power cable (flex) with a AC power plugs and sockets, plug on one end and one or more sockets on the other end (usuall ...
. The power supply was found to have been faulty. Approximately 9 hours and 45 minutes had passed before the light was reestablished.
The bulb is cared for by the Centennial Light Bulb Committee, a partnership of the Livermore-Pleasanton Fire Department, Livermore Heritage Guild, Lawrence Livermore National Laboratories, and Sandia National Laboratories. The Livermore-Pleasanton Fire Department plans to house and maintain the bulb for the rest of its life, regardless of length. When it does go out, they have no plans for it, although ''
Ripley's Believe it or Not!
''Ripley's Believe It or Not!'' is an American franchise founded by Robert Ripley, which deals with bizarre events and items so strange and unusual that readers might question the claims. Originally a newspaper panel, the ''Believe It or Not'' ...
'' has requested it for their collection of objects.
Reasons for longevity

Several reasons have been cited for the bulb's extensive lifespan. Its continuous operation has largely eliminated the stresses associated with turning a light bulb on and off, the act of which causes the temperature of the bulb to increase and decrease. The bulb was made by hand, using a carbon filament (of greater thickness and strength than the
tungsten
Tungsten (also called wolfram) is a chemical element; it has symbol W and atomic number 74. It is a metal found naturally on Earth almost exclusively in compounds with other elements. It was identified as a distinct element in 1781 and first ...
filaments used in most modern lightbulbs) along with brass and glass components of high quality. The low wattage (originally 60 watts, now approximately four) and high
nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
atmosphere inside the bulb have also contributed to its longevity.
Publicity
The bulb was officially listed in the ''Guinness Book of World Records'' as "the most durable light" in 1972, replacing the
Palace Theater Light in
Fort Worth, Texas
Fort Worth is a city in the U.S. state of Texas and the county seat of Tarrant County, Texas, Tarrant County, covering nearly into Denton County, Texas, Denton, Johnson County, Texas, Johnson, Parker County, Texas, Parker, and Wise County, Te ...
. The bulb was listed in the book for the next 16 editions. It was not listed during 1988–2006, without a reason being given, before returning in 2007. At least four books have been written about the bulb.
According to the fire chief, every few months a news outlet will publish a story on the bulb, generating visitors and general interest, then it will drop back into obscurity for a while. Dozens of magazines and newspapers have featured articles on the bulb.
The bulb has been visited and featured by many major
news channel
News broadcasting is the medium of broadcasting various news events and other information via television, radio, or the internet in the field of broadcast journalism. The content is usually either produced locally in a radio studio or telev ...
s
in the United States, including
NBC
The National Broadcasting Company (NBC) is an American commercial broadcast television and radio network serving as the flagship property of the NBC Entertainment division of NBCUniversal, a subsidiary of Comcast. It is one of NBCUniversal's ...
,
ABC,
Fox News
The Fox News Channel (FNC), commonly known as Fox News, is an American Multinational corporation, multinational Conservatism in the United States, conservative List of news television channels, news and political commentary Television stati ...
,
CBS,
WB,
CNN
Cable News Network (CNN) is a multinational news organization operating, most notably, a website and a TV channel headquartered in Atlanta. Founded in 1980 by American media proprietor Ted Turner and Reese Schonfeld as a 24-hour cable ne ...
and
NPR
National Public Radio (NPR) is an American public broadcasting organization headquartered in Washington, D.C., with its NPR West headquarters in Culver City, California. It serves as a national Radio syndication, syndicator to a network of more ...
.
The bulb has received letters acknowledging and celebrating its longevity from the city of
Shelby, Ohio
Shelby is a city in Richland County, Ohio, United States. Located northwest of the city of Mansfield, Ohio, Mansfield, it is part of the Mansfield metropolitan area. The population was 9,282 as of the 2020 United States census, 2020 census.
His ...
, the Alameda County Board of Supervisors, the
California State Assembly
The California State Assembly is the lower house of the California State Legislature (the upper house being the California State Senate). The Assembly convenes, along with the State Senate, at the California State Capitol in Sacramento, Califor ...
, the
California State Senate
The California State Senate is the upper house of the California State Legislature (the lower house being the California State Assembly). The state senate convenes, along with the state assembly, at the California State Capitol in Sacramento.
...
, Congresswoman
Ellen Tauscher
Ellen O'Kane Tauscher (November 15, 1951 – April 29, 2019) was an American businesswoman, diplomat, and Democratic Party politician who was the U.S. representative for California's 10th congressional district from 1997 to 2009. From 2009 to 20 ...
, Senator
Barbara Boxer
Barbara Sue Boxer (née Levy; born November 11, 1940) is a retired American politician, lobbyist, and former reporter who served in the United States Senate, representing California from 1993 to 2017. A member of the Democratic Party (United St ...
, and President
George W. Bush
George Walker Bush (born July 6, 1946) is an American politician and businessman who was the 43rd president of the United States from 2001 to 2009. A member of the Bush family and the Republican Party (United States), Republican Party, he i ...
. The bulb was featured on an
episode
An episode is a narrative unit within a larger dramatic work or documentary production, such as a serial (radio and television), series intended for radio, television or Streaming media, streaming consumption.
Etymology
The noun ''episode'' is ...
of ''
MythBusters
''MythBusters'' is a science entertainment television series created by Peter Rees (producer), Peter Rees and produced by Beyond International in Australia. The series premiered on the Discovery Channel on January 23, 2003. It was broadcast in ...
'' on December 13, 2006,
[.] in the
PBS
The Public Broadcasting Service (PBS) is an American public broadcaster and non-commercial, free-to-air television network based in Arlington, Virginia. PBS is a publicly funded nonprofit organization and the most prominent provider of educat ...
documentary ''Livermore'' and an episode of ''
California's Gold'' with Huell Howser, in an episode of ''
99% Invisible
''99% Invisible'' is a radio show and podcast produced and created by Roman Mars that focuses on design. It began as a collaborative project between San Francisco public radio station KALW and the American Institute of Architects in San Franc ...
,'' and mentioned in the web series ''
17776.''
See also
*
Eternal flame
*
Longest-lasting light bulbs
*
Phoebus cartel
References
External links
Official website for the bulb
{{Good article
Incandescent light bulbs
Individual lamps
Livermore, California
1901 establishments in California