The Coso Artifact: A 500,000-year-old spark plug?

Coso artifacts
Coso Artifacts © BigThink

OOPArt (Out Of Place Artifact), is a term used to refer to dozens of prehistoric objects found in different places around the world that seem to show a certain level of technological advance incongruous with the time they were made. OOPArts often frustrate mainstream scientists, fascinate intrepid researchers open to alternative theories, and spark heated debate.

The Coso Artifact: A 500,000-year-old spark plug? 2
The Baghdad Battery, otherwise known as the Parthian Battery, is a 2,200-year-old clay jar found near Baghdad, Iraq, which has been described as the oldest known electric battery in existence. It’s one of the most famous OOPArts in the world. ☰Read

For many years, quite a few OOPArts have been found around the planet. But without a doubt, one of them that has given archaeologists the most headaches and has fascinated alternative experts is the object of Coso; a feasible 500,000-year-old spark plug.

Coso Artifact: The strange discovery

Coso artifacts
The artifact of Coso © Youtube screenshot

On February 13, 1961, Mike Mikesell, Wallace Lanbe and Virginia Maxey set out to search geodes for gems and semi-precious stones for their Olancha, California gift shop. This was not an unusual activity since they frequently collected mineral samples that, once analyzed, were used to display and sell in their trade. But that day, Mike Mikesell found a common geode for the area, but “in a way it seemed to be something different.”

Apparently, it was not a true geode because its outer crust was made of a kind of hardened clay in which fossil shells could be seen, nothing strange if we consider that the place of the find was covered by waters in ancient times.

The next day, Mike broke the diamond blade on his saw while trying to cut the strange-looking geode in his workshop. Thanks to this he discovered something shocking: inside the geode, he found something similar to an artifact ― a circular object made of something similar to porcelain, with a shiny metal rod about 2 mm thick in its centre. In fact, no one would call it anything but a spark plug. But how old could it be if it was embedded in the geode?

When the object was examined by Paul Willis, then editor-in-chief of INFO magazine pointed out its resemblance to a modern spark plug such as those used in automobiles, which unfailingly marked later appreciations of the object. Willis himself made a schematic drawing of the interior of the “geode.”

Coso artifacts
These grainy images, thought to have been originally published in a magazine dedicated to the paranormal, are all that remain of the “Coso artifact.” The object itself hasn’t been seen in decades. Clockwise from top: The “geode” in which the artifact was found, an x-ray of the interior, and a side view after the “geode” had been cut in half © INFO Journal

Certainly examining the object as a whole consisting of the metal rod, a piece of copper and a piece of ceramic, it gives all the sensation of being the remains of some electrical device. In fact, years later Paul and Ronald Willis, by way of experiment, sawed a modern spark plug in two and found that all the components greatly resembled the strange object of Coso.

The ‘Coso Artifact’ could be around 500,000 years old?

Coso Artifact
The Coso Artifact © Wikimedia Commons

Virginia Maxey said at the time that a geologist had examined the fossils (rocky wrapper) that covered the artifact and that they dated back at least 500,000 years. So you have to ask yourself, what is a spark plug doing in a geological layer 500,000 years ago, hundreds of thousands of years before the supposed establishment of developed civilizations took place?

Was the ‘Coso Artifact’ coated with a fast-setting material, rather than a geode?

However, this ‘500,000 years theory’ has been disputed, especially by Pierre Stromberg and Paul V. Heinrich, who attempted to prove that the spark plug was manufactured in 1920 and coated with a fast-setting material, rather than a geode.

The only people who conducted a physical examination of the artifact were the three who found it and Ron Calais, who was convinced that the official figures surrounding human history were incorrect. For years this artifact was on display in the home of Wallace Lane, another of the original three discoverers, who – according to Heinrich and Stromberg – was reluctant to let others examine it. To this day its current location is unknown.

In addition, the name of the geologist who claimed that the piece was 500,000 years old was never known, which also caused many to question the veracity of the supposed study carried out. However, it is also true that Heinrich and Stromberg claimed that ” there is no solid evidence to show that the original discoverers wanted to deceive someone.”

Without being able to investigate the artifact itself, they also exposed the fact that, perhaps, the material that covers it was not a geode, based on the first description of its original discoverers, who stated that it was covered with a kind of hard clay or rock.

Heinrich and Stromberg then approached the president of the SPCOA (Spark Plug Collectors of America), a group of spark plug collectors from the United States, with a series of X-ray images of the object that were published by Calais at the time. From this association, it was concluded that it was a Champion spark plug from 1920.

Coso artifacts
An example of a 1920s Champion spark plug © Wikimedia Commons

Those who affirmed that the spark plug was ancient or prehistoric were positioned against this conclusion, assuring that in its upper part it presented a strange propeller or spring that does not exist in the modern spark plugs.

Finally, Heinrich and Stromberg replied that, in 1920, the ‘Champion’ plug was manufactured with a “brass shell” that would correspond to this spring, although this part was not included in later designs.

The ‘Coso Artifact’ was revealed again in 2018

Accoding to some sources, on April 12, 2018, Pierre Stromberg was contacted by the family of one of the co-discoverers of the artifact. They Offered him an opportunity to physically inspect the artifact. Stromberg accepted and travelled to the rendezvous point and met with the family, who then revealed the artifact.

Stromberg also arranged for the artifact to be inspected by geologist B. Charlotte Schreiber from the University of Washington Earth and Space Science department.

The inspections confirmed the previous conclusion that the artifact was a 1920s-era Champion spark plug. No shells or shell impressions were detected on the surface of the artifact. Though the research data hasn’t been published anywhere in detail, and no one knows much about it.


One thing is certain, the ‘Coso Artifact’ is not like the Antikythera Machine ― which has been deeply analyzed and studied in detail and can currently be seen in the National Archaeological Museum of Athens. The Coso Object has not been examined by any accredited person and its current whereabouts are unknown. If it weren’t for the INFO magazine article, the X-rays and the photographs taken, even today it might even be thought to be nothing more than a myth.

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