A Curious Experiment
In 1957, during Operation Plumbbob, the U.S. conducted nuclear tests at the Nevada Test Site. One experiment, Pascal-B, involved detonating a nuclear bomb inside a 500-foot-deep shaft sealed with a heavy steel manhole cover.
The Incredible Launch
When the bomb detonated, the immense pressure created by the explosion launched the manhole cover skyward at an estimated speed of 125,000 miles per hour. This speed far exceeded Earth’s escape velocity, making it the fastest human-made object at the time.
Gone Without a Trace
The manhole cover was never found. Some theorize it vaporized due to extreme heat, while others speculate it might still be traveling through space. Its astonishing velocity captured imaginations and inspired debates among scientists.
A Record Untouched
Although never officially verified as a space-bound object, the Plumbbob manhole cover remains a fascinating footnote in the history of nuclear testing, demonstrating the incredible power of controlled explosions and human ingenuity.
In 1957, during Operation Plumbbob, a nuclear test unexpectedly launched a steel manhole cover at an estimated 125,000 miles per hour. This event at the Nevada Test Site made the cover potentially the fastest human-made object ever recorded.🧵👇 pic.twitter.com/lJYwwLqCkU
— Detective Tiger's Stories (@TigerDetective) January 20, 2025