It’s always a good idea to throw out fun facts in conversations with family and friends, or better yet, new acquaintances. These make you sound smart, interesting, and you can make a good impression.

These can include a variety of things like, “Did you know that the tallest building in the world is the Burj Khalifa?” or “Did you know that the largest animal in the world is the blue whale?” or “Did you know that the fastest man-made object is a manhole cover?” Yeah, we didn’t believe that either. Until it became apparent that it was true. The more you know!

More info: Robert Brownlee | Nuclear Weapon Archive

Back in the late 1950s, the US was conducting a lot of nuclear bomb tests under the name Operation Plumbbob

Image credits: Public Domain

A total of 29 tests were carried out in the Nevada Test Site from May to October of 1957. On August 27, 1957, around an hour before midnight, a test called Pascal-B (originally Galileo-B) took place. Like Pascal-A, it was a one-point criticality safety test of the same design. Except, it had a concrete plug similar to the collimator used in the Pascal A test, which was placed just above the device at the bottom of the shaft.

Image credits: iwishmynamewasmarsha

The collimator was so close to the explosion that it was, quite literally, vaporized. The extremely heated gas quickly expanded and blasted towards the top of the shaft where a steel plate was in place. Needless to say, the plate did not conceal the explosion and instead skyrocketed into the heavens at a speed of 56 km/s, which is 201,600 kilometers or 125,268 miles per hour.

Image credits: National Nuclear Security Administration

In perspective, this is approx. five times faster than the Earth’s escape velocity or roughly 775 times faster than a 2019 Ford Mustang GT 5.0. High-speed cameras filmed the steel manhole cover as it was flying sky-high, but scientists never found it afterward. It is very unlikely that the object managed to leave Earth as it would simply not be able to retain its speed given its lack of aerodynamics and other physical earthly forces. The dominant theory is that it was way beyond the reach of any search party to find.

Image credits: Atomic Heritage Foundation

So, the next time you need to spice up a conversation with a fun fact, go for the 125,000 miles per hour nuclear power propelled steel manhole cover.

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