Imagine you have an actual nuclear bomb sitting around in your office to play with. What is the most fun thing to do with it? If right now you are thinking of showing visitors how close you can get it to detonation without blowing yourself up, I salute your gallantry.
Of course, nuclear technicians in the 1940's already had that kind of steel balls (apparently along with lack of common sense or a will to live). You can probably imagine where this story goes...
Here is a question for you: What was the fastest ever man-made object?
You'd probably guess it's one of the Voyager probes - specifically Voyager-1 at currently almost 40,000 mph. And you'd be most certainly and hilariously wrong.
To zero in on the correct answer, you have to learn not to underestimate the curiosity (and nerdiness) of a bunch of nuclear scientists, having really, really big "toys" to play with.