In Göttingen, Germany, there’s a four-tonne steel ball that can be raised up a 14-metre tower — and then dropped in less than two seconds, crashing back to earth. It makes tiny, artificial earthquakes.
Tom Scott visits Wiechert’sche Erdbebenwarte Göttingen‘s Mintrop-Kugel, a 4-ton steel ball named for German mine surveyor and geophysicist Ludger Mintrop, the first person to artificially produce earthquakes for science. The Wiechert earthquake station was built in 1902 under the direction of German physicist and geophysicist Emil Wiechert and is now home to the world’s oldest functional seismograph, an earthquake detection and recording instrument. From Scott’s video notes:
Three things I had to cut out of this video, because they didn’t quite fit into the story or because I couldn’t film them:
The reason the steel ball survived two world wars is because the university’s records listed it by use as a “rock-ball”, not by composition as a “steel ball” – so no-one melted it down for weaponry.
The observatory team refill that pit every year to make the ground flat, and the ball just digs a hole again. The rock’s just being compressed underneath. They joke that, somewhere in Australia, there’s a slowly growing hill…
And finally, the ground steams for a little while after the ball hits: it gets rather warm…
Read more about the station in this pdf in English.
Related reading: The Richter magnitude scale, and Zhang Heng’s dragon jar seismoscope, circa 132 AD.
Next: The Hammer-Feather Drop in the world’s biggest vacuum chamber, Surprising Applications of the Magnus Effect, and The Stacked Ball Drop (and Supernovas).