This week we hung out with the Houston Museum of Natural Science’s vice president of astronomy Dr. Carolyn Sumners and talked about the Foucalt Pendulum here at the museum.

The occasion? January 8 is Earth’s Rotation Day, one of those wild not-a-real-holiday holidays that we only celebrate on the internet.

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During our Facebook Live Dr. Summers gave us the lowdown on the pendulum, which has been a landmark inside the museum for decades now. There is a lot more to it than just a swinging weight that knocks over wooden pegs.

And yes, someone has to put those pegs back up every day as Dr. Sumners explains in the video.

Named after 19th century French scientist Léon Foucault who created the first one ever, it is one of the best ways we can prove that the Earth is a sphere and that it rotates once on its axis every 24 hours. We know its working because the Earth is spinning.

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According to Dr. Sumners the best pendulum on Earth would be located at the North Pole. Next time we hang with Santa Claus we will ask him if he has one.

The pendulum here at HMNS, with a cable length more than 60 feet long, is a mesmerizing must-see for anyone visiting our museum.