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Spin Into the New Year with Earth's Rotation Day

January 7, 2022

January 8th, the last remnant of 2021, the day when the Earth truly completes its orbit around the sun. We celebrate this accomplishment each year as "Earth's Rotation Day."

Traditional calendars and timekeeping are the slightest bit off in regards to Earth’s actual position to the sun; one rotation is a little more than 24 hours, adding up to make a trip around the sun more than 365 days. We have the countermeasure of leap years every four years, as well as skipping leap year every century in order to combat getting too off course in our timekeeping, but until those adjustments come, we have Earth’s Rotation Day to keep us on track.

According to, the need for the day was noted in the year 1851. “French physicist Léon Foucault demonstrated how the earth rotates by suspending a lead-filled brass ball from the top of the Panthéon in Paris. This device, now known as the Foucault Pendulum, showed that the plane of the swing of the pendulum would rotate relative to the Earth’s own rotation.”

Because of the pendulum’s movement in relation to the Earth’s plane, it will appear to change directions every few hours.

“Although it seems like the floor is the stable part of the contraption and the change is the way the pendulum is swinging, in reality, the change is the fact that the earth beneath the feet is slowly rotating while the pendulum stays the same.”

Though the invention of the Foucault pendulum marked the need for Earth’s Rotation Day, when and how the holiday was founded is unknown. It may have come within Foucault’s lifetime, but we cannot know for sure. If nothing else, we can still honor the physicist’s memory when we celebrate. If you’re looking for a specific way to celebrate Earth’s true completed orbit around the sun, you can always visit the local space museum to learn about the science of our stars and our relation to them. recommends the Houston Museum of Natural Science, the Science Center of Iowa, and the California Academy of Sciences, all which have a Foucault Pendulum as part of their exhibits.

Don’t have the time/money/energy to make the trip? Never fear! You can look forward to the ALPHA Observatory coming to Capitol Tech in the near future. The observatory will be built to monitor and gather data on Near-Earth Objects (or NEOs), allowing students to get a hands-on experience of observing the realm beyond our atmosphere and gleaning knowledge from what they find. Earth’s Rotation Day is a time to honor our space in the solar system, to recognize our place in the stars and marvel at our travel amongst them. Take a look at the sky this Earth’s Rotation Day and celebrate in your own way our trip around the sun.

Capitol Tech offers many opportunities in engineering and engineering technologies, where you can pursue an astronautical career focused on the discovery of space and how our planet plays a part in relation to the stars. To learn more about these programs, visit and peruse the various courses and degrees offered. Many courses are available both on campus and online. For more information, contact