Time is the only resource we can never reclaim—and yet, through one astonishing feat of human engineering, we may have ever so slightly extended it. According to a groundbreaking study led by Dr. Benjamin Fong Chao of NASA’s Goddard Space Flight Center, the Three Gorges Dam in China has measurably altered the Earth’s rotation, making each day longer by an estimated 0.06 microseconds.
That might not sound like much—just 60 millionths of a second—but over long periods, this tiny shift accumulates. Over the 13.8 billion years of the universe’s age, it would amount to more than three extra days. This finding isn’t just theoretical—it’s backed by precise satellite measurements, and we’ve included a fascinating video in this post that visually breaks it all down.
The Three Gorges Dam, straddling the Yangtze River, is the world’s largest hydroelectric facility. Completed in 2012, it holds nearly 40 cubic kilometers of water and produces over 100 terawatt-hours of electricity annually. Its benefits for flood control, clean energy, and navigation are massive—but so, too, are its geophysical consequences.
By moving an enormous volume of water from low elevations to a high-altitude reservoir, the dam has redistributed mass across the Earth’s surface. This shifts the planet’s moment of inertia, similar to a figure skater extending their arms to slow their spin. The result: Earth now rotates a tiny fraction more slowly.
Dr. Chao’s team used data from NASA’s GRACE satellite and other geodetic tools to observe these subtle but real changes. Alongside the extended solar day, they also detected a 2-centimeter shift in Earth’s axis—tilting slightly toward the dam’s latitude. These changes are incredibly small, but completely within the limits of modern scientific detection.
The video linked above explains this phenomenon in accessible, visual detail—don’t miss it if you want to truly grasp how global infrastructure can ripple through the very fabric of planetary physics.
But it’s not just about numbers. This story touches on something deeper: the power and responsibility of humanity as a geological force. The Three Gorges Dam has displaced over 1.3 million people, flooded ancient cultural sites, and altered ecosystems. Now we know it has also left a permanent mark on the mechanics of our planet.
So the next time you feel time slipping away, remember: somewhere in central China, a massive reservoir is gently resisting the spin of the Earth—giving us all a fractional gift of time, made possible by the awe-inspiring, and humbling, scale of human achievement.
👉 Check the video below to see the full explanation.