Can you imagine a dam so huge that it can slow down the daily movement of the Earth? Well, there is one. The massive construction of China- Three Gorges dam is slowing the Earth’s rotation slightly by a fraction of 0.06 microseconds per day. This has been revealed in the latest research by NASA. It has also unveiled the shocking connection between human engineering and the planetary dynamics, with the largest hydroelectricity project of the world slowing down the Earth.

This kind of phenomenon occurs due to the dam’s enormous reservoir, which redistributes the mass of the Earth and alters the moment of inertia in a subdued manner. The finding sheds light to the profound and unanticipated consequences of the large-scale human activities on nature.

The reservoir of the Three Gorges Dam holds as much as 40 billion cubic meters of water, immense enough to cause a significant redistribution of mass on Earth. It’s water accumulation changes the distribution of weight across surface of the planet altering Earth’s rotational dynamics. As explained by a NASA scientist Benjamin Fong Chao, “Redistribution of mass within the Earth’s system produces an effect on Earth’s rotation. While the delay of 0.06 microseconds per day may seem negligible, it is a measurable consequence of this redistribution.”

The effect is based on the principle that shifting the mass closer towards the poles speeds the Earth’s rotation, while it is slowed down as the mass moves closer to the equator.

The Three Gorges Dam is a visible testament of human innovation and growth. It stands tall at a height of 185 m above the Yangtze river spread across an area of 2 kilometers. The dam alone generates an enormous 22,500 megawatts of electricity, which is more than the overall electricity generation of some countries of the world. In 2020, the Three Gorges Dam produced 112 terawatt- hours of electricity which was a new record. It has also stamped on its status of being the top contributor of renewable energy in the world. But, as we can see that the impact is much more than that. It is far beyond than energy consumption alone, it is influencing the physical attributes of the planet, per say the 24-hour rotation cycle.

Earth’s ability to spin depends on the distribution of its mass relative to its axis of rotation. This measures Earth’s moment of inertia. The balance of Earth’s mass is a delicate phenomenon, which when shifted towards the equator can slow down the rotation or accelerate it if moved towards the poles. The small significant changes can change the landscape of the Earth. Thus, it is important that the anthropogenic activities do not harm the already established natural systems.

The Three Gorges Dam is just a mere example. Human activities like the large-scale infrastructural projects of constructing dams and groundwater extractions can influence the sea levels, tilt the Earth’s axis and redistribute the mass. It is the extent to which the human induced phenomena collide to the natural phenomena changing the dynamics of the Earth at large.