IMAGE VIA PUBLIC DOMAIN

BY MADISON DAPCEVICH  | 26 MAY 2021 

FACT CHECK

China’s Three Gorges Dam — so named for the three chasms it encompasses — makes up the world’s largest hydroelectric dam. And the reservoir connected to the dam is capable of holding such a high volume of water that it is rumored to slow and change the rotation of the Earth.

The rumor has been in circulation for more than a decade. Plans for the Three Gorges Dam were finalized in 2021, which explained why the claim once again made the rounds this May.

Snopes contacted NASA, which confirmed that the claim had originated in a Jet Propulsion Lab report published in June 2005.

THE RESEARCH

Scientists compared the effects of the dam to the 2004 Indonesian earthquake, which prompted a tsunami that killed nearly 230,000 people. Shifts in mass like those resulting from earthquakes or reservoirs affect the rotation of the Earth because of what is known as the moment of inertia, or rotational inertia.

The phenomenon is not abnormal — a shift in any object’s mass on Earth relative to the axis of rotation will change a moment of inertia, though most are too small to be measured.

NASA'S JET PROPULSION LAB

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If filled, the gorge would hold 40 cubic kilometers (10 trillion gallons) of water. That shift of mass would increase the length of day by only 0.06 microseconds.

Based on the evidence from this study, we can rate it as...

THE RATING

RATING:

TRUE