NASA scientists explain how dam in China affects Earth’s rotation

In a 2005 NASA post, when the Three Gorges in China was still under construction, Dr. Benjamin Fong Chao of the American space agency’s Goddard Space Flight Center used the megastructure as a reference point to measure the planet’s mass displaced by the massive tsunami that hit Indonesia in December 2004.

Completed in 2006 on the Yangtze River, the longest dam in Eurasia reached full capacity when all generating units were commissioned in 2012. The complex uses water flow from three nearby gorges (Qutangxia, Wuxia and Xilingxia) to turn turbines that generate electricity.

Fong Shao’s 2005 paper explains how such a change (in this case, 40 trillion liters of water) could affect the Earth’s rotation. The explanation uses the physical principle of the moment of inertia, which, when reduced, allows an object to spin faster. This is essentially what makes an ice skater spin faster when they bring their arms closer to their body.

How China’s dam is changing the world’s rotation

The physical principle of moment of inertia is what explains how the Earth’s rotation can be affected after an earthquake due to the movement of tectonic plates. In the case of the catastrophic Indonesian tsunami, NASA scientists determined that the tremor It shortened the length of the Earth’s day by 2.68 microseconds.

Applying the same basic concept to the maximum capacity projected for the Chinese dam at the time, the NASA geophysicist calculated that the mass change (today’s reality) would increase. It would lengthen the length of a day by 0.06 microseconds and shift the position of the Earth’s pole by about 2 centimeters..

The impact of this effect is incredibly small. To get an idea, consider how much time a 0.00000006-second time interval represents in our daily routine. Even compared to other events, such as the tsunami that killed 230,000 people, the impact is minimal. But the worrying thing is whether change will happen. is the result of a man-made structure.

Global warming also affects the rotation of the earth

Of course, humans’ impact on Earth’s rotation is not limited to the Three Gorges Dam. Other events, such as climate change, also affect the planet’s mass distribution. This is currently happening with the melting of glaciers Bringing the water mass previously stored at the poles directly to the equator.

Some studies predict that increasing greenhouse effect could cause the Earth’s rotation rate to gradually slow down beyond what the Moon traditionally produces, resulting in longer days and unbearably high temperatures.

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