The Three Gorges Dam in China is a true engineering marvel. However, according to NASA, filling it could cause an unexpected effect. Which ? It could cause the Earth’s rotation to slow down. Here are the details!
The Three Gorges Dam could exert a much greater influence on the planet than previously thought. According to NASA, the filling of this gigantic dam could have slowed down the rotation of the Earth. Although it may seem surprising, this hypothesis is based on sound physical principles and precise scientific data.
This dam located on the Yangtze River in Hubei province is the largest hydroelectric power station in the world. It was built in 2012 after almost 18 years of work. Furthermore, it measures 2,335 meters long, 185 meters high and can contain up to 40 cubic kilometers of water, or 40,000 billion liters. It is a colossal mass whose impact on the Earth’s rotation has been observed by NASA researchers.
That role does the moment of inertia play in the rotation of the Earth?
This theory is rooted in a NASA study from 2005. At that time, researchers were examining the impact of the 2004 Indian Ocean earthquake and tsunami on the planet’s rotation.
They found that this earthquake which had moved the tectonic plates modified the distribution of masses on the surface of the Earth. This at the same time changed its moment of inertia.
The moment of inertia is a physical property that determines the resistance of a body to any modification of its rotation. A simple example to understand this concept is that of a figure skater who, by bringing his arms close to his body, accelerates his rotation. In the same way, the Earth can see its rotation modified by variations in the distribution of its mass.
NASA scientists have demonstrated that the 2004 earthquake had reduces the length of a day by 2.68 microseconds. Theoretically, a massive change in water distribution, such as that caused by the Three Gorges Dam, could result in comparable effects.
Dr. Benjamin Fong Chao, a geophysicist at NASA’s Goddard Space Flight Center, says filling the dam could move the Earth’s pole by about 2 centimeters. Furthermore, it could slow down the rotation of the Earth, increasing the length of a day by 0.06 microseconds.
Subtle but notable human impacts on Earth’s rotation
Certainly, the changes observed are minimal, but their significance remains significant. They emphasize the influence of human activities on the planeteven on phenomena as vast as the rotation of the Earth.
For example, climate change has also changed the distribution of masses on the Earth’s surface. As a reminder, this caused the ice to melt at the poles and rising ocean levels in tropical regions. This is what influenced his rotation.
The melting of the ice generates a mass transfer from the poles towards the equatorwhich slows down the rotation of the planet. It is also interesting to note that the slowing of the Earth’s rotation was already observed even before the construction of the Three Gorges Dam.
This is especially the case of the gravitational pull of the Moon and other natural phenomena. However, although the impact of the dam is minimal, it adds to these factors and contributes to an overall slowing trend.
Thus, megastructures like the Three Gorges Dam, in addition to natural phenomena such as earthquakes and climate change, collectively influence the rotation of the Earth.
So, what do you think? Share your opinion in the comments!
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