Here I AM telling you an INTERESTING fact about our Earth's Rotation.
Do you Know "Three Gorges Dam" ( China) has slowed down the rotation of the Earth!!!
China’s Three Gorges Dam is the
world’s largest hydroelectric station. It is a structure that stands as a
testament to the tenacity of human ingenuity. First envisioned in 1919
and finally completed in 2012, the dam spans the Yangtze River and measures 2.3
kilometers (1.4 miles) long and 185 meters (607 feet) tall. Almost 30
million cubic meters (just over 35 million cubic yards) of concrete and 463,000
tons of steel were used to erect the massive structure.
With a
ridiculous reservoir that runs for 660 kilometers (410 miles), the dam raises
water to 175 meters (574 feet) above sea level. The amount of water
displaced when the dam is full weighs about 39.3 TRILLION kilograms (or around
86 TRILLION pounds). Yeah, it’s huge.
What
does a dam have to do with the Earth’s rotation?
What it comes down to is
something called moment of inertia. Essentially, this is a property of
rotating bodies that can tell us how easy (or difficult) it is to spin
something.The moment of inertia of an object
depends on a few things.One,it depends on an object’s shape and the
point about which it’s rotating.It also depends on an object’s
mass and how it’s distributed.
For our purposes, let’s focus on the
mass distribution property of moment of inertia. If two balls are the same size
but different masses, the lighter ball rotates more easily than the heavier
one. What happens, though, if we displace some of the mass?
Imagine a figure skater. They
displace their mass by bringing in or extending their arms upon rotation to
speed up or slow down.If you’ve got a good visual, you can see “arms in”
is fast and “arms out” is slow. If the weight moves away from the axis of
rotation, the rotation is slowed. This is pretty much what the Three
Gorges Dam has accomplished by displacing all that water!.
NASA scientists calculated
that shift of such as mass would increase the length of day by only
0.06 microseconds and make the Earth only slightly more round in
the middle and flat on the top. It would shift the pole position by
about two centimeters (0.8 inch).
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