Change in orbit due to moment of inertia change?

[DrBwts]

Hi,

So recently I read about the massive 3 gorges dam changing the mass moment of inertia of the Earth to such an extent that the days will now be 60ns longer.

Then I thought, how will this effect the orbit of the Earth about the Sun?

Any thoughts?

 

[SteamKing]

Wow! A whole 60 ns longer each day! Man, I can catch some additional zzzs every morning!

I wouldn't worry about any orbital changes w.r.t. the Earth's movement about the sun.

BTW, in 60 ns, a beam of light travels about 18 meters.

It would also take over 160 million years to add an additional HOUR to each day.

 

[D H]

Then I thought, how will this effect the orbit of the Earth about the Sun?

It won't. It hasn't changed the Earth's mass one iota, nor has it changed the distance between the Earth's center of mass and the Sun.

 

[BruceW]

what about tidal locking effects between the Earth and the sun? I guess it is negligibly small, since the size of the Earth and sun is very small compared to the distance between them.

 

[PJC01]

I find this topic very interesting. The change in the Earth's mass moment of inertia due to the construction of the 3 gorges dam is a significant event that will have an impact on the Earth's rotation. The Earth's rotation is closely related to its orbit around the Sun, so any changes in the rotation will also affect the orbit.

The mass moment of inertia is a measure of an object's resistance to changes in its rotation. In this case, the construction of the dam has shifted the Earth's mass distribution, resulting in a change in its moment of inertia. This change will cause the Earth to rotate slightly slower than before, leading to longer days.

In terms of the Earth's orbit around the Sun, this change in rotation will also have an effect. The Earth's orbit is governed by the laws of gravity, which take into account the mass and distance of the Earth from the Sun. As the Earth's rotation slows down, the distribution of its mass will also change, causing a slight shift in its orbit. However, this change will be very small and will not have a significant impact on the Earth's overall orbit.

It is important to note that the Earth's orbit is constantly changing due to various factors such as gravitational interactions with other planets, the Sun's own movement, and even the Earth's changing mass distribution due to natural phenomena. The change in the Earth's mass moment of inertia due to the 3 gorges dam is just one of many factors that contribute to the Earth's ever-evolving orbit.

In conclusion, while the construction of the 3 gorges dam may have a small impact on the Earth's orbit, it is not something that should cause concern. The Earth's orbit is a complex system that is constantly changing, and this change in the mass moment of inertia is just a small piece of the puzzle. As scientists, it is important for us to continue studying and monitoring these changes to better understand our planet and its place in the universe.