# Where is Earth's center of mass?

#### moonman239

As a first-order approximation I can simply calculate the location and radii of an ellipsoid that contains the center of mass, but that's not good enough. Doing a Google search for "center of mass earth" doesn't pull up anything.

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#### Doc Al

Mentor
As a first-order approximation I can simply calculate the location and radii of an ellipsoid that contains the center of mass, but that's not good enough. Doing a Google search for "center of mass earth" doesn't pull up anything.
It's unclear what you are looking for. Are you looking for the actual location of the earth's center of mass, taking into consideration non-uniform distributions of mass density? (As a first approximation, why not say right in the middle! )

#### Klockan3

Why are you looking for this information, the center is a very good approximation...

#### moonman239

It's unclear what you are looking for. Are you looking for the actual location of the earth's center of mass, taking into consideration non-uniform distributions of mass density? (As a first approximation, why not say right in the middle! )
Yes.

#### DaveC426913

Gold Member
What coordinate system would you use to define the location of the centre of mass?

I mean, would you say it's X miles from the North pole at sea level, Y miles from 0 lat 0 long?

The coordinate system is the surface of the Earth, which is not a sphere?

#### D H

Staff Emeritus
Doing a Google search for "center of mass earth" doesn't pull up anything.
That's the wrong search term. The right search term would be "geocenter" were it not for a slew of companies and organizations that erroneously think they are the center. You'll get a lot of irrelevant garbage if you just search for "geocenter".

Try searching for "geocenter motion" or "geocenter variations".

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