Gravity and Rotation: Exploring the Milky Way's Mass Increase

[ndvcxk]

Science news recently reported milky way rotates faster than thought - hence more mass. How does this work out for a single planetary body: If rotation is accelerated, my thought was: less gravity, bec. higher centrifugal force. Now, I'm thinking - more mass due to rotation hence more gravity. For discussion, let us assume an earth-size body made of identical solid material which cannot "fly-off", no geostrata with different properties.

On a sidenote, if the rotation->mass increase is correct, we should be able to decrease gravity here on Earth below an elevated, smooth, large globe, as we let it spin fast. Has this been tried ?
Thx for comments !
Mike

 

[lippyka]

The increased mass of the Milky Way due to faster rotation does not directly have an effect on a single planetary body like Earth. The increase in the mass of the Milky Way would cause the gravitational pull on Earth from the Galaxy to be slightly stronger, but the difference would be negligible. However, the faster rotation of the Milky Way can indirectly affect the gravity experienced by a single planetary body. For example, if two large galaxies merge and the resulting galaxy rotates faster than before, the increased rotation can cause space-time to warp, which can affect the gravitational field around a single planetary body. This phenomenon is known as frame-dragging and has been observed around Earth. In terms of decreasing gravity here on Earth, it is theoretically possible to decrease the gravity experienced by an object by spinning it very quickly, as you suggested. This is known as the centrifugal force and is due to the object's inertia. However, this would only be effective at a very small scale, as the effects of the centrifugal force are negligible compared to the gravitational pull of Earth.