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>>I never heard of a "speed of gravitation"; and it is confusing, at the least, to try to compare gravitational force (N/kg or m/sec^2) with a speed, like the light speed (m/sec).
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>On earth at sealevel we express gravity as being 9.8m/sec^2, this also assumes an absolute velocity...

No, why should it? The same acceleration would be measured by different observers, moving at different speed - each one assuming he is at rest.

Let me give an example. Let's round the gravitation to 10 meters per second square.

From the point of view of a person on Earth, the object starts at rest; one second later, the object has a speed of 10 m/s. Acceleration: 10 m/s in one second, or 10 m/s^2.

From the point of view of a person that is moving upward at 20 m/s (at a constant velocity) (the person, of course, is assuming that he is at rest), the object starts moving downward at 20 m/s. One second later, the accelerating object has a speed of 30 m/s downward. Once again, the object has changed its velocity by 10 m/s in one second.

For another person that is moving downward at 30 m/s, the object starts with an upward speed of 30 m/s. After one second, it has an upward speed of 20 m/s. Once again, there is a difference of 10 m/s, in one second.

And so forth.

> from very recent tests they are saying that this absolute velocity this approx 20 times the speed of light.

Physicists usually agree that an absolute velocity doesn't make sense. About the closest we can get to any "absolute velocity" is our velocity in relation to the background radiation; if we say that an absolute velocity doesn't make sense, this might be interpreted express our velocity with respect to the average movement of the Universe. Differences in the background radiation, in different directions, indicate a velocity, of the Solar System, of some 700 km/sec, IIRC. Note that this is more or less 0.2% of the speed of light in a vacuum.