I sure missed that one,
came after I finished school (and I know that I have not kept up with new thing in that direction.
thank you for the updated info
and is it just me, or does dragging space time sound identical to some ether theories ?
No, gravitomagnetism isn't like ether theories because ether theories postulate an absolute rest frame that doesn't exist, and efforts to detect an "ether drag" as the Earth moves through the ether have been disproved.
Technically frame dragging is a purely geometric phenomenon. But differential geometry is difficult to work with and there's a more intuitive way of thinking about it, known as gravitoelectromagnetism (GEM).
In the weak field limit (where gravitational fields are fairly weak like they are around the Earth and where velocities are much less than the speed of light), the laws of gravitation can be expressed in the same form as the equations for electrical charge interaction and electromagnetic induction - with the exception that the sign of the interactions is reversed.
This means that gravitation acts analogously to electric charge, and in fact it may be more accurate to call "mass" a "mass charge" instead. With gravity like mass charges attract, and unlike mass charges repel - the opposite of electrical charge interactions. Other than this inverse sign of the interaction, the Coulomb interaction equation is identical in form to Newton's equation for gravitational interaction (and as we know, Newton's gravity equation works fine in the weak field limit for calculating the acceleration of the gravitational interaction).
Here's where it gets interesting: we can model any of the effects that we see with electrical currents and charges and induction phenomena, with gravitation as well, because the two are perfectly analogous in the weak field limit. One popular way to imagine this, is to draw an analogy between an electrically conducting wire, and a hollow pipe with a massive fluid flowing through it. So for example, if we create a coiled pipe in the shape of an electrical inductor, and run a very dense fluid through it in one direction, we've created a gravitomagnetic field in the same shape as the magnetic field around an inductor. Or if we oscillate the direction of fluid flow through that coil back and forth, we can create an alternating gravitomagnetic field that will radiate gravitational waves, just as an alternating electromagnetic coil will radiate electromagnetic waves.
In 1963 Robert L. Forward published a brief but fascinating paper called "Guidelines to Antigravity" that took this concept one step further, and proved that antigravity is a real physical phenomenon. Which is probably why it was almost completely ignored by mainstream physics, when it should have been hailed as a momentous discovery. His idea was very simple and absolutely convincing, and it goes like this:
If we wind an electrical coil around a hollow toroidal form (a toroid is shaped like a donut), and send an increasing electrical current through that toroidal coil, we create a dipolar electrical field: on one side of the hole of the toroid we find a positive electric field, and on the other side we find a negative electric field. The same principle applies to gravitation - if we replace the electrical winding with a hollow pipe and run a very dense fluid through it at an increasing (or decreasing) rate, we create a positive gravitational pole on one side and a negative gravitational pole on the other side.
In other words, a body of matter placed near the negative gravitational pole will be repelled away from the toroid - we've created an antigravitaitonal field.
Sadly, the coupling constant of gravitation is so incredibly small that it would take a fluid with a very high density flowing at high speed through large pipes wound into a gigantic toroidal shape (say, the size of a football field), in order to detect this effect. So we've never been able to try it out, but we know that it would work because the equations are very straight forward, and well-proven at this point via various astronomical observations and NASA's Gravity Probe B experiment.
Robert Forward understood this problem of magnitude, and proposed another very interesting idea as a potential solution: he suggested that it may be possible to develop a material with a high and nonlinear gravitomagnetic permeability, as an analog for the iron core that we use to amplify the magnetic fields produced by a magnetic coil. I assume that this is possible. But to the best of my knowledge nobody in the public sector has ever developed anything like that, and it would still take an extremely dense fluid, and preferably one in a superfluid state, flowing around a very large toroidal shape, to produce a detectable dipolar gravitational field - unless we could develop a material with outrageously high gravitomagnetic permeability. And nobody knows how to do that.
But I hope they develop such a technology one day. Imagine how cool it would be to have an amusement park "ride" where you could float in an gravitational field for awhile, before the fluid through the pipes began to lose acceleration and you floated back down to the ground. That's physically possible, but it's still an engineering challenge beyond our technological means.
It's worth noting that the rate of time would also be affected by such a device: time would be very slightly dilated (slowed down) on one side of such a device, and time would be slightly accelerated on the other side of the device. So an observer looking outside from their position within the positive gravitational pole would see the world around him speed up slightly (you'd probably need a pair of highly precise clocks inside and outside of the field to even detect it), and observer within the negative gravitational pole would see the world outside of the field slow down slightly.
It sounds like pretty wild stuff, but it's all 100% legit gravitational physics.