Q-FFF theory is an alternative rigid string theory based on 3D Higgs torus particles, able to 
mutate into rigid /stiff Electron-Positron propeller strings, and rigid Photon strings, 
which can interlock into Quarks. see:
Quantum FFF
Theory ( Function Follows Form) and Relativity. 
Mass is the
capacity of rigid stringy Fermion particles to mutate oscillating Higgs vacuum
field 
particles into as many rigid gravitons per time unite in a continuous
collision process.
The collision
process is assumed to be the origin of the spin and eigen energy of Fermions
and 
fully in line with General Relativity (GR).
Around
massive objects like stars and planets, the Higgs field oscillation strength is
diluted and 
polarized by the graviton radiation influence, creating a "Local Anti Symmetric Oscillating vacuum 
Frame" ( LASOF) as originating a so called
lightspeed drag effect, which seems to be not 
in line with GR.
Black holes
do not emit gravitons but consume the Higgs vacuum field. 
The diluted vacuum
field around black holes should have comparable LASOF effects on 
the light
speed in combination with a quantum gravity effect.
As a
consequence, it is assumed that the LISA (Pathfinder) probe soon will be able to test l
ight
speed differences around the sun even at its orbit location L1 ( Lagrangian L1)
and as a 
result its absolute speed related to the local LASOF vacuum of the
sun.
ESA/NASA Laser Interferometer Space Antenna ( LISA)
 
Second
difference with GR is that Fermions feel Resistance and Propulsion from the Higgs 
field compensating each other and guide by “a Lorentz polarization effect” of
the propeller 
shaped fermions, polarizing into the Higgs ether wind. (See image: Quantum gravity and inertia)
 Quantum gravity and inertia.