"Gravity" is not, itself, an entity that travels. A disturbance in a gravitational field, however, does propagate at c. Not faster.
It depends on what you mean by "travel". Gravity, as the attraction between masses, is a field ( or a curvature in space-time in GR), Light is a radiation. Light has a field associated with it, the electromagnetic field, which is what is responsible for the force interaction between charges and magnetic poles. Gravity has a radiation associated with it, gravitational radiation ( the gravitational waves detected by LIGO) It doesn't make sense to compare the speed of a radiation with the "speed" of a field ( a field is just "there" and doesn't have a speed) In each case, the radiation is due to "ripples" propagating through the field, and in both cases, they travel at c. Photons and gravitons are quanta of their respective radiations. While you will hear gravitons being referred as the mediating particle for gravity, this means virtual gravitons. In the same way, under QED, virtual photons are the mediators for the electromagnetic field. (Though to be fair, gravitions are still hypothetical as we have not of yet been able to gather gravity into the quantum fold. ) In essence, electromagnetic waves carry information about changes in the electromagnetic field, while gravitational radiation carries information about changes in the gravitational field.
The Speed of Gravity is the speed of light, we were taught during physics class, this can be found by solving for the velocity of gravity from the Newtonian Equation, if the Sun disappeared the gravitational effect would be felt at the same time you saw the sun's light disappear. Which can also be found in the equation for Schwarzchild Radius of a Black hole as "C" being the velocity of gravity term. Please Register or Log in to view the hidden image! For a better explanation read, Link = http://blogs.discovermagazine.com/d-brief/2017/12/08/speed-of-gravity-light/#.XPvqSIhKjIU
If you are using 'gravity' as a propulsion device, not sling-shot, then YES. MANY MANY TIMES FASTER THAN LIGHT.
I assume this is a reference to "warp drive". If that turns out to be possible, then it won't be so much that things are travelling faster than light in space, but rather that the space itself is being compressed and expanded to move an object rapidly from one region of space to another.
I wish I understood the equations posited in the warp (aka; Alcubierre) drive. The only general attribute to the theory, I understand, is that it requires negative mass (not antimatter as you and others already know). Since negative mass itself is undiscovered, the warp drive concept cannot move forward to a "testing of concept" phase. Does anyone have an opinion if, hypothetically, a ship within the warp bubble would be immune from external gravitation? Like if it traveled near a BH, or neutron star, would it be unaffected while in the bubble? Thanks for all feedback on helping me advance my knowledge!
