Frex, we have no idea why the expansion of the Universe is speeding up. I think some theories believe that may be due to something like antigravity being generated by empty space.
It's a boson, as for I know fermions have got anti-particles, not bosons. This said, about gravitons, I would remind that gravitational waves have been detected [with a suitable degree of certainty], this suggests something. So, more than anti-gravity, we can imagine to make an object "neutral" to gravity, if we understand how to interfere with the Higgs field to avoid that an object has got a mass [trusting electromagnetic force to keep it together! But if the object is more little than a mountain, this is possible]. This would mean that a spaceship could ignore gravity and it would need a very tiny amount of energy to accelerate and leave the planet. Imagine to accelerate an object with mass = zero [m = 0]. The force is mass multiply acceleration ... if mass is null, you need a null force to accelerate to infinite! [Actually to the speed of light, but if the spaceship has got no mass, also the relativistic mass is null, not tending to infinite while the vehicle approaches the speed of light, so that it would be theoretically reachable ... with a nice "null" as result of the equation of the relativistic mass].
And how do you account for cutting huge stones to such tight tolerances that cannot be easily duplicated with today's technology ?
There is no such thing as solid matter, matter consists more of empty space than matter, research the space between the nucleus of an atom and it's electrons.
