I have as advised done some catching up on basic cosmology, looking at various discussion and lectures on the nature of the universe. Something that has always played on my mind, is that i remember reading and watching a documentary about the potential to achieve the velocity of light. It was discussed that to accelerate an object to the speed of light would require infinite energy, as the object would exponentially gain mass. it is my understanding that photons are massless so there is no issue with lights ability, but when it comes to galaxies it is more confusing. is the acceleration due to the kinetic energy of the initial bang( if thats the model) or is it due the material and it's density pushing them away at that velocity? And if we are not at the centre of the universe are we not moving away from someone else's galaxy at the speed of light?