Earth on the development ladder

Could it be that in the beginning of the Universe, life developed in the core, and has spread by hopping on comets and asteroids and space dust from closer objects (such as mars). Is this why objects farther from the gravitational pull of the sun such as mars and Europa could have theoretically developed life much earlier than Earth? Could there be a bacterial Adam and Eve untold eons before?

concidering the universe is about 15 billion years old, and estimates put the earth at 5 million years old. and a wandering "comet" could travel at obital speeds of around 20,000 mph at its best and some how travel the estimated 30 million light-years from the center of our galaxy to earth?

Sorry, but you really need some sort of FTL travel for that to happen