I read that the Sun will become a red giant and destroy the Earth in about 5 billion years. If this is correct, is there any possible way that a vastly advanced alien civilization that exists in a galaxy 6 billion lights year away could ever reach the Earth and make contact with human civilization in the present or in the Earth's future? If the aliens had a spaceship that could travel at near light speed, would time dilation make such a journey possible or would time only slow down for the spaceship and its occupants and not the destination of the spaceship, Earth? If somehow the aliens could go faster than light speed which I know isn't possible according to our present understanding of physics, is there any relationship between time slowing down for the spaceship and its ability to reach Earth before the Earth is destroyed? My understanding is that time dilation wouldn't affect the Earth and thus, it's a true statement that no alien could ever reach the Earth unless it started traveling to Earth from a distance of less than 5 billion light years? If that's a true statement, could it be a feasible explanation as to why human civilization hasn't made contact with any alien life-forms? As a follw up, if the universe is expanding at any accelerating rate, then can we also conclude that the number of galaxies within 5 billion light years of the Earth will continually decrease so that the more time passes, the less likely it is that Earth will be visited by advanced alien life forms?