We really can't reach any actual conclusion at this point. We may say today that interstellar travel is impossible, but tomorrow we may find a solution. We ma

We really can't reach any actual conclusion at this point. We may say today that interstellar travel is impossible, but tomorrow we may find a solution. We may say today that we are alone, only to be visited by intelligent aliens somewhere in the next millennia. We may never be visited by anyone or visit anyone, but the universe may be full of intelligent life. We simply cannot compute anything for such a problem, with so many unknowns.