Except for a Dark Forest strike ...
If Einstein was right ( and there is no evidence he was wrong) then the visit to Earth from aliens who exist hundreds of light years away is impossible. (yes impossible). No biological or mechanical entity could travel such a distance and arrive intact given the laws of physics. The fastest anything can travel is the speed of light. Anything more dense than a photon could never even get close to the speed of light. A light year is the distance traveled by a photon at 186 thousand miles per second over one year. The only aliens you need to worry about are those that don’t share your national and cultural heritage. They are right here on earth and have access to all sorts of advanced technology.