I am very skeptical about the time/distance argument used to rebut the possibility that we are being visited by aliens from a far away galaxy. Our understanding of physics certainly incomplete, and the argument is necessarily based on only what we know, but yet supposes absolute limitations based on what we do not know. For example, when astronomers considered the life span of our Sun in the 19th Century, they knew nothing of nuclear physics. The best explanation they had for its brilliance was that it was a lump of coal. Based on this, they thought that it had been burning for less than five-thousand years, and had perhaps another five-thousand years left to burn.
I completely agree with you. I have a lot of questions about what we think we know about the universe and Physics across the universe. Space is expanding and within that expansion light travels at a constant speed but can be manipulated by gravity? At what speed is space expanding? (for instance). Does gravity behave the same way related to mass in all parts of the universe or the even our galaxy? We determine and measure most of what we know about the universe based on what we have been able to observe and experiment with in our tiny little solar system.
Knowing that everything in the universe is moving while “space” is expanding makes finding a truly stationary point of reference impossible over a period of time to consider long distance travel. That is, unless we presume that there is a way to instantly travel to a spot in the universe.
If we want to create theories to explain what our known science can’t, we can assume spiritual beings, trans-dimensional beings, and all sorts of fun stuff.
I enjoy considering the potential and imagining the incredible. But, even with the multitude of questions about the science we know, I can’t conceive a pseudo scientific way that advance species could communicate and interact physically.