The models of alien civilizations could be the civilization of humans in the distant future.
During the interstellar flight, evolution has time to work
When we are creating models of an alien civilization, we are also creating models, what our civilization might look like tomorrow, and if we are thinking about the possibility to create stable colonies in our solar system and farther in the universe. The thing is that sooner or later every each of the stars spends its nuclear fuel and if the star is like our sun, it would end it's life as a nova, which means that the end is as the white dwarf.
The bigger star would end it's life as a supernova. And if we are thinking this kind of thing at the point of view of evolution, that means that the citizens must flee from its planet or it must be terminated. In many models, the civilization can advance only in the planets, what is orbiting the yellow stars, what can live long enough. So the model could be wrong because there is a possibility that even the short-living blue star might have the planet, where is intelligent life-form.
And if the intelligent life form is curious and it observes it's a star, it might notice that the end is near, and start to create the giant space arks, what it can use for evacuating. During this process, the civilization would terminate the non-wanted genetic material, and that means that the controlled evolution would make them different than they were at the beginning of the process. If that kind of civilization would put all its knowledge, and intelligence to that operation, it can survive. And when the entire civilization moves to the artificial planets, what the giant spacecraft are, there are not similar problems than in conventional space journeys. The scale of those projects is so huge, that we cannot even think that we would do that in modern days.
But maybe in the distant future, we or our descendants are facing the situation, that they must leave this planet. And at least, when our star the sun would be ending its life as a star when it explodes as a nova, the civilization must leave the solar system to finding new energy sources. In some theories, the civilization would move to farther planets, when the star is growing, and in those scenarios, we have forgotten, that there is a possibility that solar system might have only one planet.
But this kind of thing is pure speculation. There are many other models about civilization and the thing is that we could be that "alien civilization" in the day tomorrow. If we are thinking the hypothetical space civilization, that civilization might use 100 % of the energy of some star by simply closing the red dwarf in the giant ball, what is covered by using the silicon panels, and that giant structure can send energy to the alien crafts by using very powerful masers or electron cannons.
There are many forms of the theoretical alien civilizations
Could the hypothetical alien civilization consist of two groups of aliens? The planetary and space race. The other group lives in planets, and other group lives in spacecraft, and they would ever land to the planets. There is a possibility, that the aliens could hybridize with their spacecraft. If the aliens would have a collective mind or consequence that means that it would eliminate the rebellion or violence. The thing is that the collective mind would benefit the community.
But individual intelligence could danger the mission. This is the paradox of the hypothetical extremely long term missions, which could take even millenniums. One of the things, that we must realize when we are thinking about the hypothetical alien civilization, what might be traveled between the stars, is that those creatures might not make that thing for fun. They must have a reason for those journeys, which will take even millenniums. That thing means that the crew of those crafts might face the evolution, what we cannot even imagine.
When we are thinking about things like the physiology or brain capacity of aliens, we must realize, that those creatures might be intelligent as a group. This means that the creatures might have microchips in their brains, and those microchips make them the ability to communicate with the computer of their craft, and in this case, they could have collective knowledge in their craft. The central computer would have the role, that it connects the nervous systems of those hypothetical humanoids, but the individuals would be like handicapped.
The hybridization with spacecraft
Or there is a possibility that the evolution in the bodies of those creatures would make their nervous system communicate spontaneously with the wireless data system of their craft. That means that those creatures would be hybridized with their craft. At this moment many of you will say, that the evolution would need a very long time to modify their bodies. But if the journey will take tens of thousands of years that means, that evolution would have the time to make those modifications.
And there is created a model, that the evolution of that crew would be controlled. In this scenario, the aliens would first travel a long time near their home star, and in that period the controlled evolution would hide the origin, where those creatures would have left for protecting their species. That's why they had to modify their bodies for hiding their origin. But this is only a hypothesis, nothing more or less. Just hypothesis, but the hypothesis is the road to theory, and theory is the road to a practical solution. That means in the future, we might be that alien civilization, what travels in the stars.
