The infinite discussion about the topic: "Are we alone in the universe?" continues.

The infinite discussion about the topic: "Are we alone in the universe"?continues maybe forever. Maybe the human descendants who look at the white dwarf that once been the Sun continue this discussion. And when our descendants move to another solar system. 

They face the model that they turn aliens into each other. When the sun explodes a nova eruption is the final moment for our descendants that they must leave. Or they can let the sun destroy them. In that moment. The sun used all its fuel. 

Before that moment the sun turns into a red giant, and maybe that species will move to a longer distance from the sun. That species will not be like humans at all. Genetic engineering and controlled evolution cause that. This futuristic species will not be like we are.

We must wake up and think about the game theory. The idea of the Game theory is that all individuals and species want to maximize their benefits. The alien species should follow the game theory model. And they also want to maximize their benefit. 

Are we alone in the universe? This is an interesting discussion. We are alone until we get an answer, that might come tomorrow, or we might ever get an answer or make contact with another civilization. And that is a paradox, we search for extraterrestrial intelligence until it answers. The human lifetime is not infinite. And maybe the answer comes a day after our funerals. That means we would live our entire lives without the contact. 

Are we alone in the universe? We can say that the discussion is infinite. 

That discussion continues until we find another civilization, and that thing can never happen. The fact is that we haven't found another civilization. Things like radio signals from Proxima Centauri. And especially WoW! The signal is evidence. But is there evidence that supports or denies the existence of ETI (Extraterrestrial intelligence)? 

The fact is that those signals happened only once. That can support the hypothesis. That there was some kind of intelligent origin. And the same thing denies intelligent lifeforms. There are no unique chemical reactions in the universe. So those signals should repeat, but they never happened again. 

Alone in the universe can mean, that we have no alien contact. And if the nearest civilization is 2000 light years from us. That means that making a call to them is difficult. It's possible. That the transmitting power of our telescopes is not enough. 

The signal travels between Earth and other civilizations for 4000 years. The data transmission to that star takes 2000 years. And then the alien response takes 2000 years. And that requires lots of power to create a radio signal that travels between Earth and that distant world. 

This is the reason why those signals are interesting. But are we alone in the universe? The thing is that we should determine "alone" before we continue. Are we alone in a flat, where we live? That is an interesting question. There could be lots of people in the same house. Where we live, but we never discuss it with them. Some researchers calculated that there are about 38 intelligent civilizations in our galaxy. There are about 100-400 billion stars in the Milky Way. And 18% of them are like our Sun. 

So here is about 18-72 billion sun-type stars. And if there are only 38 intelligent civilizations. The possibility that we find those civilizations is very low. If we just listen to those G-2 spectral-class stars we must select the right stars. Then we must separate the alien signals from other natural signals. Here we think that they are precise like us. We believe. That the law book is similar. And they think and use the same methods as us. We are also aliens to those other civilizations. 

Stephen Hawking said: if an alien calls, don't answer. 

The biggest thing is that if we make contact the wrong way. We can risk our entire species. SETI uses passive systems, and the reason for that is that those hypothetical aliens can be hostile. There is always the possibility that those aliens are dangerous. But then we must say that we are aliens to those other, still hypothetical species. We are aliens to them, and in the same way, they must be sure, that we are not dangerous. 

In this hypothesis, the 38 intelligent species travel in our galaxy without saying anything to each other. In this model, only civilizations that form in the same solar system can discuss with each other and trust each other. Those civilizations know each other. But if the civilizations don't know each other before the message comes, they don't know anything about their opponent. There must be trust that the opponent is friendly and that those species will meet. 

And then there would be a long time before those species see each other. There is a long journey from the first contact to the first interstellar embassy. And that will take generations from the first contact to the first meet. Both civilizations need time to adjust themselves to the level. That they can exchange information. And discuss with each other. 

The contact with that other, still hypothetical species could also be the first contact with other civilizations for that alien species. We must think that maybe we are their first contact.

The fact is this. If those, still hypothetical humanoids, notice our signals they face a similar problem, that we face. And the biggest problem is, is the sender of signal friendly, or is that sender hostile? Maybe we are a friendly species in our movies. But humanoids have never seen us before. They must also analyze data before they decide to answer. 

And the big advice is this: we should not answer either. We don't know: are aliens hostile or friendly? This means that those aliens might not answer either. Because they are afraid of us as much as we are afraid of them. If we someday get a confirmed message from the aliens, we must understand that that message is probably not meant for us. It might meant for alien internal messages.  

https://bigthink.com/starts-with-a-bang/unsurprising-non-detection-intelligent-aliens/