Solar systems like our own might be quite rare.

The image of the external solar system above this text introduces the system where are seven earth-type planets. There are the best chances to find extraterrestrial lifeforms. But there is a difference between intelligent extraterrestrial lifeforms and intelligent extraterrestrial lifeforms. If somewhere is another civilization they might be very far from us. And that thing brings interesting visions to the mind of people. 

The nearest known solar system that is similar to us is 3000 light-years away. And that means the solar systems that are like our own might be quite rare in the universe. Sometimes wise men are asking the question that should the solar system where are intelligent lifeforms have 8 planets like in our solar system and should the names of the aliens "Jack" and "Jill". 

The fact is that if we would send the message to that solar system, that is 3000 light-years from us. The message will travel there 3000 years. And the answer would take another 3000 years to travel to our solar system. So we should think what was the level of a human civilization 3000 years ago. And 6000 years is a very good time to advance. 

https://scitechdaily.com/stellar-contradiction-solar-systems-like-ours-may-be-quite-rare/

https://www.theverge.com/2017/2/22/14674088/7-planet-solar-system-discovered-conditions-for-life-water-nature-nasa

Image: https://www.theverge.com/2017/2/22/14674088/7-planet-solar-system-discovered-conditions-for-life-water-nature-nasa

"Artist’s conception of the central portion of the Next Generation Very Large Array. Credit: Sophia Dagnello, NRAO/AUI/NSF" (https://scitechdaily.com/10-year-astronomy-plan-calls-for-massive-new-observatory-to-study-exoplanets-and-black-holes/)

And then the question that repeats one time after one: Are we alone in the universe?

The thing is that there is the possibility that the nearest civilization is about 3000 light-years from us. So that means we would not have a chance to communicate with that civilization. 

The thing is that the distance to other civilizations would be even bigger than this 3000 light-years. So when we are asking the question: are we alone in the universe we should also ask the question: what if we are alone in the area where we could communicate with aliens by using systems that exist. 

The thing is that there is another civilization in the universe.  But if that civilization is thousands of light-years away from us that civilization cannot affect us. Or we cannot affect that civilization. The thing is that there are billions and billions of stars in billions and billions of galaxies. So for being alone we would be a little bit too lucky. 

If we are thinking that there are two similar solar systems to our solar system in every galaxy. There are lots of similar planets to Earth if we are thinking of the scale of the universe. In this case, I meant for intelligent and technically advanced lifeforms. 

https://scitechdaily.com/are-we-alone-in-the-universe-nasa-calls-for-new-scientific-framework-in-search-for-extraterrestrial-life/

The lifetime of civilization is one of the most interesting things. 

In the theories of the advancing of the civilizations, every single civilization must pass the test for reaching the Kardashev scale. The first test is that the leaders of the hypothetical civilization must realize that the things like interplanetary travel require nuclear technology. That technology is easy to transform as a weapon. 

And those weapons might cause that the civilization would commit suicide. But if that civilization finds the common goal they would reach the first step to Kardashev scale and learn to flight between planets. The second test would be when the civilization would start to make colonies to other solar systems. 

In that case, there is the possibility that there would be a conflict between the civilization and its colonies. And another version of the conflict. Is that the civilization would meet another civilization. And that thing causes star wars. But if the civilization is reaching the third step of the Kardashev scale. The origin of it turns meanless. If the civilization reaches the galactic scale. It would turn immortal. 

Of course, the end of the universe would put a limit on that race. But when the civilization will conquer the entire galaxy there is a small step to expeditions to other galaxies. The first steps are difficult. But this day science fiction is the routine of tomorrow. Technical advancing turns many things that were stories and theories yesterday practice of tomorrow. 

https://en.wikipedia.org/wiki/Kardashev_scale