Why must we search for other extraterrestrial civilizations?

At the beginning of this text, I must say that not all alien life forms are probably intelligent. Most of the alien life forms that we can imagine or predict are bacteria. There is a possibility. That some bacteria or viruses can survive interstellar travel. That means their genetic material remains in a condition that it can transfer into the cells of Earth organisms. 

A virus is a protein package. There is genetic material. And that thing can survive in the freezing cold of interstellar travel. The gamma- or X-ray bursts can destroy that genetic material. But otherwise. The space between stars is very stable. It freezes genetic material almost forever. 

There are no certain observations about the alien civilizations. So, we have no confirmed observations about those still hypothetical aliens. But when do we detect them? We don’t know. But. That can happen tomorrow, or it can happen after 1000 years. 

But then, to the intelligent lifeforms. Why should we continue the Search For Extraterrestrial Intelligence (SETI) program? Because there are billions of stars in our galaxy. And there are billions of galaxies in the universe. Somewhere there must be alien civilizations. And the SETI program ends in the day, when we see that civilization. 

Here I must say one thing. Even if SETI finds another civilization. That doesn’t mean that we make contact with that civilization. This is one of the things that people must realize. But. Confirming the existence of another civilization is very difficult. 

There are a couple of so-called breakthrough listen candidate signals. Those signals are. So-called Wow! and the Alpha Centauri signals. Those signals are unique, and we don’t know how long they lasted. We know only the part of those signals that the radio telescopes captured. And that is one of the things that we must realize. The thing is that those signals happened only once. Supporting the model that they were synthetic. 

If we think that the origin of those signals is in a natural source, that means they should repeat.  But. There is a possibility. that their origin was in the reactions as the Gamma-ray burst traveled through the plasma of some star’s flares. There is a possibility that a very rare natural effect causes those signals. But. As we know. The universe is a strange place. And. It's possible that the fast energy pulse travels through plasma fields. But as we know, we must only guess how long those signals lasted. And because there are no other similar signals, we must only guess whether they are synthetic or not. 

So, why have aliens not contacted us yet? The reason for that can be that they don’t detect us. Even if we send microwaves. And radio signals all around us, we must realize that. Those signals traveled for less than 200 years. 200 light-years is quite a short distance in the scale of the Universe. 

And when we look around us, and look at things like the closest stars, we can see that we are surrounded by young stars. Sirius is the brightest star in the northern sky. Sirius is a binary star system, and the brighter component of that system is only 230 million years old. Sirius B is a white dwarf. That was once a Sun-like star. Components of that star are formed in different places and at different times. And once in history, gravity locked those stars together. If Sirius B had some kind of planetary system, Sirius A would destroy it. 

Things like mature red dwarfs can also be more suitable harbours for life than we think. A red dwarf can exist as a star far longer than the Sun. If we think that the Sun will stay. As a yellow star for about 7-10 billion years. The red dwarf can exist as a star for about 11 trillion years. The young red dwarf has a hyperactive period. Just like other young stars. Then, after the hyperactive period, the red dwarf’s planets can turn into the harbours of life. That period starts later than in the Sun-type stars.  

But it takes longer. The fact is that most of the red dwarfs near our solar system are young. The age of Proxima Centauri is about the same as the Sun's. And Wolf 359 is about 0,1-1,9 Gyr( Gigayear(10^9, or Billions of years)). The third remarkable red dwarf, Barnard’s star, is about 10 Gyr. This can explain why there are no civilizations near us. The only star system that is the same age as our sun is the Alpha Centauri system. Those stars (Alpha Centauri A, B, and Proxima Centauri) are all about the same age as the Sun. 

Another thing is that. The alien civilization might not hear us. The universe is full of radio sources. But the thing is that. We don’t know what those aliens look like, how they communicate, or where they are. We don’t know anything about their culture. And we certainly hope that we detect them before they detect us. The third thing that we can hope for is that the alien civilization is not as destructive as we are. But. If we someday detect an intelligent civilization, we must carefully think. About our next step. We must realize that those aliens can be hostile. But when do we detect them? As I wrote many times. That can happen tomorrow or after 1000 years. 

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

https://en.wikipedia.org/wiki/Barnard%27s_Star

https://en.wikipedia.org/wiki/BLC1

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

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

https://en.wikipedia.org/wiki/Wolf_359

https://en.wikipedia.org/wiki/Wow!_signal

Researchers found a miniature black hole.

"Astronomers using Gaia data have just found a low-mass black hole orbiting a companion star. Credit: WANG Song" (Astronomy.com, Astronomers find a mini black hole)

Today the minimum mass of the black hole is about 2,2 times of the sun. But if the lighter object orbits a high-energy object that energy can transform almost any object in the universe into a black hole. 

"Astronomers have discovered a lightweight black hole that’s a bit of a cosmic conundrum. Hypothetically, black hole masses can range all the way from far less than a paperclip to at least tens of billions of times more than the Sun. But observations have revealed a strange scarcity of black holes between about two and five times the Sun’s mass. Right now, it’s unclear whether these mini black holes are just hard to detect or actually as rare as they seem to be." (Astronomy.com, Astronomers find a mini black hole)

"The newfound black hole could offer clues. It falls right in the middle of the gap, weighing in at about 3.6 solar masses. A team of scientists found it thanks to a bloated companion, a red giant star located about 5,800 light-years from Earth. Though the star is only about 2.7 times as massive as the Sun, it’s around 13 times larger and 100 times brighter. " (Astronomy.com, Astronomers find a mini black hole)

It's possible. That all low-mass black holes are not stable. That means they can vaporize very fast. And that can cause an effect that looks like a supernova, that comes from nowhere. 

Theoretically, a black hole's mass can be anything from an electron to the tens of billions of suns. That theory is almost proven. There are supermassive- medium-mass and stellar-mass black holes.  But the miniature-, or-low mass, and planet mass black holes are missing. The miniature black hole supports the black hole theory. 

Things, like low-mass black holes make things like superstring theory more suitable. In some models, elementary particles are whisk-shaped structures that superstrings are forming. And in some versions of that theory, those superstrings are a series of quantum-size black holes. Those quantum-size black holes are like pearls in necklaces. That thing explains the power of the annihilation reaction. 

The mini black hole is also introduced behind the mysterious gravity effect in our solar system. That makes some researchers believe that there is still an unknown planet lurking in the Kuiper belt. It's possible. Earth-size planets can turn into black holes if they travel through the black hole's relativistic jet. That thing can form the symmetrical energy impulse that presses the planet into the black hole. 

Another suspected place for the black hole is the star system of Epsilon Indi. That star travels very fast around the universe, and it is also a bright X-ray object. That thing makes some people believe, that there is some, maybe a grapefruit-size black hole near that star. 

https://www.astronomy.com/science/astronomers-find-a-mini-black-hole/