Are there any habitable planets in the galaxy?

Life is certain. Even according to the model of the earth, scientists have calculated that there are millions of Earth-like planets in the Milky Way alone, so even if the birth of life is difficult, it is very likely that there will be life among them. And the life pattern of the earth is not necessarily unique. It is possible to give birth to life under conditions such as high pressure, high temperature and high radiation that are not conducive to life on earth.

Then the next question is why we humans have not found extraterrestrial life. From the point of view of our planet, we all know that technology is not developed enough. Then let's discuss it from the standpoint of alien life. There are three situations: the technological level of alien life is not as developed as ours; Equal to or slightly higher than our level; Far above us. Then the first two situations are obvious, we can't find them, and they are almost as natural as us and can't find us. That is, it is much higher than our alien life. They can visit the earth even when we can't imagine interstellar travel, so their development level is beyond our imagination. Then they don't need to contact us, just like some of our explorers will probably record and study new species when they discover them in the virgin forest, but they won't think about contacting and communicating with them. The communication object of human beings is to understand their own existence, and we will not explain the principle and purpose of computers to cats and dogs. Or in the eyes of advanced alien life, we are no different from cats and dogs.

I don't know how many people can accept this, but I'm afraid this is the reason why alien life seems to have been moving on the earth but has never let us know about it.