Our Universe, home for billions of galaxies, stars and trillions of habitable planets. Which means there are lots of opportunities for life to exist. But one question still remains unanswered by many astronomers, Why haven't we found an alien life civilization?. This is The Fermi Paradox.
If there are really extraterrestrial civilizations existing in other galaxies, there is still no chance of knowing it. As our universe expands, the distance between galaxies also expands. There is absolutely no way of traveling from one galaxy to another. Even if there is newly develop fast rockets, it would still take billions of years to reach the closest galaxy. So basically the focus should be on the Milky Way Galaxy, home for 400 billion stars.
Astronomers reported that there could be as many as 40 billion Earth-sized planets orbiting in the Goldilocks zone (habitable zones) of Sun-like stars and red dwarfs in the Milky Way, 11 billion of which may be orbiting Sun-like stars. The Milky Way is about 13 billion years old, about 1 to 2 billion years the first habitable planet was born. The earth has lived for an estimate of 4 billion years meaning there are chances for life to develop on other planets in the past. If there is an advance civilization in the milky way, through the advancement of technology we could have noticed it by now.
There are 3 categories to identify the type of Civilization (Kardashev Scale): Type I, Type II and Type III Civilization. A Type I Civilization can harness all the energy from its home planet and by all means, it can even control all its planet natural forces including volcano's, weather and earthquakes. A Type II Civilization is capable of harnessing all of the energy of its home star. This can be made possible with a concept of the Dyson Sphere ( A giant structure surrounding the star in order to harness its energy). Lastly, a Type III Civilization is capable of controlling and harnessing the energy of its home galaxy.
|Different Types of Civilizations|
According to Michio Kaku (Theoretical Physicist), our Civilization is currently at 0.73 on the scale of Type 0 to Type I Civilization and in next 100 years, we could reach a Type I Civilization-scale. Through the technology we have right now and the advancement of our civilization we've been harnessing 15 terawatts of energy from our planet. To reach the scale of Type I, we need to harness all the energy our home star is providing us that's about 1.74 x 10^17 watts.
The Great Filters that enables life to exist
Over the years, we have been developing and building different types of technology. Through this, the advancement of our civilization has been fast evolving, but every advancement has its own certain point.
This applies to the concept of Great Filters, a filter represents a barrier that is really hard for life to overcome. This includes the material structure, chemical composition, and orbital place of a planet or Before, the Universe is way more hostile and only recent things have cooled down to make complex life possible.
|The Great Filter From: www.atomicles.com|
Probably before, there is an Advance Extraterrestrial Civilization where its own technology is the main reason for the extinction of their kind. There are also possibilities of an ancient Type III Civilization that monitors the Universe, and once a Civilization is advanced enough, it gets eliminated or maybe we are the first, if not the first Civilization in the entire Universe. Many theories had been proposed why haven't we found an Extraterrestrial Civilization, some of which may be the answer to our question, others are not.
But one thing is for sure, that life in the Universe is possible and we are the living proof. Probably, if we visit other planets we might discover some form of life or even a Civilization. let's just hope that other Civilization is not hostile to visiting Civilizations.