Nicolaus Copernicus was the first to claim that, the sun stand in the middle of the solar system, and around the sun orbits planet Earth. Furthermore he claimed that Earth is an ordinary planet under specific conditions that led to the origin of life. This idea, 500 years ago, wasn’t warmly accepted.
The sun is a star producing effectively for over 5 billion years, nuclear energy in the process of turning hydrogen into helium, and will continue to do so until hydrogen will run out, then the sun will turn off. Shortly before that moment, the sun will expand 200 times her current size and swallow nearby planets including the earth. Before this dramatic end, humanity has long time for exploring the environment we live in.
If you ask yourself why life evolved in the solar system on planet Earth, the answer is, because of the mediocrity. Earth is a middle size planet in specified distance from the sun that allows the existence of liquid water, which led to the origin of life. The sun is a medium-sized star relative to over 500 billion other stars in the galaxy.Contrary to light star which don’t produce sufficient energy to allow life, heavier stars than the sun explode too early to allow the creation of life. So, the demand for life is a medium condition - neither too hot nor too cold. Our galaxy is a medium one, out of billions of galaxies in the universe that allowed vast production of stars and planets, including our solar system planets and sun.
So from where all this mediocrity has started? The idea for the beginning of the universe is described best by the big bang theory which confirmed each time by measurements and observations. The theory claims that the universe began 13.7 billion years ago, from a very hot area, containing only elementary particles. After the ‘initial expansion’ process that shaped our current universe, the first elements created were hydrogen and helium, which after billion years formed the first stars which produced the heavier elements, among them oxygen, nitrogen and carbon necessary for life.
The universe continues to expand until eventually stars will cease to be formed. The stars that exist will stop producing energy and then it will be impossible to sustain life. Not only that the universe is expanding, but it’s also accelerating his movement For the measuring of the accelerating movement of the universe three researchers won the Nobel prize.
The Earth, the Sun and our galaxy are all relative medium size and were created from the big bang. The question we should ask is: whether the big bang is relative medium bang of a series of big bangs? If the answer is yes, that mean multiple universes each with different physics laws, exists parallel to each other. This idea derived from Copernicus who said there's nothing special on Earth, the sun and the galaxy. Idea of multiple universes also comes from theorists trying to explain the basic forces in nature. From developing models, a huge collection of solution is obtained, so for each solution there is an appropriate universe, but we still don’t know which solution fits our universe. In different universes, different physics laws are applied, and therefore we can’t measure physical phenomena with the tools we have developed in our universe. Furthermore each universe has its own individual expanding space and time field.
Our universe as Earth, the sun and our galaxy is also Medium universe, that hasn’t spread to fast nor collapsed too quickly, to give enough time for the creation of life. The obvious conclusion, in the search for other life forms we need to search the mediocrity that lead for them.