Is it possible to build a habitable artificial planet?
Let's imagine that one day in the distant future, our descendants conclude that life on our planet, for whatever reason, is no longer possible. Because of that it is necessary for mankind to focus on seeking another exoplanet in which our species could continue its existence. The first problem we would encounter, would be the great distance of a habitable planet outside the Solar System, which would make it impossible to easily accommodate especially the delivery of necessary resources. But what if, instead of searching for another habitable planet, our descendants decide to stay in the solar system and build an artificial planet? The questions are related to what kind of technology we would need, from where we could drag over a large quantity of raw materials and how much time would it take to make such an idea work? These and similar issues of realization of this idea are dealt with the mini documentary web series "What If".
The planets, whether they habitable or not, were created from the remnants of the formation of a new star. These dust-sized particle residues, not larger than diameter of human hair, collide and merged into larger formations which stayed together due to influence of the force of gravity, in order to finally, for tens of millions of years, form a planet. It is clear that our civilization, for the time being, is unable to create an artificial planet by accelerating the natural process, but we might be able to make an approximate replica of the planet that would meet the existing conditions: made by solid material, with breatable atmosphere, favorable temperature, gravity and stable orbit around the Sun. However, the question is how to reach a large amount of stone that would serve to form a kind of small replica of the Earth. Current considerations range from capturing asteroids and meteors or even to changing the orbits of existing natural satellites of some of the solar system's planets. However, it is clear that such ventures are almost unmanageable because mankind would need more than a hundred years of enormous engagement of the workforce and resources in order to bring this idea out. Even we can create an artificial a rocky planet, the problem would be to form an atmosphere that would suit us, and then its terraforming. Therefore, it might be easier to reconstruct the atmosphere of some of the existing planets of the Solar System that are in a habitable zone than to build an artificial Earth.