Is it possible for humans to migrate to other planets?

It should be said that after World War II, with the rapid development of space science and the first step out of space, many people have the idea of human beings moving to other planets in the future.

People who are not optimistic about the future of the earth may find another home in the universe, just like Europeans immigrated to the United States and Australia hundreds of years ago, and adventurous people cheered and boarded spaceships, just like sailors were looking forward to traveling to distant countries.

In the new settlements, various technologies are needed to make food, water, air and other necessities. Self-sufficiency in settlements is also very important. There is no earth "hospitality" in other parts of the solar system. So life in the settlement must be awkward at first. The first settlers needed some courage and skills to survive in difficult conditions. They will come from all over the world, and everyone's experience is completely different. Some people may want to have another social form because they are dissatisfied with the politics on the earth. Dissatisfaction with society is also one of the main reasons why people moved to the United States or Australia centuries ago.

Planets or satellites that choose to settle must have a solid surface, that is, Jupiter, Saturn, Uranus and Neptune cannot be taken into account, because they are all foggy planets and have no solid surface. In addition, the surface temperature of a planet or satellite should not be too high. Mercury's ground temperature is above 400℃, so in theory, humans can't make a home on it.

Also, gravity should not be too weak, otherwise people can't walk upright on the surface. The gravity of the moon is only 1/6 of the gravity of the earth, and the gravity on the selected planet or satellite cannot be lower than the gravity of the moon. As a result, many small satellites are not suitable for human habitation, just like asteroids or comets.