When can humans migrate to other planets?

Humans cannot migrate to other planets;

There are several points:

1) time

As far as going to Mars is concerned, if you can't even go to Mars, let alone other planets with worse conditions. If it takes at least 250 days to fly from the earth to the nearest orbit of Mars, then it will take two years to reach it (because the nearest orbit to the earth is once every two years), and it will take at least three years to return, then it will be difficult to solve the problem of food and shelter for astronauts in these three years. Also, transporting development tools from the earth requires a lot of resources. Unless a transfer station or base has been established on the moon and a nuclear-powered engine has been developed, it is impossible to realize interstellar migration.

2) Resources

Imagine how many resources are consumed. If you want to take 2-3 people to the moon and live on it, you should at least launch 200-300 tons of equipment or materials to the moon, but you should know that the earth in distance to the moon is only about 380,000 kilometers. It only takes two minutes to run back and forth. A few seconds. The nearest distance from Mars to the Earth is about 55 million kilometers, which is many times farther than the moon. It is unthinkable to transport hundreds of tons of things to Mars 55 million kilometers away. It is also necessary to consider how those hundreds of tons of things will not be burned into scrap iron when passing through the Martian atmosphere, and how to achieve a soft landing for such heavy things. Otherwise, spending so much money is just to build a "meteor" on Mars, and it takes so much manpower and material resources to send several people, let alone interstellar immigration. It will not be realized in 200 years (except for special reasons, such as another cold war, which usually makes science and technology advance by leaps and bounds).

3) Technology

I'm not kidding. In the next 30 years, space technology will not be able to send people to Mars, let alone immigrate. There are only a few problems in the development of technology: the source of power, the life support system that can run for a long time, the influence of high-energy radiation on human body, and the threat of meteorites to spacecraft.

4) Psychology

What if I have to stay in a small room for more than three years? Normal people can't stand it for a few days. Even if an astronaut has a super psychological quality, he is still human. If a certain mental illness is not treated, the consequences can be imagined.

So, not surprisingly, there should be no possibility of interstellar migration in the last 120 years.