Feasibility analysis of interstellar travel

If it can be extended to the whole universe, why worry about too many people on earth? Early Europe solved the population problem by sending surplus population to the New World. Why can't we continue this process? Our space program has pointed out the direction. This possibility is often raised in public meetings. 1958, four years after the establishment of NASA, the guardian of Congress, namely the Science and Space Committee, supported space immigration as the final solution to the "population explosion" problem.

How many habitable planets are there? Are these planets really suitable for us earthlings to live in? At the beginning of the 20th century, some people thought that Mars and Venus might be places where human beings lived. But soon after the establishment of NASA, it was an indisputable fact that other planets around the sun were not suitable for our life. We know that people on the surface of Venus must live at a temperature high enough to melt lead. He breathes air with carbon dioxide content of 96% and works at atmospheric pressure equivalent to the water pressure below our ocean surface 1/2 miles. It is speculated that Venus suffered a devastating "greenhouse effect". As for Mars, a frequent visitor in science fiction, living on this red planet is like living at twice the height of Mount Everest. The air of Mars contains very little water, and its atmospheric pressure is only 1% of the atmospheric pressure at the earth's sea level. The temperature is below 0 degrees Fahrenheit no matter day or night. So, when we talk about the migration between celestial bodies, we are actually only thinking about the migration between stars, to other stars other than the sun-assuming they have their own planets. A further hypothesis is that some of these imaginary planets may be as suitable for life as the earth.