Callista may be a habitable planet that can accommodate 400 million people.

In the solar system, the only planets in the habitable zone are Earth, Venus and Mars. However, the environment of Venus is too harsh and it will be difficult for humans to live in the future.

The environment of Mars is better than that of Venus, but its environment is also difficult to live in. The magnetic field around Mars is weak, and solar winds often occur, making it difficult for organisms to survive. If you want to survive on Mars, , a colonial base must be built on Mars with an internal environment similar to that on Earth. There is no doubt that building such a base requires a lot of manpower, material and financial resources.

Scientists have discovered that Saturn’s moon Callisto is very similar to the Earth billions of years ago, and Callisto stores a large amount of basic materials needed for human survival. Scientists predict that Titan may be able to sustain about 400 million people. Titan is the largest satellite of Saturn and the second largest satellite in the solar system. Its diameter is 5,000 kilometers

Titan has a thick atmosphere, abundant water resources, and four seasons. , perhaps one day in the future, this will become the home of mankind.