What is the most suitable planet for human immigrants to live in?

Mars has many characteristics similar to that of the earth. It is 227.94 million kilometers away from the sun, about 1.5 times the distance between the sun and the earth. The angle between the rotation axis and the orbital plane is 24, which changes all the year round like the earth. It is less than half the rotation of the earth, that is, 24 hours, 37 minutes and 22.6 seconds. So the length of day and night of Mars and Earth is basically the same, but the period of revolution around the sun is almost equal to two years for Mars. Because Mars is far from the sun, its period of revolution is 687 days. Mars is about half the diameter of the earth; 1/6 smaller than the earth; The mass is only110 of the earth; The atmosphere of Mars is much thinner than that of the earth. Its main components are carbon dioxide, accounting for 95%, nitrogen accounting for 3%, and a very small amount of oxygen and water.

The average temperature of Mars is minus 23 degrees Celsius. Due to the thin and dry atmosphere of Mars, the temperature difference between day and night is very large, which is much larger than that on the earth. Due to the low surface temperature and low air pressure on Mars, carbon dioxide and water in the atmosphere are almost saturated. As long as the temperature drops slightly, carbon dioxide and water vapor will condense. There is little water in the atmosphere of Mars. Scientists estimate that if all the water ice on Mars melts into water, only an ocean with a depth of 10 meter can be formed on the surface of Mars. Compared with the vast ocean on the surface of our earth, the water on Mars is negligible.