What are the conditions for a planet suitable for immigration?

Immigration to a celestial body suitable for long-term human habitation needs to meet the following conditions:

first

It should be protected by the atmosphere. If the atmosphere of exoplanets is too dense or too thin, the cardiopulmonary function of human beings will be unbearable. Atmospheric composition is also important. The main components of the earth's atmosphere are oxygen and nitrogen, and they must meet a certain proportion. Too much oxygen will lead to drunkenness, and too low oxygen will lead to hypoxia. The ozone layer is also indispensable. Without it, the probability of human skin cancer will greatly increase.

then

There should be liquid water and a suitable temperature. Water is the source of life. According to the experience of the earth, life cannot exist without water. However, the existing means cannot confirm whether there is liquid water on exoplanets. We can only estimate the temperature on the planet according to the distance between the exoplanet and the star, and infer whether liquid water is allowed according to the temperature range.

once again

Livable exoplanets must have rocky surfaces so that humans can continue to live on land; Such a planet should have a perfect magnetic field to shield high-energy charged particles from stars and interstellar space; Planets must evolve to middle age, and the internal energy release is relatively mild, so that there will be no severe earthquakes, tsunamis and volcanic eruptions.

finally

The planetary system where exoplanets are located has evolved to the later stage, and a large number of small celestial debris are accreted by large planets, and the interplanetary space is gradually clear, and the probability of being hit by small celestial bodies is greatly reduced; The energy release of the star is relatively stable, otherwise, in the face of the super charged particle storm erupted by the star, human beings can only sit still.