After observing thousands of extrasolar planets discovered by the Kepler Space Telescope, researchers found that there are a large number of planets in the Milky Way, and there are planets around almost every star
The conclusion that there are two to six planets in the star system is calculated based on the Titius-Bodder rule more than 200 years ago, and is not a result of actual measurement.
 There are two to six planets in many star systems, of which about one third of the planets is in the habitable zone, and the temperature of the planet's surface is suitable for the existence of liquid water, which may mean that there are habitable planets almost everywhere in the Milky Way