Astronomer Michelle Kunimoto from the University of British Columbia (Canada) found out that up to six billion planets resembling the Earth and potentially suitable for life can be in the Milky Way. This was reported in an article published in The Astronomical Journal.
According to Kunimoto, one star of the spectral class G (yellow stars like the Sun) has 0.18 Earth-like planets. The proportion of such stars is seven percent of the total number of stars in the Milky Way, of which only about 100-400 billion.
To calculate the probable number of planets similar to Earth, Kunimoto and her team of astronomers used the direct simulation of exoplanets from 200 thousand stars studied by the Kepler space telescope.
The algorithm did not always correctly predict whether a particular star has exoplanets, however, a comparison of the catalog generated by the model with the actual catalog of planets gave the most probable estimate of the number of planets in the Milky Way.
Based on this number, experts determined the fraction of earth-like planets whose mass lies in the range 0.75-1.5 of the Earth’s mass, orbiting a G-star at a distance of 0.99-1.7 astronomical units (an astronomical unit is approximately equal to the average distance from Sun to Earth).
The maximum number reaches six billion, but the real number is much less. Also, this does not guarantee the existence of life on the planets, since in the solar system Mars meets the considered criteria.