Researchers at the University of British Columbia (UBC) have made a new estimate of the potential number of Earth-like habitable planets in the Milky Way, resulting in a figure of 6 billion,media reported. This estimate is based on the number of G-stars in the Milky Way, which are similar to the sun of the galaxy where Earth is located. For a planet to be habitable, it must be in the “habitable zone” of its star — where it can neither be too hot nor too cold.
The study was carried out by co-authors, UBC researchers Michelle Kunimoto and Jaymie Matthews, and was recently published in The Journal of The Planet. The team is particularly concerned about the Milky Way, which they estimate has as many as 400 billion stars, but only 7 percent of them are sun-like G-stars.
Many of these stars have planets, but many of them are uninhabitable because temperatures are too high or too low. However, when a planet is in the habitable zone of its star, it is likely to have liquid water and a climate that could support the existence of life — these are called exoplanets.
According to Kunimoto, there may be as many as 0.18 exoplanets per G-star, equivalent to 6 billion Earth-like objects. It is understood that this result is based on a method known as positive modeling, Kunimoto said:
“I first simulated the total number of exoplanets around the stars that Kepler searched. Based on the possibility of finding them based on my planet search algorithm, I marked each planet as ‘detected’ or ‘missed’. Then I compare the detected planets with my real catalog. If the simulation results are very close, the initial number of planets is likely to represent the actual number of planets orbiting these stars. “