Photo: Artist’s conception of Kepler telescope observing planets transiting a distant star (NASA Ames/W Stenzel).
Researchers have estimated that the number of planets that are similar to Earth in our own galaxy could be as many as 6 billion.
Data from NASA's Kepler mission were analysed by astronomers at the University of British Columbia (UBC) to reach the conclusion. The information on 200,000 stars was gathered by the Kepler planet-hunting spacecraft between 2009 and 2018.
Among the criteria set by the scientists for selecting candidate planets were, rockyness, its size being similar to Earth and orbiting a star similar to our Sun. The latter criterion also involved the planet being within the habitable zone of its star, allowing for the development of life.
Michelle Kunimoto, UBC researcher and co-author of the study, who had previously discovered 17 planets outside our solar system, said that their calculations:
"place an upper limit of 0.18 Earth-like planets per G-type star."
Meaning that there are roughly about 5 Earth-like planets per candidate Sun.
Jaymie Matthews, UBC astronomer who also co-authored the study, explained:
"Our Milky Way has as many as 400 billion stars, with seven per cent of them being G-type. That means less than six billion stars may have Earth-like planets in our Galaxy."
In order to conduct the study, Kunimoto used a technique known as, 'forward modelling', which allows to spot Earth-like planets that are too small and orbiting far from their star.
She said in a press release:
"I started by simulating the full population of exoplanets around the stars Kepler searched. I marked each planet as 'detected' or 'missed' depending on how likely it was my planet search algorithm would have found them. Then, I compared the detected planets to my actual catalogue of planets. If the simulation produced a close match, then the initial population was likely a good representation of the actual population of planets orbiting those stars."
While the number of possible Earth-like planets that the scientists came up with is impressive, this does not necessarily mean that they are actually habituated, or that the life that might exist there is similar to ours. But this new research definitely affirms the possibility that such planets do exist.
[h/t: Big Think]
COMMENTS