Discovery of Billions of Earth-Like Planets
According to one study, there may be as many as 6 billion Earth-like planets in our galaxy.
In the world, Earth is the only planet capable of supporting life. Scientists have been searching for exoplanets – worlds outside our planetary system – for years in order to determine the likelihood of life somewhere in the Milky Way. A world must be rocky, around the same size as Earth, and orbit Sun-like (G-type) stars to be called Earth-like. It must also orbit within the star’s habitable zones, or the altitude at which the earth is neither too hot nor too cold for life to survive.
What is the maximum number of Sun-like stars that can contain an Earth-like planet?
According to the UBC research team, every five G-type stars in the Milky Way may have an Earth-like exoplanet. Earth-like planets have previously been estimated to occur in quantities ranging from 0.02 potentially stable planets per G-type star to more than 1 per G-type star. Michelle Kunimoto, co-author and UBC scholar, said, “My estimates put an upper limit of 0.18 Earth-like planets per G-type star.” She had previously found 17 extraterrestrial worlds.
Is there anybody out there?
Over 4,100 exoplanets have been discovered that are the right size and orbital distance from their star to sustain liquid water and possibly life. Until now, it seems like a fair guess. Estimates and measurements by astronomers at Canada’s University of British Columbia (UBC) who used data from NASA’s Kepler Mission suggest that there are many more Earth-like planets in our galaxy than commonly thought, according to recent research reported in The Astronomical Journal. In reality, billions of Earth-like planets surround G-type stars in the Milky Way. Only planets orbiting these stars were included in the analysis.
“There are up to 400 billion stars in our Milky Way galaxy, with seven pea-sized ones.
“Knowing how frequent various kinds of planets are around different stars will have valuable restrictions on planet creation and evolution hypotheses, as well as help refine potential exoplanet-hunting missions,” Kunimoto concludes.
Is someone else out there? This watershed moment in planet hunting will one day help to address this age-old query.
For more information on this study, see Kepler Space Telescope Reveals as Many as Six Billion Earth-Like Planets in Our Galaxy.