Maybe you think one Earth is enough. Butwhat if there were billions? Researchers make a new estimate that the number ofEarth-like planets in our Milky Way galaxy can reach as high as 6billion.
Astronomers at the University of BritishColumbia (UBC) analyzed data from NASA’s Kepler mission toreach a stunning conclusion. The information on 200,000 stars was gathered bythe Keplerplanet-hunting spacecraft from 2009 to 2018.
The criteria used by the scientists forselecting such a planet maintained it had to be rocky, about the same size asEarth, and orbiting a star like our Sun. This planet also had to be in thehabitable zone of its star, where the conditions would be just right topotentially allow for water and life.
UBC researcher Michelle Kunimoto,who co-authored the new study, and previously discovered 17 new planets(“exoplanets”) outside our Solar System, said their calculations “place an upper limit of 0.18Earth-like planets per G-type star.” In other words, that’s about 5 planets perSun.
The study’s co-author UBC astronomer JaymieMatthews put this from another perspective, explaining that “Our MilkyWay has as many as 400 billion stars, with seven percent of them being G-type.That means less than six billion stars may have Earth-like planets in ourGalaxy.”
To conduct the study, Kunimoto utilized atechnique known as ‘forward modeling,’ which allowed her toovercome the issue that Earth-like planets are hard to spot on account of beingsmall and orbiting far from their star.
“I started by simulating thefull population of exoplanets around the stars Kepler searched,” expounded theresearcher in UBC’s press release. “I marked each planet as ‘detected’ or‘missed’ depending on how likely it was my planet search algorithm would havefound them. Then, I compared the detected planets to my actual catalogue ofplanets. If the simulation produced a close match, then the initial populationwas likely a good representation of the actual population of planets orbitingthose stars.”
While the scientists came up with animpressive number of possible Earths, this likely doesn’t mean that’s how manysuch planets there are and if they would have a life like ours. But this newestimate definitely expands the possibility that similar planets are out there.
Check out the new study in The Astronomical Journal.
