According to a new study, scientists believe that there could be as many as six billion Earth-like planets just in our Milky Way galaxy. Based on their calculations, researchers estimated that there could be 0.18 Earth-like planets for each G-type main sequence star (which are stars that are similar to our own sun).
Astronomer Jaymie Matthews from the University of British Columbia, Canada, and co-author of the study, explained this further, “Our Milky Way 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 our Galaxy.”
In order to qualify as Earth-like, the planet has to have a rocky surface, be approximately the same size as Earth (around 0.5 to 1.5 times the size), and be located in the habitable zone of their host star where it could possibly contain liquid water.
Unfortunately, finding Earth-like planets isn’t a fast job as it could take numerous years to identify them based on where they are located in proximity to their star and how long it takes them to complete a full orbit.
There have been several previous estimates in regards to how many Earth-like planets could be located in our galaxy alone. The numbers ranged from 0.02 Earth-like planets for each sun-like star to more than one per sun.
The researchers conducted computer simulations called “forward modeling” where they analyzed data obtained from approximately 200,000 stars that were studied by the Kepler Space Telescope.
The other co-author of the study, Michelle Kunimoto, explained this computer simulation technique in greater detail, “I started by simulating the full population of exoplanets around the stars Kepler searched,” adding, “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 catalog 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.”
Kepler detected over half of the exoplanets that have been found to date. So far, more than 4,000 exoplanets have been confirmed with thousands more candidates waiting for confirmation. This is incredible as the first ever exoplanet was discovered in the early 1990s. And with this new study where up to six billion Earth-like planets could potentially be found in our own galaxy, scientists will certainly be busy for the next little while analyzing planet data.
I wonder how many, if any, of the six billion Earth-like planets will have life... Perhaps one of the 36 intelligent civilizations mentioned in a new study that could potentially be living in our galaxy may be located on one of those planets.