New observation by a Penn State researcher found the number of Earth-sized habitable planets is much greater than earlier thought, according to a Science Daily report.
Observations made by Ravi Kopparapu, a post-doctoral researcher in geosciences, shows the number of Earth-Sized habitable planets are at least three times more than our previous estimates.
"We now estimate that if we were to look at 10 of the nearest small stars we would find about four potentially habitable planets, give or take," Kopparapu said, noting there could more.
The hunt for the Earth-sized planets in the habitable zones of M-dwarfs have always been a subject of great focus, the shorter orbits helps scientists to cover more orbits and gather more information without spending much time than scientists could have on Sun-like stars. Since M-dwarfs are more commonly available comprising of nearly 70 percent of all the stars in our galaxy, it makes it possible for the scientists to observe them in more numbers.
Accoridng to Kopparapu latest observations, it has come to light that the existence of the nearest Earth-size habitable planet is about seven light years, which is nearly half of what was believed to be estimated earlier. He noted that just within 10 light years, there are about eight M-dwarfs which according to him may host about three Earth-size planets.
The study was a follow up on a previous study conducted by Harvard-Smithsonian Center for Astrophysics' researchers who analyzed 3,987 M-dwarf stars to calculate the number of Earth-sized planet candidates in M-dwarfs' habitable zones.
The study made use of data compiled by Jim Kasting, now an Evan Pugh Professor in Penn State's Department of Geosciences in 1993. However, in this new study Kopparapu found that NASA's Kepler satellite data didn't reflect the most recent estimates for determining whether planets fall within a habitable zone.
Kopparapu and his team modified and developed a model using the latest information on water and carbon dioxide absorption.
"I used our new habitable zone calculations and found that there are nearly three times as many Earth-sized planets in the habitable zones around these low mass stars as in previous estimates," Kopparapu said. "This means Earth-sized planets are more common than we thought, and that is a good sign for detecting extraterrestrial life."
