... "Kepler already told us there were billions of planets, but now we know a good chunk of those planets might be rocky and habitable," said astronomer Steve Bryson of NASA's Ames Research Center. I note in the report on this possible, habitable Earth 2.0, "Kepler-1649c is just 1.06 times the size of Earth and gets 75% of the stellar energy influx that our planet gets from the sun. That comes to 200 quintillion, or 200,000,000,000,000,000,000. To make a calculation of how many habitable planets there might be then, we can take the estimate of 2.5% from the total number of planets (20 sextillion). Planets in a red dwarf's comparatively narrow habitable zone, which is very close to the star, are exposed to extreme levels of X-ray and ultraviolet (UV) radiation, which can be up to hundreds of thousands of times more intense than what Earth receives from the Sun. A newly discovered, roughly Earth-sized planet orbiting our nearest neighboring star might be habitable. It is more difficult than you might think to define what makes a planet habitable, as astrophysicist Christopher Watson explains. Our galaxy is filled with potentially habitable planets -- at least 300 million of them, according to NASA. MICHELLE STARR. The US space agency's Kepler Space Telescope spent nine years on a planet … 30 OCTOBER 2020 . There Could Be at Least 300 Million Potentially Habitable Worlds in The Milky Way . After poring over data from a nine-year mission, NASA says there are at least 300 million potentially habitable planets in the Milky Way. The Habitable Planet was designed for teachers, educators, and adult learners with a science background who want to learn more about current issues in environmental science. College or graduate students, advanced high school students, or even professional scientists may also find this course useful. Conclusion: habitable planets in numbers.