According to new research using data from NASA’s retired planet-hunting mission, the Kepler space telescope, about half the stars similar in temperature to our Sun could have a rocky planet capable of supporting liquid water on its surface.
Our galaxy holds at least an estimated 300 million of these potentially habitable worlds, based on even the most conservative interpretation of the results in a new study to be published in The Astronomical Journal. Some of these exoplanets could even be our interstellar neighbors, with at least four potentially within 30 light-years of our Sun and the closest likely to be at most about 20 light-years from us. These are the minimum numbers of such planets based on the most conservative estimate that 7% of Sun-like stars host such worlds. However, at the average expected rate of 50%, there could be many more.
This research helps us understand the potential for these planets to have the elements to support life. This is an essential part of astrobiology, the study of life’s origins and future in our universe.
The study is authored by NASA scientists who worked on the Kepler mission alongside collaborators from around the world. NASA retired the space telescope in 2018 after it ran out of fuel. Nine years of the telescope’s observations revealed that there are billions of planets in our galaxy — more planets than stars.
«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 the lead author Steve Bryson, a researcher at NASA’s Ames Research Center in California’s Silicon Valley. «Though this result is far from a final value, and water on a planet’s surface is only one of many factors to support life, it’s extremely exciting that we calculated these worlds are this common with such high confidence and precision.»
For the purposes of calculating this occurrence rate, the team looked at exoplanets between a radius of 0.5 and 1.5 times that of Earth’s, narrowing in on planets that are most likely rocky. They also focused on stars similar to our Sun in age and temperature, plus or minus up to 1,500 degrees Fahrenheit.
Story Source: Materials provided by NASA. Original written by Frank Tavares, NASA’s Ames Research Center. Note: Content may be edited for style and length.