About 7% of the Milky Way’s 200 billion or so stars are stars like the Sun, so it is possible that these planets are Earth-like.
“This is the first time that all the pieces have been grouped together to provide a reliable measure of the number of potentially habitable planets in the galaxy,” said study co-author Geoff Coglin, an exoplanet researcher at SETI and the Mountain View Institute in California, in a statement.
“We’re getting one step closer on the long road to finding out if we’re alone in the universe,” added Coglin, who also runs the Kepler Office of Science, which is dedicated to analyzing data collected by NASA’s Kepler Planetary Hunting Space Telescope.
A large team led by Steve Bryson of NASA’s Ames Research Center in California examined the observations made by Kepler, who worked from 2009 to 2018, and was an incredibly prolific space probe, discovering more than 2,800 exoplanets so far, i.e. Nearly two-thirds of the planets of all known alien worlds.
Kepler’s tally continues to grow as researchers continue to scrutinize his huge data set. Thousands of Kepler “candidates” await scrutiny with further analysis and observations.
Bryson and colleagues also examined data on stellar properties from the ESA’s GAIA spacecraft, which accurately maps out one billion Milky Way stars.
The team used this information to estimate the occurrence rates of rocky planets in the habitable regions of sunlike stars.