LOS ANGELES — Our Milky Way is home to at least 17 billion planets that are similar in size to Earth, a new estimate suggests. That’s more than two Earth-size planets for every person on the globe.
Just how many are located in the sweet spot where water could exist is “simply too early to call,” said Francois Fressin of the Harvard-Smithsonian Center for Astrophysics, who presented his work at an astronomy meeting Monday.
Fressin and his team came up with their figure by conducting a fresh analysis of data collected by NASA’s Kepler spacecraft, which was launched in 2009 to track down other Earths. They estimated at least one in six stars in the galaxy hosts a planet the size of ours, translating to at least 17 billion Earth-size worlds.
Fressin said it’s clear that rocky planets abound outside the solar system.
“If you look up on a starry night, each star you’re looking at — almost each one of them — has a planetary system,” Fressin said.
