NASA announces discovery of seven Earth-like exoplanets

For the first time ever, astronomers have discovered seven Earth-size planets orbiting a nearby star — and these new worlds could hold life.

This cluster of planets is less than 40 light-years away in the constellation Aquarius, according to NASA and the Belgian-led research team who announced the discovery on Wednesday.

The planets circle tightly around a dim dwarf star called Trappist-1, barely the size of Jupiter. Three are in the so-called habitable zone, where liquid water and, possibly life, might exist. The others are right on the doorstep.

TRT World spoke to Gary Blackwood, Program Manager at NASA, on the significance of the discovery.

Scientists said they need to study the atmospheres before determining whether these rocky, terrestrial planets could support some sort of life. But it already shows just how many Earth-size planets could be out there — especially in a star's sweet spot, ripe for extraterrestrial life.

The takeaway from all this is, "we've made a crucial step toward finding if there is life out there," said the University of Cambridge's Amaury Triaud, one of the researchers. The potential for more Earth-size planets in our Milky Way galaxy is mind-boggling.

"There are 200 billion stars in our galaxy," said co-author Emmanuel Jehin of the University of Liege. So do an account. You multiply this by 10, and you have the number of Earth-size planets in the galaxy — which is a lot."

Last spring, the University of Liege's Michael Gillon and his team reported finding three planets around Trappist-1. Now the count is up to seven, and Gillon said there could be more. Their latest findings appear in the journal Nature.

While faint, the Trappist-1 star is close by cosmic standards, allowing astronomers to study the atmospheres of its seven temperate planets. All seven look to be solid like Earth — mostly rocky and possibly icy, too.

They all appear to be tidally locked, which means the same side continually faces the star, just like the same side of our moon always faces us. Life could still exist in these places, the researchers explained.

"Here, if life managed to thrive and releases gases similar to that that we have on Earth, then we will know," Triaud said.

Chemical analyses should indicate life with perhaps 99 percent confidence, Gillon noted. But he added, "We will never be completely sure" without going there.