7 Earth-size worlds found orbiting star; System 40 light-years away could hold life
Published 8:54 am Thursday, February 23, 2017
CAPE CANAVERAL, Fla. — For the first time, astronomers have discovered seven Earth-size planets orbiting a single 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 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, the area around a star where water and, possibly life, might exist. The others are right on the doorstep.
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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 more planets like this, the greater the potential of finding one that’s truly habitable. Until now, only two or three Earth-size planets had been spotted around a star. A rocky Earth-sized world inside a star’s habitable zone is considered the best candidate for finding evidence of life.
“We’ve made a crucial step toward findiang 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. The history of planet-searching shows “when there’s one, there’s more,” said Massachusetts Institute of Technology astrophysicist Sara Seager.
“With this amazing system, we know that there must be many more potentially life-bearing worlds out there just waiting to be found,” she said.
NASA’s Thomas Zurbuchen, associate administrator for the science mission, said the discovery “gives us a hint that finding a second Earth is not just a matter of if, but when,” and addresses the age-old question of “Are we alone out there?”
“We’re making a step forward with this, a leap forward in fact, toward answering that question,” Zurbuchen said at a news conference.
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.