Scientists have discovered a remarkable cluster of planets resembling the core of our solar system, but better; seven Earth-sized worlds, each potentially capable of hosting liquid water and therefore life, in orbit around a nearby star.
The discovery sets a record for both the most Earth-size planets and the most potentially habitable planets ever discovered around a single star.
The strange planetary system is quite compact, with all of these worlds orbiting their star closer than Mercury orbits the sun, according to a newly published report in Nature.
“If you were on the surface of one of these planets, you would see the other ones as we see the moon or a bit smaller,” says Michaël Gillon, an astronomer at the University of Liège in Belgium. “The view would be very impressive.”
The system’s existence suggests that Earth-size planets are much more plentiful than previously imagined.
And now, it is among the best “neighborhoods” to study for signs of life beyond Earth: The relative sizes of the planets and star, plus the system’s proximity, mean that plucking the signatures of living, breathing organisms from the planet’s atmospheres could be within reach.
“Those yawning over yet another discovery of habitable-zone planets may not fully appreciate that priorities are shifting and focusing,” says NASA’s Natalie Batalha. “Temperate, terrestrial-sized planets are relatively common in the galaxy. The name of the game now is to find those near enough for atmospheric characterization.”
Planet-hunters have recently been gathering more and more evidence that Earth-size planets are common in our galaxy, according to Ignas Snellen at the University of Leiden in the Netherlands, who wrote a commentary that accompanied the scientists’ announcement.
This new discovery, he notes, suggests such worlds are “even more common than previously thought.”