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This artist’s impression shows a sunset seen from the super-Earth Gliese 667 Cc. The brightest star in the sky is the red dwarf Gliese 667 C, which is part of a triple star system. The other two more distant stars, Gliese 667 A and B appear in the sky to the right. Astronomers have estimated that there are tens of billions of such rocky worlds orbiting faint red dwarf stars in the Milky Way alone. Caption and image courtesy of the ESO/L. Calçada

Right now, Gliese 667 Cc is all the rage.

We talked about the exoplanet back in February when scientists announced that the super-Earth could be ripe enough for life. Gliese 667 Cc, which has a similar mass to Earth, is located in a triple star system in the constellation of Scorpius.

It is said to be within the habitable zone – an area far enough away from the sun where it isn’t too hot or too cold. Otherwise known as the “Goldilocks” zone, the area is a pretty good breeding ground for microbial life as liquid water could exist.

“It´s the Holy Grail of exoplanet research to find a planet orbiting around a star at the right distance so it´s not too close where it would lose all its water and not too far where it would freeze,” Steven Vogt, an astronomer from the University of California, said in this article. “It´s right there in the habitable zone – there´s no question or discussion about it. It is not on the edge. It is right in there.”

Right now, according to the Planetary Habitability Laboratory (PHL), there are only four exoplanets that are potentially habitable. Those planets include HD 85512, Gliese 581 d, Kepler-22 b, and Gliese 667 cc.

This image shows to scale the only four potential habitable exoplanets so far, HD 85512 b, Gliese 581 d, Kepler-22 b, and Gliese 667C c compared with Earth and Mars using the Earth Similarity Index, or ESI (number below the names). This number is a measure of Earth-likeness where Earth is the standard of comparison with an ESI value equal to one. Exoplanets with values above 0.8 can be considered Earth-like planets but those with values down to about 0.7 might still be habitable by microbial life. HD 85512 b, Gliese 581 d, and Kepler-22 b are shown here with dense atmospheres covered with water clouds. Gliese 581 d and Gliese 667C c look redder because they orbit red dwarf stars.

We’re sure more planets will make that list because the discoveries seem to be occurring at a much more rapid rate. There are billions and billions of planets out there. And, let’s not forget about the moons. From the 763 detected exoplanets – or planets outside of our solar system –  there are probably around 30 moons that could host life, according to the PHL.

Read more about planets, and the habitable zone, here.