Kepler Discovers First Earth-Sized Exoplanet Orbiting In The Habitable Zone
In a live teleconference, a NASA team today announced that the Kepler Space telescope has discovered the first Earth-sized exoplanet that orbits within its host star's habitable zone. Named Kepler-186f, this exciting new exoplanet discovery is of a similar size and potentially of a similar rocky make-up as our very own planet, Earth and most importantly, it orbits at a distance from its host star that would allow for temperatures conducive to the presence of liquid water.
The discovery of Kepler-186f is a landmark achievement in the hunt for potentially habitable exoplanets as, until now, the only exoplanets to be discovered within the habitable zone of their parent star have been at least 40% larger than Earth. These larger planets are thought to be too big to have a rocky composition, which means they would not be suitable for life as we know it. Kepler-186f, however is close enough to Earth's size to give scientists confidence that it may well be rocky in nature.
The only life in the galaxy that we have witnessed exists here, on Earth. Therefore, our best hope of finding life on another planet lies in discovering an exoplanet that displays similar characteristics to our own planet. With its similar size and ideal orbit distance, Kepler-186f is now officially the most Earth-like planet ever to be discovered. But it wasn't just Kepler-186f's size and orbit that had the NASA team so excited...
Kepler-186f's host star is what is known as a Red Dwarf star. These small and relatively dim stars are thought to be the most abundant in our galaxy, with around 80% of all stars thought to be Red Dwarfs. Discovering a planet with such Earth-like conditions orbiting a star as common as a Red Dwarf greatly improves the chances that there are more of them out there.
As exciting as this discovery is, it also comes with a warning of calm from the team.
"Being in the habitable zone does not mean we know this planet is habitable," said research scientist Thomas Barclay. "The temperature on this planet is strongly dependent on what kind of atmosphere the planet has. Kepler-186f can be thought of as an Earth-cousin rather than an Earth-twin. It has many properties that resemble Earth."
So while this is indeed a landmark discovery, and no doubt cause for great cheer, researchers are still looking for the perfect storm of an Earth-sized planet that orbits within the habitable zone of a star that is similar to our Sun. But, at the rate that Kepler is hauling in these discoveries, that seems to be more a case of 'when', not 'if'.
For more information on the exciting discovery of Kepler-186f, visit the official NASA release at the link below.