Kepler-186f, the First Validated Earth-size Planet Orbiting a Distant Atar in the Habitable Zone (video) Gemini Observatory Share Print E-Mail Loading video... Caption This animation depicts Kepler-186f, the first validated Earth-size planet orbiting a distant star in the habitable zone -- a range of distances from a star where liquid water might pool on the surface of an orbiting planet. The discovery of Kepler-186f confirms that Earth-size planets exist in the habitable zone of other stars and signals a significant step closer to finding a world similar to Earth. Kepler-186f is less than ten percent larger than Earth in size, but its mass and composition are not known. Credit Credit: Sean Raymond. Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.