Earth and Kepler-452b. Illustration comparing Earth (left), the exoplanet Kepler-452b (right), and their G2-type parent stars (centre). The planets are in their star's habitable zone and can support liquid water and life. Kepler-452b (around 20,800 kilometres across) is 63 percent larger than Earth (12,742 kilometres across) and orbits every 385 days compared to Earth's 365 days. The star Kepler-452 is 1.5 billion years older than the Sun, and hence brighter and hotter. This planet, 1400 light years distant in the constellation of Cygnus, is one of many discovered by NASA's Kepler space observatory, launched in 2009. The discovery was announced on 23 July 2015.