NASA launched the Kepler telescope in 2009. It’s mission is to discover Earth-size planets orbiting other stars. Kepler is part of NASA’s Discovery Program. The initial planned lifetime was 3.5 years. Kepler found 2,335 confirmed planets. That number includes about 50 worlds like Earth.
An Earth-size world orbits its host star in a NASA illustration
The Kepler team found that planets which are about 1.75 times the size of Earth and smaller tend to be rocky, while those two to 3.5 times the size of Earth become gas-shrouded worlds like Neptune. This is the eighth update of the Kepler planet catalogue and the most thorough survey of the space telescope’s data. However, Kepler is incapable of determining whether an exoplanet bears an atmosphere or liquid water. Kepler’s original mission ended in 2013. Now, it’s working using pressure from light particles from the sun to stay oriented. NASA estimates the telescope has enough fuel to remain active into 2018. Later, NASA will launch launch the Transiting Exoplanet Survey Satellite and the James Webb Space Telescope, which is designed to detect atmospheres on other planets.