How common are planets like the Earth around other stars? This is a question humanity has been asking since the dawn of civilization, ultimately feeding into the question as to whether we are alone in the Universe? Astronomers are on a quest to calculate "eta-Earth", the fraction of stars hosting Earth-like planets. Thanks to NASA's Kepler Mission, we have recently begun to answer this question. Prof Kipping gives a quick run down of the latest estimates. ::More about this Video:: ► NASA's Kepler Mission homepage: https://kepler.nasa.gov ► Foreman-Mackey et al. (2014), "Exoplanet population inference and the abundance of Earth analogs from noisy, incomplete catalogs": http://arxiv.org/abs/1406.3020 ► Dressing & Charbonneau (2015), "The Occurrence of Potentially Habitable Planets Orbiting M Dwarfs Estimated from the Full Kepler Dataset and an Empirical Measurement of the Detection Sensitivity": http://arxiv.org/abs/1501.01623 ► Outro music by Taylor Davis: https://www.youtube.com/watch?v=dl9kI1yQKZk ::Playlists For Channel:: Latest Cool Worlds Videos ► http://bit.ly/NewCoolWorlds Cool Worlds Research ► http://bit.ly/CoolWorldsResearch Guest Videos ► http://bit.ly/CoolWorldsGuests Q&A Videos ► http://bit.ly/CoolWorldsQA Science of TV/Film ► http://bit.ly/ScienceMovies ::Follow us:: SUBSCRIBE to the channel http://bit.ly/CoolWorldsSubscribe Cool Worlds Lab http://coolworlds.astro.columbia.edu Twitter https://twitter.com/david_kipping Instagram https://www.instagram.com/cool.worlds THANKS FOR WATCHING!!