TRAPPIST-1 is an amazing system discovered last year featuring seven roughly Earth-sized planets all transiting their diminutive parent star. Could there be an eighth? If there is, in this video Prof Kipping argues that it should be possible to precisely predict what the orbital period of such a planet would be. Right or wrong, this prediction provides a falsifiable hypothesis to test our understanding of the rules governing planetary system architectures. ► Kipping (2018), "Predicting the Orbit of TRAPPIST-1i", AAS research note: https://arxiv.org/abs/1807.10835 ► Gillon et al. (2017), "Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1", Nature: https://arxiv.org/abs/1703.01424 ► Luger et al. (2017), "A seven-planet resonant chain in TRAPPIST-1": https://arxiv.org/abs/1703.04166 ► Sonification of the TRAPPIST-1 system by System-Sounds.com: https://www.youtube.com/watch?v=WS5UxLHbUKc&t=4s ► Cool Worlds video by Chris Lam, "A Machine That Can Predict Exoplanets": https://youtu.be/6xxt9ke8uYo ► Cool Worlds video by Moiya McTier, "TRAPPIST-1: Multiple Chances for Life!": https://youtu.be/16mROb2O2rA ► Columbia University Department of Astronomy: http://www.astro.columbia.edu ► Cool Worlds Lab website: http://coolworlds.astro.columbia.edu ::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 Tabby's Star ► http://bit.ly/TabbysStar 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!!