NASA launched the Kepler telescope in 2009 to stare out into space. In October, 2018, the telescope "retired." What did we learn from it and how did it work?Learn more about advertising on the HowStuffWorks podcasts at www.howstuffworks.com/advertisers.htmAnd to learn about your ad choices when listening to podcasts, visit https://www.howstuffworks.com/privacy.htm#ad-choices