Overview: Astronaut Mike Massimino reveals the alien secrets of comets, strange visitors from deep space that might be responsible for life on Earth.
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First Air Date: Aug 22, 2017Last Air date: Sep 25, 2018Season: 2 SeasonEpisode: 23 EpisodeRuntime: 43 minutesQuality: HDIMDb: 7.80 / 10 by 5 usersPopularity: 3.336Language: English