Astrophysicist and TED Fellow Sarah Rugheimer searches for aliens -- but not the cartoony green kind. She's looking for extraterrestrial microbes by studying how these single-celled organisms emit gases, which could reveal evidence of them throughout the cosmos. Wondering if we're really alone in the universe, Rugheimer identifies two big hurdles to confirming life on another world and offers insight into what finding it might mean for us.

Sarah Rugheimer: The search for microscopic aliens

The search for microscopic aliens

Exploring alien worlds, the real quest lies in detecting microbial life, not green beings, challenging our telescopes and interpretations.

Oxygen, methane, and nitrous oxide in Earth's atmosphere, primarily from microbes, could be the cosmic breadcrumbs to alien life.

Venus' phosphine discovery tantalizes and confounds, blurring lines between life and geophysical processes in our search for the cosmic kin.

*The Great Courses: Searching for Extraterrestrial Life with Sarah Rugheimer*

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