Prof. Carl Sagan
@ProfCarlSagan • 70,413 subscribers
Tribute to the man who taught us skepticism, critical thinking, and a sense of wonder for the natural world.
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American chemist Wallace Carothers discovered nylon in 1935 while leading research at DuPont. His goal was to create synthetic "superpolymers" with protein-like structures to emulate or replace natural silk. During his 1976 Christmas Lectures, George Porter amazed children in the audience by making nylon right there in the lecturessolved theatre. ( 🎥 Royal Institution (now on Bluesky) )
Prof. Carl Sagan369,551 次观看 • 5 个月前
0:52
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Carl Sagan explained in his 1977 Christmas Lectures that Earth's initial hydrogen-rich atmosphere was lost to space because Earth's gravity was too weak to hold onto the light hydrogen atoms, which could easily achieve escape velocity. This allowed the atmosphere to evolve into the second, more stable composition (rich in volcanic gases like CO2, methane, etc.) before oxygen became dominant.
Prof. Carl Sagan200,181 次观看 • 5 个月前
2:04
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