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Purple Earth Hypothesis: A New Look at Life's Origins

10/16/2025

Summary

Story summary

The Purple Earth Hypothesis suggests Earth billions of years ago may have appeared purple because life used retinal instead of chlorophyll.
Edward Schwieterman and Shiladitya DasSarma, scientists, proposed that early life thrived without plants or oxygen, reflecting red and blue light.
The idea could reshape our view of Earth's past and guide the search for retinal-based life on exoplanets, as described in the International Journal of Astrobiology.

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Story summary

The Purple Earth Hypothesis suggests Earth billions of years ago may have appeared purple because life used retinal instead of chlorophyll.
Edward Schwieterman and Shiladitya DasSarma, scientists, proposed that early life thrived without plants or oxygen, reflecting red and blue light.
The idea could reshape our view of Earth's past and guide the search for retinal-based life on exoplanets, as described in the International Journal of Astrobiology.