# Purple Earth hypothesis

> astrobiological hypothesis that life forms of early Earth were retinal-based rather than chlorophyll-based, making Earth appear purple rather than green

**Wikidata**: [Q7261408](https://www.wikidata.org/wiki/Q7261408)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Purple_Earth_hypothesis)  
**Source**: https://4ort.xyz/entity/purple-earth-hypothesis