1.6-billion-year-old steroid fossils hint at a lost world of microbial life

Wild. I for one would not have guessed that we could detect even moderately complex organic molecules from 1.6 billion years ago.

[Image description: Geochemist Jochen Brocks and colleagues report they discovered the earliest molecular footprints of eukaryotes, dating back 1.6 billion years, in this Barney Creek rock formation in northern Australia.]