~1–1.5 billion more years (before severe surface water/oxygen decline)
Sun’s remaining main-sequence life
~5 billion years
Life on Earth — ultra-brief evolution ladder
Prokaryotes (Archaea/Bacteria) dominate early Earth → GOE ~2.4 Ga (oxygen rise).
Eukaryotes emerge ~1.8–2.1 Ga → multicellular eukaryotes diversify Ediacaran (~635–541 Ma) → Cambrian explosion 541 Ma → plants colonise land ~470 Ma → vertebrates on land ~360–300 Ma → non-avian dinosaurs ~230–66 Ma → mammals/radiations 66 Ma–present. (Synthesised from USGS/NASA timelines and standard geologic time scales.)
Sources
NASA, USGS, UN, National Geographic, NOAA, IHO S-23, Peer-reviewed Studies on oxygen decline/runaway greenhouse windows.
