What is the lowest era ever?

The lowest era in geological terms is often considered to be the Hadean Eon, which spans from the formation of the Earth about 4.6 billion years ago to about 4 billion years ago. This period is characterized by extreme heat, volcanic activity, and the formation of the Earth's crust, with no known life existing yet. The name "Hadean" is derived from Hades, reflecting the hellish conditions on the planet during this time.