Final answer:
The earliest unverified evidence of life exists in the Hadean Eon, estimated to be between 4.1 and 3.8 billion years ago. Solid geological evidence of actual life dates back to the Archaean Eon, around 3.5-3.95 billion years ago.
Step-by-step explanation:
The earliest unverified evidence of life exists in the Hadean Eon, which is estimated to be between 4.1 and 3.8 billion years ago. Solid geological evidence of actual life dates back to the Archaean Eon, around 3.5-3.95 billion years ago. Softer evidence of microbial life, such as graphite and other remains, also exists from this time period.