冥王代

(1)the earliest eon in the history of the Earth from the first accretion of planetary material (around 4,600 million years ago) until the date of the oldest known rocks (about 3,800 million years ago); no evidence of life

(2)惑星物質の添加から（約46億年前）最も古く知られる惑星の岩石（38億年前について）までの最も早い地球歴史の累代

(3)生きている徴候がない