Hadean

The Hadean ( ) is the first and oldest of the four geologic eons of Earth's history, starting with the planet's formation about 4.6 Ga (estimated 4567.30 ± 0.16 Ma set by the age of the oldest solid material in the Solar System—protoplanetary disk dust particles—found as chondrules and calcium–aluminium-rich inclusions in some meteorites about 4.567 Ga), and ending 4.031 Ga, the age of the oldest known intact rock formations on Earth as recognized by the International Commission on Stratigraphy. The interplanetary collision that created the Moon occurred early in this eon. The H

hypothesized event, occurring ca. 4.1–3.8 billion years ago, during which a large number of asteroids collided with the Moon, Mercury, Venus, Earth, and Mars

hypotheses for the possible sources of the water on Earth

rock that is among the oldest known crustal fragments on Earth

runaway melting of early earth's interior as a result of potential energy release from sinking iron and nickel melted by heat of radioactive decay

proposed era of the Hadean eon