Early Earth is a term usually defined as Earth's first billion years, or gigayear. On the geologic time scale, this comprises all of the Hadean eon (itself unofficially defined), as well as the Eoarchean and part of the Paleoarchean eras of the Archean eon.
This period of Earth's history, being its earliest, involved the planet's condensation from a solar nebula and accretion from meteorites, as well as the formation of the earliest atmosphere and hydrosphere. It was also defined by the emergence of life and, later, photosynthesis. The earliest supracrustals (such as the Isua greenstone belt) date from the latter half of this period, about 3.8 gya, around the same time as peak late heavy bombardment.
Famous quotes containing the words early and/or earth:
“The girl must early be impressed with the idea that she is to be “a hand, not a mouth”; a worker, and not a drone, in the great hive of human activity. Like the boy, she must be taught to look forward to a life of self-dependence, and early prepare herself for some trade or profession.”
—Elizabeth Cady Stanton (1815–1902)
“Let us say it now: to be blind and to be loved, is indeed, upon this earth where nothing is complete, one of the most strangely exquisite forms of happiness.”
—Victor Hugo (1802–1885)