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:
“For with this desire of physical beauty mingled itself early the fear of death—the fear of death intensified by the desire of beauty.”
—Walter Pater 1839–1894, British writer, educator. originally published in Macmillan’s Magazine (Aug. 1878)
“We have seen when the earth had to be prepared for the habitation of man, a veil, as it were, of intermediate being was spread between him and its darkness, in which were joined in a subdued measure, the stability and insensibilty of the earth, and the passion and perishing of mankind.”
—John Ruskin (1819–1900)