During the 19th century, the debate regarding Earth's age was renewed, with geologists estimating ages based on denudation rates and sedimentary thicknesses or ocean chemistry, and physicists determining ages for the cooling of the Earth or the Sun using basic thermodynamics or orbital physics. [3]

Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar nebula. [4][5][6] Volcanic outgassing probably created the primordial atmosphere and then the ocean, but the early atmosphere contained almost no oxygen.

2024年5月24日 · Here is a brief look at the four periods of the Geologic Time Scale that track the Earth's history: Precambrian, Paleozoic, Mesozoic, and Cenozoic.

2025年1月17日 · The geologic time scale is the “calendar” for events in Earth history. It subdivides all time into named units of abstract time called—in descending order of duration— eons , eras , periods , epochs , and ages.

Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from the formation of the Sun, which also created the rest of the Solar System. Initially, Earth was molten due to extreme volcanism and …

Earth's history is characterized by four eons; in order from oldest to youngest, these are the Hadeon, Archean, Proterozoic, and Phanerozoic. Collectively, the Hadean, Archean, and Proterozoic are sometimes informally referred to as the "Precambrian."

Era, a very long span of geological time; in formal usage, the second longest portion of geologic time after an eon. Ten eras are recognized by the International Union of Geological Sciences. An era is composed of one or more geological periods.

2024年12月16日 · The geological time scale (GTS) divides and chronicles earth’s evolutionary history into various periods from the beginning to the present based on definite events that marked a major change in earth’s physical, chemical and biological features.