History of Earth - Wikipedia
Photosynthetic organisms appeared between 3.2 and 2.4 billion years ago and began enriching the atmosphere with oxygen. Life remained mostly small and microscopic until about 580 million years ago , when complex multicellular life arose, developed over time, and culminated in the Cambrian Explosion about 538.8 million years ago.
Geologic time | Periods, Time Scale, & Facts | Britannica
2024年11月19日 · Geologic time, the extensive interval of time occupied by the geologic history of Earth. Formal geologic time begins with the Archean Eon (4.0 billion to 2.5 billion years ago) and continues to the present day. Modern geologic time scales also include the Hadean Eon (4.6 billion to 4.0 billion years ago).
Geologic time scale - Wikipedia
The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years). [3] It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or ...
Earth Timeline: From 4.5 Billion Years Ago To Today
Over 4.5 billion years ago, our solar system formed from a giant molecular cloud that collapsed under its own tremendous gravity. The hot stew of hydrogen and helium gave birth to our sun and flung out a wide disc of gas and particles in the surrounding space.
Earth Timeline: A Guide to Earth's Geological History and Events ...
About 1,000,000,000 years ago, Earth had its first signs of life. Single-celled organisms consumed the sun’s energy. As a waste product, these cyanobacteria eventually filled the oceans and atmosphere with oxygen. Next, an oxygenated atmosphere paved the …
Age of Earth - Wikipedia
According to modern biology, the total evolutionary history from the beginning of life to today has taken place since 3.5 to 3.8 billion years ago, the amount of time which passed since the last universal ancestor of all living organisms as shown by geological dating.
Formation of The Earth : Earth's Birth, Timeline and Layering
2024年7月1日 · Core Formation (4.5-4.4 billion years ago): As Earth’s interior continued to heat up due to radioactive decay and residual heat from its formation, heavy metallic elements like iron and nickel sank toward the center. This process led to the formation of Earth’s metallic core, which is divided into an inner solid core and an outer liquid core.
The Most Detailed Earth Timeline: History, Facts & Origin
2024年10月17日 · • 4 Billion Years Ago: Earth's crust solidifies; early atmosphere forms. • 3.8 Billion Years Ago: First signs of life appear. • 2.5 Billion Years Ago: Oxygen begins accumulating in the atmosphere.
Phanerozoic Eon | Paleozoic, Mesozoic & Cenozoic | Britannica
2024年11月25日 · Phanerozoic Eon, the span of geologic time extending about 541 million years from the end of the Proterozoic Eon (which began about 2.5 billion years ago) to the present. The Phanerozoic, the eon of visible life, is divided into three major spans of …
Precambrian Time Information and Prehistoric Facts - National …
Precambrian time covers the vast bulk of the Earth's history, starting with the planet's creation about 4.5 billion years ago and ending with the emergence of complex, multicelled...