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The earliest evidence for life on Earth includes: 3.8 billion-year-old biogenic hematite in a banded iron formation of the Nuvvuagittuq Greenstone Belt in Canada; [30] graphite in 3.7 billion-year-old metasedimentary rocks in western Greenland; [31] and microbial mat fossils in 3.48 billion-year-old sandstone in Western Australia.
According to evidence from radiometric dating and other sources, Earth formed about 4.54 billion years ago. [7] [8] [9] The current dominant theory of planet formation suggests that planets such as Earth form in about 50 to 100 million years but more recently proposed alternative processes and timescales have stimulated ongoing debate in the planetary science community. [10]
This contributed to further cooperation and intellectual development. [195]: 7 Modern humans (Homo sapiens) are believed to have originated around 200,000 years ago or earlier in Africa; the oldest fossils date back to around 160,000 years ago. [196]
Two species are described in the literature: A. ramidus, which lived about 4.4 million years ago [32] during the early Pliocene, and A. kadabba, dated to approximately 5.6 million years ago [33] (late Miocene). A. ramidus had a small brain, measuring between 300 and 350 cm 3.
Prehistory – Period between the appearance of Homo ("humans"; first stone tools c. three million years ago) and the invention of writing systems (for the Ancient Near East: c. five thousand years ago). Paleolithic – the earliest period of the Stone Age Lower Paleolithic – time of archaic human species, predates Homo sapiens
6000 BC: Evidence of habitation at the current site of Aleppo dates to about c. 8,000 years ago, although excavations at Tell Qaramel, 25 kilometres (16 mi) north of the city show the area was inhabited about 13,000 years ago, [124] Carbon-14 dating at Tell Ramad, on the outskirts of Damascus, suggests that the site may have been occupied since ...
While an incorrect model, it was a precursor to the development of Fourier series. 2nd century BC: Hipparchos discovers the apsidal precession of the Moon's orbit. [62] 2nd century BC: Hipparchos discovers Axial precession. 2nd century BC: Hipparchos measures the sizes of and distances to the Moon and Sun. [63] 190 BC: Magic squares appear in ...
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...