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The Younger Dryas impact hypothesis (YDIH) proposes that the onset of the Younger Dryas (YD) cool period at the end of the Last Glacial Period, around 12,900 years ago was the result of some kind of cosmic event with specific details varying between publications. [1]: Sec 1 The hypothesis is widely rejected by relevant experts.
The Silurian hypothesis is a thought experiment, [1] which assesses modern science's ability to detect evidence of a prior advanced civilization, perhaps several million years ago. The most probable clues for such a civilization could be carbon , radioactive elements or temperature variation.
The Younger Dryas (YD, Greenland Stadial GS-1) [2] was a period in Earth's geologic history that occurred circa 12,900 to 11,700 years Before Present (BP). [3] It is primarily known for the sudden or "abrupt" cooling in the Northern Hemisphere, when the North Atlantic Ocean cooled and annual air temperatures decreased by ~3 °C (5.4 °F) over North America, 2–6 °C (3.6–10.8 °F) in Europe ...
Extinction Date Probable causes [2] Quaternary: Holocene extinction: c. 10,000 BC – Ongoing: Humans [3] Quaternary extinction event: 640,000, 74,000, and 13,000 years ago: Unknown; may include climate changes, massive volcanic eruptions and Humans (largely by human overhunting) [4] [5] [6] Neogene: Pliocene–Pleistocene boundary extinction: 2 Ma
The most recent and best-known, the Cretaceous–Paleogene extinction event, which occurred approximately 66 Ma (million years ago), was a large-scale mass extinction of animal and plant species in a geologically short period of time. [72]
Expansion of early modern humans from Africa. The Upper Paleolithic (or Upper Palaeolithic) is the third and last subdivision of the Paleolithic or Old Stone Age.Very broadly, it dates to between 50,000 and 12,000 years ago (the beginning of the Holocene), according to some theories coinciding with the appearance of behavioral modernity in early modern humans.
Human history is the record of humankind from prehistory to the present. Modern humans evolved in Africa around 300,000 years ago and initially lived as hunter-gatherers.They migrated out of Africa during the Last Ice Age and had spread across Earth's continental land except Antarctica by the end of the Ice Age 12,000 years ago.
The Holocene (/ ˈ h ɒ l. ə s iː n,-oʊ-, ˈ h oʊ. l ə-,-l oʊ-/) [2] [3] is the current geological epoch, beginning approximately 11,700 years ago. [4] It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. [4] The Holocene and the preceding Pleistocene [5] together form the Quaternary period.