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The Lower Paleolithic period lasted over 3 million years, during which there many human-like species evolved including toward the end of this period, Homo sapiens.The original divergence between humans and chimpanzees occurred 13 (), however interbreeding continued until as recently as 4 Ma, with the first species clearly belonging to the human (and not chimpanzee) lineage being ...
Pages in category "20th-century inventions" The following 126 pages are in this category, out of 126 total. This list may not reflect recent changes. A.
The 20th century saw mathematics become a major profession. As in most areas of study, the explosion of knowledge in the scientific age has led to specialization: by the end of the century there were hundreds of specialized areas in mathematics and the Mathematics Subject Classification was dozens of pages long. [72]
The electric flash-lamp is a device that uses an electrical circuit to trigger a fuse to ignite explosive powder such as magnesium, for a brief sudden burst of bright light "flash" from a chemical reaction of flash powder burning. It was principally used for flash photography in the early 20th century, but had other uses as well.
1999 Torino scale The Torino scale, invented by Richard P. Binzel in 1999, is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. It was intended as a tool for astronomers and the public to assess the seriousness of collision predictions, by combining probability statistics and ...
The celebration of the 20th century’s ending expressed the popular opinion that New Year's Eve 1999 and New Year's Day 2000 marked the turn of the millennium, while strictly speaking the 20th century ended on New Year's Eve 2000 and the 21st century began on New Year's Day 2001.
Parclo (partial cloverleaf) interchange – developed by planners at the Ministry of Transportation of Ontario (c. 20th century) Quasiturbine – invented in 1996 [58] Road lines – invented by John D. Millar, an engineer for the Ontario Department of Transport.
Early 19th century: The Irish flute is not an instrument indigenous to Ireland; a key figure in its development was English inventor and flautist Charles Nicholson (1775–1810). 1829: The concertina invented by Charles Wheatstone (1802–1875). [31] Early 20th century: The theatre organ developed by Robert Hope-Jones (1859–1914).