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  2. List of decades, centuries, and millennia - Wikipedia

    en.wikipedia.org/wiki/List_of_decades,_centuries...

    List of decades, centuries, and millennia. The list below includes links to articles with further details for each decade, century, and millennium from 15,000 BC to AD 3000. Century. Decades. 15th millennium BC · 15,000–14,001 BC. 14th millennium BC · 14,000–13,001 BC. 13th millennium BC · 13,000–12,001 BC. 12th millennium BC · 12,000 ...

  3. Unit of time - Wikipedia

    en.wikipedia.org/wiki/Unit_of_time

    10 −9 s: One billionth of a second. Time for molecules to fluoresce. shake: 10 −8 s: 10 nanoseconds, also a casual term for a short period of time. microsecond: 10 −6 s: One millionth of a second. Symbol is μs millisecond: 10 −3 s: One thousandth of a second. Shortest time unit used on stopwatches. jiffy (electronics) ~ 10 −3 s

  4. List of recessions in the United States - Wikipedia

    en.wikipedia.org/wiki/List_of_recessions_in_the...

    10 years 6.3% (June 2003) −0.3% The 1990s were the longest period of economic growth in American history up to that point. The collapse of the speculative dot-com bubble, a fall in business outlays and investments, and the September 11th attacks, [73] brought the decade of growth to an end. Despite these major shocks, the recession was brief ...

  5. Orders of magnitude (time) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(time)

    5.4 × 10 83 Qs (1.7 × 10 106 years): The approximate lifespan of a supermassive black hole with a mass of 20 trillion solar masses [21] 10 10 10 76.66 {\displaystyle 10^{10^{10^{76.66}}}} Qs: The scale of an estimated Poincaré recurrence time for the quantum state of a hypothetical box containing an isolated black hole of stellar mass [ 22 ...

  6. Timelines of world history - Wikipedia

    en.wikipedia.org/wiki/Timelines_of_world_history

    These timelines of world history detail recorded events since the creation of writing roughly 5000 years ago to the present day. For events from c. 3200 BC – c. 500 see: Timeline of ancient history. For events from c. 500 – c. 1499, see: Timeline of post-classical history. For events from c. 1500, see: Timelines of modern history.

  7. Geologic time scale - Wikipedia

    en.wikipedia.org/wiki/Geologic_time_scale

    The geologic time scale, proportionally represented as a log-spiral with some major events in Earth's history. A megaannus (Ma) represents one million (10 6) years. The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses ...

  8. Gregorian calendar - Wikipedia

    en.wikipedia.org/wiki/Gregorian_calendar

    The Gregorian calendar, like the Julian calendar, is a solar calendar with 12 months of 28–31 days each. The year in both calendars consists of 365 days, with a leap day being added to February in the leap years. The months and length of months in the Gregorian calendar are the same as for the Julian calendar.

  9. Human history - Wikipedia

    en.wikipedia.org/wiki/Human_history

    Human history. 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 populated most of the Earth by the end of the Ice Age 12,000 years ago.