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The categorisation of the past into discrete, quantified named blocks of time is called periodization. [1] This is a list of such named time periods as defined in various fields of study. These can be divided broadly into prehistorical periods and historical periods (when written records began to be kept).
The idea of using atomic transitions to measure time was first suggested by the British scientist Lord Kelvin in 1879, [204] although it was only in the 1930s with the development of magnetic resonance that there was a practical method for measuring time in this way. [205] A prototype ammonia maser device was built in 1948 at NIST. Although ...
11th century - Large town clocks were used in Europe to display local time, maintained by hand; 1335 - First known mechanical clock, in Milan; 1502 - Peter Henlein builds the first pocketwatch; 1522 - The Portuguese navigator Ferdinand Magellan used 18 hourglasses on each ship during his circumnavigation of the globe. [5]
[40] [41] Ancient history includes the recorded Greek history beginning in about 776 BC (First Olympiad). This coincides roughly with the traditional date of the founding of Rome in 753 BC and the beginning of the history of Rome. [42] [43] 776 BC: First recorded Ancient Olympic Games.
Time is the continuous progression of our changing existence that occurs in an apparently irreversible succession from the past, through the present, and into the future. [1] [2] [3] It is a component quantity of various measurements used to sequence events, to compare the duration of events (or the intervals between them), and to quantify rates of change of quantities in material reality or ...
Timekeeping was important to Vedic rituals, and Jyotisha was the Vedic-era field of tracking and predicting the movements of astronomical bodies in order to keep time, in order to fix the day and time of these rituals, [18] [19] [20] which were developed around the end of 2nd millennium BC as mentioned in "Sathapatha Brahmana".
The first recorded example of a library catalog. [211] 688 BC: Waterproof concrete in use, by the Assyrians. [212] Later, the Romans developed concretes that could *set* underwater, [213] and used concrete extensively for construction from 300 BC to 476 AD. [214] 650 BC: Crossbow in China. [215] 650 BC: Windmills in Persia.
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