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Questions tagged [time]

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7 votes
2 answers

When was the issue of time zones at different longitudes first described?

What are the earliest recorded acknowledgements of the concept that motivates time zones - that the sun and other celestial objects appear in different parts of the sky to people at different ...
Isaac Moses's user avatar
19 votes
3 answers

When and on what basis was it decided that an hour have 60 minutes and a minute have 60 seconds?

There were always some or he other means of measuring(estimating) the time. But I always wonder that when and how the present time system (1 Hr. = 60 Min., 1 Min. = 60 Sec.) evolved ?
Amit Tyagi's user avatar
  • 1,478
19 votes
1 answer

How did Ptolemy know that days were unequal lengths?

Apparently Ptolemy was aware of the fact that the duration of time from noon to noon varied by many seconds throughout the course of a year. In modern times this fluctuation in length of day leads to ...
Jagerber48's user avatar
1 vote
1 answer

When and how was it discovered that the sun was in different positions depending upon longitude?

It seems to me that the ancient Greeks knew that geographic location affected the apparent position of the sun in sky but given the lack of rapid travel or communications or reliable clocks, how was ...
releseabe's user avatar
  • 1,193
10 votes
3 answers

What is the historical basis for the length of a year?

It is currently accepted that a year is equal to the time it takes for the earth to revolve around the sun. However around Roman times, Ptolemy's geocentric model was the widely accepted view of ...
cspirou's user avatar
  • 251