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TwitterThe solar time was well defined in the equation of time presented by Ptolemy about two thousands year ago. The equation analyze the earths motion on its axis and around the sun in different period of a year to measure time. The equation was a subject matter of Astronomers until recently.
Ancient people used sundial to measure time until the last centuries invention of mechanical clock take over timekeeping from sundial. Although modern people do not use sundial to keep time but they use to buy or collect sundials as a matter of curiosity and antiquity. They observe the difference between the sundial time and their clock time and the issue of the Ptolemy's`s equation of time came in light again.
The earth is rotating on its own axis and it is spinning around the sun as well. It takes approximately 365 days or a year for the earth to finish it`s full orbit around the sun , and this path is not circular it is elliptical. So, the earth come close to the sun for several months in a year and according to Kepler's law the spinning motion of earth on it`s axis become faster during this time. This phenomenon influence on a major measurement our clocks are based on, that is it counts the day with 24 hours. But, when each spins very fast at that closer time to the sun, it actually spins around its axis less than 24 hours.
That make a lot of difference between time when we measure it upon solar basis and and measure it upon a regular clock basis. Scientists estimated that the difference become 14 minutes in Mid-February and just over 16 minutes in mid November. On the other hand, when earth gets further than the sun , it takes a bit more than 24 hours to finish a spin on axis or meridian. So, the clock gives us a average time all over year which is roughly 24 hours; but it is not totally accurate. But, it works as the minor change does not give any significant effect on our daily life.
Ancient people used sundial to measure time until the last centuries invention of mechanical clock take over timekeeping from sundial. Although modern people do not use sundial to keep time but they use to buy or collect sundials as a matter of curiosity and antiquity. They observe the difference between the sundial time and their clock time and the issue of the Ptolemy's`s equation of time came in light again.
The earth is rotating on its own axis and it is spinning around the sun as well. It takes approximately 365 days or a year for the earth to finish it`s full orbit around the sun , and this path is not circular it is elliptical. So, the earth come close to the sun for several months in a year and according to Kepler's law the spinning motion of earth on it`s axis become faster during this time. This phenomenon influence on a major measurement our clocks are based on, that is it counts the day with 24 hours. But, when each spins very fast at that closer time to the sun, it actually spins around its axis less than 24 hours.
That make a lot of difference between time when we measure it upon solar basis and and measure it upon a regular clock basis. Scientists estimated that the difference become 14 minutes in Mid-February and just over 16 minutes in mid November. On the other hand, when earth gets further than the sun , it takes a bit more than 24 hours to finish a spin on axis or meridian. So, the clock gives us a average time all over year which is roughly 24 hours; but it is not totally accurate. But, it works as the minor change does not give any significant effect on our daily life.
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