Why is earth's rotation period < 24hrs

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Homework Help Overview

The discussion revolves around the difference between the Earth's rotational period relative to distant stars and the solar day, specifically why we use a 24-hour clock despite the Earth's rotation period being approximately 23 hours and 56 minutes.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the definitions of timekeeping based on solar versus sidereal days and question the implications of these definitions on our understanding of time.

Discussion Status

Some participants have provided insights into the relationship between Earth's rotation and timekeeping, noting the practical reasons for using the Sun as a reference. There is an ongoing exploration of the differences in time measurement without a clear consensus on all aspects of the topic.

Contextual Notes

The original poster mentions that the question is not for marks but is intended to impress a teacher, indicating a non-graded context for the inquiry. There is also a suggestion to consider the fraction of a day in minutes, which may imply a focus on mathematical reasoning related to the problem.

dowjonez
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Hey anyone who can give me a hand. I've been racking my brain over this question my teacher told me to think about for next class. Its not worth any marks or anything but it might impress him. I would rather ask here then google it. Why do we use a 24hrs on our clocks if the rotational period of the Earth is 23 hrs 56 minutes?
 
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The difference has to do with whether you want to define the rotation of the Earth with respect to the sun, or with respect to the distant stars. Maybe you should find out what one 365th of a day is, in minutes.

Carl
 
its about 3.9xxx minutes thanks carl
 
It's much more convenient for us to use the Sun as a reference for keeping time, since our biological behavior is inextricably linked to it.

On the other hand, we're moving around the Sun about one degree per day, while we practically don't move at all with respect to the very distant stars. This means that every day, the Earth has to turn about one degree further to return to the same position relative to the Sun as it does to return to the same position relative to the distant stars. That extra one degree of rotation takes about four minutes to complete, making the solar day about four minutes longer than the sidereal day.

- Warren
 

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