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Thu, 12 Apr 2001 15:02:10 -0500 |
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I don't know that anyone else is interested, but Ralph asked:
><< This is the day that you lose or gain depending on whether
> you think that a rotation of the earth is achieved when it
> reaches the same position relative to the sun or to the stars.
> The difference is one day every year.
> Do I make myself clear?
> A sketch would help but I don't have a chalkboard here. >>
>
>If you had the chalkboard, would your sketch explain how, if the time is made
>up in the course of a year, it isn't off by 12 hours in the middle of the
>year, allowing us all to eat lunch in the dark?
>Ralph
Actually, naturally enough, you eat lunch
according to the *solar* day. So it's the *sidereal* day that drifts,
and six months later, a completely different set of stars will rise
after sunset. Every night, a given star rises 4 minutes earlier
than the previous night. Thus we have winter stars and summer stars
and they're not the same. Or, the evening stars of summer
are the same as the morning stars of winter.
If you eat lunch by the stars, and your first lunch is midday,
six months later your lunch will be midnight.
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