Why does datetime.timedelta only have the attributes 'days' and 'seconds'?
MRAB
python at mrabarnett.plus.com
Tue Apr 19 16:06:20 EDT 2022
On 2022-04-19 19:23, Dennis Lee Bieber wrote:
> On Tue, 19 Apr 2022 15:51:09 +0200, "Loris Bennett"
> <loris.bennett at fu-berlin.de> declaimed the following:
>
>>If I am merely trying to represent part a very large number of seconds
>>as a number of years, 365 days per year does not seem that controversial
>
> The Explanatory Supplement to the Astronomical Almanac (table 15.3)
> defines the /day/ as 24hrs->1440mins->86400secs BUT defines the Julian
> /year/ as 365.25 days.
>
So, a /day/ is a solar day, as distinct from a sidereal day.
What's the difference?
Well, a "sidereal day" is how long it takes for the Earth to rotate on
its axis, but as it's also orbiting the Sun in the same direction,
midday won't happen until a little later, hence "solar day".
[snip]
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