What makes sunrise and sunset times?
Jan. 18th, 2010 04:29 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
conuly
Oh, don't give me "earth's rotation" and "angle of the sun", I know that! But...
Look, I googled to find what time sunset was in NYC, found out that today it's 4:55. Sunrise was at 7:17 Okay, fine.
But in Anchorage it's sunrise at 9:52, but sunset only at 4:27. The sun rises two hours later there, but it only sets about thirty minutes earlier? I'd always assumed it was constant - if it rises an hour later, it sets an hour earlier, that sort of thing. And over in Honalulu the sun rose at 7:12 (barely earlier than here in NYC) but it doesn't set until 6:12. Maybe my problem is in viewing my own city as the default, and if I viewed these times as varying from the equator (or the North Pole) they'd make sense? I understand that summer and winter are more dramatic closer to the poles, and less dramatic close to the equator, but... like I said, I thought you took from both sides of noon more or less evenly wherever you were.
Look, I googled to find what time sunset was in NYC, found out that today it's 4:55. Sunrise was at 7:17 Okay, fine.
But in Anchorage it's sunrise at 9:52, but sunset only at 4:27. The sun rises two hours later there, but it only sets about thirty minutes earlier? I'd always assumed it was constant - if it rises an hour later, it sets an hour earlier, that sort of thing. And over in Honalulu the sun rose at 7:12 (barely earlier than here in NYC) but it doesn't set until 6:12. Maybe my problem is in viewing my own city as the default, and if I viewed these times as varying from the equator (or the North Pole) they'd make sense? I understand that summer and winter are more dramatic closer to the poles, and less dramatic close to the equator, but... like I said, I thought you took from both sides of noon more or less evenly wherever you were.
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Re: What is a day?
Date: 2010-01-20 05:22 pm (UTC)No, the moon is on the order of one light *second* away. 8 minutes is about right for earth–sun.
a calendar and clock systems which we correct for every four years.
The calendar we correct every four years; the clocks we correct irregularly, with leap seconds. (For a while, leap seconds were inserted about every 18 months, but then there was a pretty long "dry spell".)
everyone who replies to your postings is helping to restore a lost piece of literature
Those CAPTCHAs are just shown to anonymous commenters; users with a LiveJournal account aren't shown one. (At least, this is my guess; it could also be that I don't see one because I'm on her friends list, but it seems more likely to turn on CAPTCHAs only for anonymous comments, not for all non-friend comments.)
Re: What is a day?
Date: 2010-01-22 05:20 am (UTC)Re: What is a day?
Date: 2010-01-22 05:47 am (UTC)Re: What is a day?
Date: 2010-01-22 05:51 am (UTC)Re: What is a day?
Date: 2010-01-22 05:51 am (UTC)Re: What is a day?
Date: 2010-01-22 05:54 am (UTC)Re: What is a day?
Date: 2010-01-22 05:58 am (UTC)