In 1000 BC the summer solstice was on July 2nd [pdf]
1–10 of 14 posts
Re: In 1000 BC the summer solstice was on July 2nd [pdf]
#2what is the significance of this?
Re: In 1000 BC the summer solstice was on July 2nd [pdf]
#31581 AD 10 Mar 18:01 11 Jun 19:34 13 Sep 06:54 11 Dec 20:06 00:02
1582 AD 10 Mar 23:56 12 Jun 01:30 13 Sep 12:39 22 Dec 01:54 00:02
1583 AD 21 Mar 05:51 22 Jun 07:16 23 Sep 18:24 22 Dec 07:42 00:02
Looks the single most dramatic shift happened in these two years. Would someone with astronomical chops care to explain a bit?
Re: In 1000 BC the summer solstice was on July 2nd [pdf]
#41581 AD 10 Mar 18:01 11 Jun 19:34 13 Sep 06:54 11 Dec 20:06 00:02 1582 AD 10 Mar 23:56 12 Jun 01:30 13 Sep 12:39 22 Dec 01:54 00:02 1583 AD 21 Mar 05:51 22 Jun 07:16 23 Sep 18:24 22 Dec 07:42 00:02 Looks the single most dramatic shift happened in these two years. Would someone with astronomical chops care to explain a bit?
http://en.wikipedia.org/wiki/Gregorian_calendar
"Four Catholic countries—Spain,[18] Portugal, the Polish–Lithuanian Commonwealth, and most of Italy—implemented the new calendar on the date specified by the bull, with Julian Thursday, 4 October 1582, being followed by Gregorian Friday, 15 October 1582."
Re: In 1000 BC the summer solstice was on July 2nd [pdf]
#51581 AD 10 Mar 18:01 11 Jun 19:34 13 Sep 06:54 11 Dec 20:06 00:02 1582 AD 10 Mar 23:56 12 Jun 01:30 13 Sep 12:39 22 Dec 01:54 00:02 1583 AD 21 Mar 05:51 22 Jun 07:16 23 Sep 18:24 22 Dec 07:42 00:02 Looks the single most dramatic shift happened in these two years. Would someone with astronomical chops care to explain a bit?
[deleted]
Re: In 1000 BC the summer solstice was on July 2nd [pdf]
#6what is the significance of this?
I think it demonstrates precession, and the difference between the tropical and sidereal years.
Of course, the times were actually calculated from the known rate of precession; we couldn't exactly have said that the summer solstice occurred at 22:00 hours on 2nd July, 1000 BCE. There, you know, wasn't even a July then, given that it was named after a dude who wouldn't be born for another 900 years.
EDIT: As mentioned by other comments, it also captures the shift between the Julian and Gregorian calendars.
Re: In 1000 BC the summer solstice was on July 2nd [pdf]
#71581 AD 10 Mar 18:01 11 Jun 19:34 13 Sep 06:54 11 Dec 20:06 00:02 1582 AD 10 Mar 23:56 12 Jun 01:30 13 Sep 12:39 22 Dec 01:54 00:02 1583 AD 21 Mar 05:51 22 Jun 07:16 23 Sep 18:24 22 Dec 07:42 00:02 Looks the single most dramatic shift happened in these two years. Would someone with astronomical chops care to explain a bit?
http://en.wikipedia.org/wiki/Gregorian_calendar "Four Catholic countries—Spain,[18] Portugal, the Polish–Lithuanian Commonwealth, and most of Italy—implemented the new calendar on the date specified by the bull, with Julian Thursday, 4 October 1582, being followed by Gregorian Friday, 15 October 1582."
[deleted]
Re: In 1000 BC the summer solstice was on July 2nd [pdf]
#8The sun didn't change. The way people date the sun did.
A Julian calendar prior to October 1582 and from there on a Gregorian calendar
Re: In 1000 BC the summer solstice was on July 2nd [pdf]
#9The sun didn't change. The way people date the sun did. A Julian calendar prior to October 1582 and from there on a Gregorian calendar http://en.wikipedia.org/wiki/Gregorian_calendar
And there was no July in 1000 BC as the month is named after some Julius Ceasar who lived quite a bit later. The whole argument is a silly, ahistoric play on calendar definitions.
Re: In 1000 BC the summer solstice was on July 2nd [pdf]
#10This posting made me look back to another posting on HN some time ago about 'Falsehoods Programmers believe about Time'.
My HN search fu is not great, it took me a while to find the posting so I post it here for the convenience of others: https://news.ycombinator.com/item?id=4128208