Free Republic
Browse · Search
General/Chat
Topics · Post Article

Skip to comments.

The Dog Days and Sothic Cycles of August
universetoday.com ^ | on August 4, 2015 | David Dickinson

Posted on 08/04/2015 12:40:45 PM PDT by BenLurkin

Egyptians livelihood rested on knowing when the annual flooding of the Nile was about to occur. To this end, they relied on the first seasonal spotting of Sirius at dawn. Sirius is the brightest star in the sky, and you can just pick out the flicker of Sirius in early August low to the southeast if you know exactly where to look for it.

Sirius lies at a declination of just under 17 degrees south of the celestial equator. It’s interesting to note that in modern times, the annual flooding of the Nile (prior to the completion of the Aswan Dam in 1970) is commemorated as occurring right around August 15th. Why the discrepancy? Part of it is due to the 26,000 year wobbling of the Earth’s axis known as the Precession of the Equinoxes; also, the Sothic calendar had no intercalculary or embolismic (think leap days) to keep a Sothic year in sync with the sidereal year. The Sothic cycle from one average first sighting of Sirius to another is 365.25 days, and just 9 minutes and 8 seconds short of a sidereal year.

But that does add up over time. German historian Eduard Meyer first described the Sothic Cycle in 1904, and tablets mention its use as a calendar back to 2781 BC. And just over 3 Sothic periods later (note that 1460= 365.25 x 4, which is the number of Julian years equal to 1461 Sothic years, as the two cycles ‘sync up’), and the flooding of the Nile now no longer quite coincides with the first sighting of Sirius.

Such a simultaneous sighting with the sunrise is known in astronomy as a heliacal rising.

(Excerpt) Read more at universetoday.com ...


TOPICS: Astronomy
KEYWORDS: sirius; sothiccycles

1 posted on 08/04/2015 12:40:46 PM PDT by BenLurkin
[ Post Reply | Private Reply | View Replies]

To: BenLurkin
Sirius is the brightest star in the sky

Nuh, uh.


2 posted on 08/04/2015 1:02:01 PM PDT by rjsimmon (The Tree of Liberty Thirsts)
[ Post Reply | Private Reply | To 1 | View Replies]

To: rjsimmon

Well, it’s a good thing that that cactus is holding the sun up, isn’t it ...


3 posted on 08/04/2015 1:02:43 PM PDT by BlueLancer (Once is happenstance. Twice is coincidence. Three times is enemy action.)
[ Post Reply | Private Reply | To 2 | View Replies]

To: BenLurkin

HUGH & SERIES

4 posted on 08/04/2015 1:06:15 PM PDT by JoeProBono (SOME IMAGES MAY BE DISTURBING VIEWER DISCRETION IS ADVISED;-{)
[ Post Reply | Private Reply | To 1 | View Replies]

To: BlueLancer

Somebody’s gotta do it. It ain’t like the sun is hanging there in a void.


5 posted on 08/04/2015 1:54:33 PM PDT by rjsimmon (The Tree of Liberty Thirsts)
[ Post Reply | Private Reply | To 3 | View Replies]

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
General/Chat
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson